home Accounting Steel 20 GOST 1050 88 mechanical properties. Rolled bars, calibrated, with a special surface finish from quality carbon structural steel

Steel 20 GOST 1050 88 mechanical properties. Rolled bars, calibrated, with a special surface finish from quality carbon structural steel

Steel 20. Application in production.

The use of steel 20 in general engineering is ubiquitous. From this material, load-gripping parts of cranes, various fingers, pipes, replaceable elements of plain bearings are made. Pipe fittings made of steel 20 are characterized by resistance to high working pressure in the pipelines.

We are interested in the “profile” use of steel 20. Some sources indicate that it is acceptable to manufacture worm gear elements from St 20, namely a worm. This is not a completely correct statement. In its "pure" form, this steel is not used in gearboxes. The manufacture of worms and gears for newly produced drive mechanisms from low-carbon steels, to which Steel 20 belongs, is allowed only if alloying elements are present in it. The composition in larger proportions should contain chromium, manganese and molybdenum. If the part is produced for repair purposes, then it must go through a carburizing process, because steel 20, due to its initial carbon content, does not hold hardened. But grouting requires expensive chemical-thermal equipment, which can only be afforded by specialized narrowly specialized enterprises.

AT mass production parts of drive mechanisms, a strip of Steel 20 is used. Assembly units drive roller chains, connecting and transitional links. This product is small in size and does not require a large carburizing furnace chamber.

Chemical composition of Steel 20.

For all carbon steels, the most significant is the percentage of carbon in the total composition. This indicator is indicated in the brand in hundredths of a percent. The complete chemical composition of Steel 20 will be as follows:

Steel 20 GOST.

The production of all the most significant products from Steel 20 is regulated by the following standards (GOST):

long products, including shaped steel - GOST 1050-88, GOST 2590-2006, GOST 2591-2006, GOST 2879-2006, GOST 8509-93, GOST 8510-86, GOST 8240-97, GOST 8239-89;
calibrated bar - GOST 7417-75, GOST 8559-75, GOST 8560-78, GOST 10702-78;
ground rod and silver - GOST 14955-77;
thick sheet - GOST 1577-93, GOST 19903-74;
thin sheet - GOST 16523-97;
tape - GOST 6009-74, GOST 10234-77, GOST 103-2006, GOST 82-70;
wire - GOST 5663-79, GOST 17305-91;
forgings and forged blanks - GOST 8479-70;
pipes - GOST 10704-91, GOST 10705-80, GOST 8731-74, GOST 8732-78, GOST 8733-74, GOST 5654-76, GOST 550-75.

Steel 20. Mechanical properties.

Mechanical characteristics at elevated temperatures

Test temperature, °C	σ0.2, MPa	σВ, MPa	δ5, %	ψ, %	KCU, J/cm2
20	280	430	34	67	218
200	230	405	28	67	186
300	170	415	29	64	188
400	150	340	39	81	100
500	140	245	40	86	88
700		130	39	94
800		89	51	96
900		75	55	100
1000		47	63	100
1100		30	59	100
1200		20	64	100

Mechanical properties of Steel 20 at a temperature of +20C.

Regulatory document	Delivery status	σB (MPa)	δ 5 (%)	ψ (%)	HB (no more)
GOST 1050-74	Steel calibrated:
	hot-rolled, forged and silver plate of the 2nd category after normalization	410	25	55
	5th category after work hardening	490	7	40
	Grade 5 after annealing or high tempering	390	21	50
GOST 10702-78	Steel calibrated and calibrated with special finishes:
	after tempering or annealing	390-490		50	163
	after spheroidizing annealing	340-440		50	163
	cold-worked without heat treatment	490	7	40	207
GOST 1577-81	Strips normalized or hot rolled	410	25	55
GOST 4041-71	Heat-treated sheet 1-2 category	340-490	28		127

Mechanical properties of forgings

heat treatment	KP	Section, mm	σ0.2, MPa	σВ, MPa	δ5, %	ψ, %	KCU, J/m2	HB, no more
Normalization	175	less than 100	175	350	28	55	64	101-143
	175	100-300	175	350	24	50	59	101-143
	175	300-500	175	350	22	45	54	101-143
	175	500-800	175	350	20	40	49	101-143
	195	less than 100	195	390	26	55	59	111-156
	195	100-300	195	390	23	50	54	111-156
	215	less than 100	215	430	24	53	54	123-167
	215	100-300	215	430	20	48	49	123-167
hardening. Vacation	245	100-300	245	470	19	42	39	143-179

Mechanical properties of steel after chemical-thermal treatment.

Technological properties of Steel 20

Specific gravity		7.85 g/cm3
Material hardness	Steel 20 after annealing, GOST 1050-88	HB 10 -1 = 163 MPa
	Bar calibrated hard-worked, GOST 1050-88	HB 10 -1 = 207 MPa
	Heat-treated sheet. GOST 4041-71	HB 10 -1 = 127 MPa
	Hot-formed pipes, GOST 550-75	HB 10 -1 = 156 MPa
	Pipes, GOST 8731-87	HB 10 -1 = 156 MPa
	Thick annealed sheet, GOST 1577-93	HB 10 -1 = 156 MPa
Temperature of critical points	Ac 1	735
	Ac 3 (Ac m)	850
	Ar 3 (Arc m)	835
	Ar 1	680
Forging temperature	start	1280
	end	750
	cooling	on air
Machinability: hot-rolled at HB 126-131 and δ B =450-490 MPa		To υ tv. cpl \u003d 1.7 and K υ b.st \u003d 1.6
Material weldability		no restrictions, except for parts after chemical heat treatment
Welding methods		RDS, ADS submerged and gas shielded, KTS
Floken sensitivity		not sensitive
Tendency to temper brittleness		not inclined

impact strength.

Impact strength KCU (J/cm3) at low temperatures °С

GOST	Delivery status	Section, mm	KCU at +20	KCU at -40	KCU at -60
19281-73	Sections and shapes	5 to 10	64	39	34
		from 10 to 20 incl.	59	34	29
		from 20 to 100 incl.	59	34	-
19282-73	Sheets and stripes	5 to 10	64	39	34
	Sheets and stripes	from 10 to 60 incl.	59	34	29
	Sheets after hardening, tempering (Samples transverse)	from 10 to 60 incl.	-	49	29

endurance limit

σ -1 , MPa	J -1 , MPa	δ 5 , MPa	σ 0.2, MPa	Heat treatment, steel condition
206		500	320
245		520	310
225		490	280
205	127			Normalization 910 C, vacation 620 C.
193		420	280
255	451			Carburizing 930 C, hardening 810 C, tempering 190 C.

Physical properties of steel 20

Test temperature, °С	20	100	200	300	400	500	600	700	800	900
Modulus of normal elasticity, E, GPa	212	208	203	197	189	177	163	140
Modulus of elasticity in torsion shear G, GPa	78	77	76	73	69	66	59
Density, pn, kg/cm3	7859	7834	7803	7770	7736	7699	7659	7917	7624	7600
Thermal conductivity coefficient λ, W/(m °С)		51	49	44	43	39	36	32	26	26
Oud. electrical resistance, R, (p, NΩ m)		219	292	381	487	601	758	925	1094	1135
Linear expansion coefficient, a, (10-6 1/°С)	12,3	13,1	13,8	14,3	14,8	15,1	15,2
Specific heat, C, J/(kg °C)	486	498	514	533	555	584	636	703	703	695

Also in our catalog are descriptions and characteristics of other steel grades used in the production of drive chains and gearboxes.

STATE STANDARDS

STEEL QUALITY
AND HIGH QUALITY

SOLID AND SHAPED RENTAL,
CALIBRATED STEEL

Part 1

GOST 1050-88

Moscow

IPK STANDARDS PUBLISHING HOUSE

STATE STANDARD OF THE UNION OF THE SSR

Date of introduction 01.01.91

This International Standard specifies general specifications for hot-rolled and forged long products from quality carbon structural steel grades 08, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 58 (55pp) and 60 with a diameter or thickness up to 250 mm, as well as rolled products calibrated and with special surface finishes of all grades.

In terms of chemical composition, the standard applies to other types of rolled products, ingots, forgings, stampings from steel of the grades listed above, as well as from steel grades 05kp, 08kp, 08ps, 10kp, 10ps, 11kp, 15kp, 15ps, 18kp, 20kp and 20ps .

1. MAIN PARAMETERS AND DIMENSIONS

1.1. Grades and chemical composition of steel according to the ladle test must correspond to those given in table. one.

Table 1

steel grade	Mass fraction of elements, %
steel grade	carbon		manganese	chrome, no more
	Not more than 0.06	Not more than 0.03	Not more than 0.40
		Not more than 0.03


		Not more than 0.07


		Not more than 0.06
		Not more than 0.07


		Not more than 0.06
		Not more than 0.07









			Not more than 0.20

Notes:

1. According to the degree of deoxidation, steel is designated: boiling - kp, semi-calm - ps, calm - without an index.

2. Steel grade 05kp is not allowed for use in newly created and modernized equipment.

3. The profile for oblique washers according to GOST 5157 is made of steel grades 20 and 35.

1.1.1. The mass fraction of sulfur in steel should be no more than 0.040%, phosphorus - no more than 0.035%.

For steel grades 11kp and 18kp used for cladding, the mass fraction of sulfur should be no more than 0.035%, phosphorus - no more than 0.030%.

1.1.2. The residual mass fraction of nickel in steel of all grades should not exceed 0.30%, copper in steel grades 11kp and 18kp - 0.20%, in steel of other grades - 0.30%.

1.1.3. In steel grades 35, 40, 45, 50, 55 and 60, intended for the manufacture of patented wire, the mass fraction of manganese should be 0.30–0.60%, nickel - no more than 0.15%, chromium - no more than 0, 15%, copper - no more than 0.20%. The mass fraction of sulfur and phosphorus - in accordance with the requirements of the wire standards, but does not exceed the standards given in paragraph 1.1.1.

1.1.4. In steel grades 08ps, 10ps, 15ps and 20ps, intended for the manufacture of sheet metal for cold stamping, the mass fraction of manganese is allowed up to 0.25% at the lower limit.

1.1.5. In steel grades 08ps, 10ps, 15ps and 20ps, a silicon mass fraction of less than 0.05% is allowed, provided that other (except silicon) deoxidizers are used in the required quantities.

1.1.6. In steel, the mass fraction of arsenic is not more than 0.08%.

1.1.7. The mass fraction of nitrogen in oxygen-converter steel should not exceed 0.006% for rolled sheets and strips and 0.008% for other types of rolled products.

1.1.8. In accordance with the order in the quiet steel, made by the scrap-process and the scrap-ore process, the residual mass fraction of nickel and chromium is allowed not more than 0.40% each.

1.2. In rolled products, blanks, forgings and products of further processing, deviations in chemical composition from the norms given in Table 1 are allowed. 1, in accordance with the table. 2.

table 2

1.3. The range of rolled products must meet the requirements:

GOST 2590 - for hot-rolled round;

GOST 2591 or other normative and technical documentation - for hot-rolled square;

GOST 1133 - for forged round and square;

GOST 2879 - for hot-rolled hexagonal;

GOST 103 - for hot-rolled strip;

GOST 4405 - for forged strip;

GOST 5157 - for a profile for oblique washers;

GOST 7417 - for calibrated round;

GOST 8559 - for calibrated square;

GOST 8560 - for calibrated hexagon;

regulatory and technical documentation - for calibrated strip;

GOST 14955 - with special surface finish.

Examples of symbols are given in Appendix 1.

2. TECHNICAL REQUIREMENTS

2.1. Characteristics of the basic version

2.1.1. Rolled sectioned random (ND) length with maximum deviations for normal dimensional accuracy, curvature, ovality and other requirements for shape, crescent and deviation from flatness class 2 according to GOST 103 (for strip).

2.1.2. Rolled calibrated random (ND) length with maximum deviations for the tolerance field - h11, ovality - no more than the maximum deviations in diameter.

2.1.3. Rolled products with a special surface finish of random (ND) length with maximum deviations for the tolerance field - h11, ovality - no more than half of the maximum deviations in diameter.

2.1.4. Rolled bars without heat treatment, calibrated and with a special surface finish cold-worked - NG or heat-treated (annealed, high-tempered, normalized, normalized with tempering, hardened with tempering) - TO.

2.1.5 Rolled long products of two groups of surface quality: 2GP and 3GP. Rolled products of surface quality group 2GP are intended mainly for hot forming, group 3GP mainly for cold machining.

2.1.6. On the surface of the rolled product of the surface quality group 2ГП there should be no rolled bubbles, rolling films, sunsets, cracks, pollution, stress cracks.

2.1.1–2.1.6. (Revised edition, Rev. No. 1).

2.1.6.1. Defects on the surface must be removed by a shallow cut or by grinding, the width of which must be at least five times the depth.

The depth of cleaning of defects, counting from the actual size, should not exceed:

half of the size tolerance - for rolled products less than 80 mm in size;

size tolerance - for rolled products with sizes from 80 to 140 mm;

5% of diameter or thickness - for rolled products from 140 to 200 mm in size;

6% - diameter or thickness - for rolled products larger than 200 mm.

In one section of rolled products with a size (diameter or thickness) of more than 140 mm, no more than two strippings of maximum depth are allowed.

2.1.6.2. On the surface of the rolled products, individual risks, dents and ripples with a depth of within half the tolerance for size, as well as rolled bubbles and impurities (hairs) with a depth not exceeding 1/4 are allowed without stripping. size tolerance, but not more than 0.20 mm, counting from the actual size.

2.1.7. On the surface of rolled products with a surface quality of group 3ГП, local defects are allowed with a depth not exceeding the minus limit deviation for a size for rolled products with a size of less than 100 mm; size tolerance - for rolled products with a size of 100 mm or more.

Depth of defects is considered from the nominal size.

2.1.8. Rolled products must be cut off.

Wrinkled ends and burrs are allowed.

The oblique cut of long products up to 30 mm in size is not regulated, over 30 mm - should not exceed 0.1 of the diameter or thickness. Bars up to 40 mm in size of random length are allowed to be produced with unedged ends.

2.1.9. Surface quality and requirements for trimming the ends of calibrated rolled products must comply with - GOST 1051 groups B and C, with a special surface finish - GOST 14955 groups C, D and D.

In rolled products with a special surface finish, decarburization is not allowed.

2.1.10. Hardness (ТВ1) of long products without heat treatment should not exceed 255 HB, calibrated and with a special surface finish of hard-worked - 269 HB.

2.1.11. The mechanical properties of rolled products in the normalized state (Ml) must comply with the standards given in Table. 3.

Table 3

steel grade	Mechanical properties, not less than
	Yield strength σ t N/mm 2	Elongation δ	Relative contraction ψ
	Yield strength σ t N/mm 2

Notes:

1. Norms of mechanical properties given in table. 3 apply to rolled products with a diameter or thickness up to 80 mm. For rolled products with a diameter or thickness over 80 mm, a reduction in relative elongation by 2% (abs.) and a relative narrowing by 5% (abs.) is allowed.

The norms of mechanical properties for blanks reforged from bars with a diameter or thickness over 120 to 250 mm for rolled products with a diameter or thickness from 90 to 100 mm must correspond to those given in Table. 3.

2. By agreement between the manufacturer and the consumer for steel grades 25–60, a reduction in tensile strength by 20 N / mm 2 (2 kgf / mm 2) is allowed compared to the standards indicated in table. 3, while increasing the rate of relative elongation by 2% (abs.).

2.1.10; 2.1.11.(Revised edition, Rev. No. 1).

2.1.12. The macrostructure of rolled products should not have a shrinkage cavity, friability, bubbles, delaminations, internal cracks, slag inclusions and flakes.

2.2. User Defined Characteristics

2.2.1. Rolled steel grades 20, 25, 30, 35, 40, 45, 50 mass fraction and boron 0.002–0.006%.

In this case, the letter R is placed at the end of the brand designation.

2.2.2. Rolled steel from calm steel with a mass fraction of silicon 0.17-0.27%.

2.2.3. Rental of measured (MD) lengths.

2.2.4. Rolled length, multiple dimensional (KD).

2.2.5. Rolled products calibrated and with a special surface finish with tolerance h12.

2.2.6. Long products in a heat-treated state (annealed, high-tempered, normalized, normalized with tempering) - TO.

2.2.7. Rolled products with a surface quality of group 1ГП - for rolled bubbles and impurities (hairs) and a hot upset test (65).

Rolled products are mainly intended for hot upsetting, upsetting and stamping.

2.2.8. Rolled steel grades 25, 30, 35, 40, 45, 50 with control of impact strength (IUV) on heat-treated (quenching + tempering) samples.

The norms of impact strength (U B) must correspond to those indicated in Table. 4.

Table 4

steel grade	Impact strength J / cm 2 (kgf. m / cm 2),

2.2.9. Rolled products calibrated in cold-worked or heat-treated state with normalized mechanical properties (M2) in accordance with the requirements specified in Table. 5.

2.2.10. Rolled products with a macrostructure normalized in points (KMS) in accordance with the requirements specified in Table. 6.

2.2.11. Rolled products with normalized hardness (TV2) in accordance with the requirements given in Table. 7.

Table 5

steel grade	Mechanical properties of rolled products, not less than
	cold-worked
		Relative elongation δ,%	Relative contraction ψ,%	Tensile strength σ t, N / mm 2 (kgf / mm 2)	Relative elongation δ,%	Relative contraction ψ,%

Table 6

Macrostructure of steel in points, no more
Central porosity	Point inhomogeneity	Liquation square	General spotted liquation	Marginal spotted liquation	Shrink segregation for rolled products size	Subcortical blisters	Intergranular cracks

						Not allowed

Note. For rolled products with a size of 70 mm or more with a surface quality of group b, subcortical bubbles of grade 2 are allowed to a depth of not more than 1/2, tolerance for diameter or thickness.

Table 7

steel grade	Hardness number HB, no more
	for hot-rolled and forged steel		for calibrated steel and with special surface finish
	without heat treatment	after annealing or high tempering	cold-worked	annealed or highly tempered

2.2.12. Rolled products with ultrasonic testing (UT) of internal defects according to GOST 21120.

2.2.13. Rolled products with weldability (HS).

2.2.14. Rolled steel grades 35, 40, 45, 50, 55, 58 (55pp), 60, intended for surface hardening by high-frequency currents, with decarburization (ferrite + transition zone) no more than 1.5% of the diameter or thickness per side (1C ).

2.2.4–2.2.14 (Revised edition, Rev. No. 1).

2.2.15. (Deleted, Rev. No. 1).

2.3. Characteristics established by agreement between the consumer and the manufacturer

2.3.1. Rental with reduced compared to those given in table. 1 limits by mass fraction of carbon, but not less than 0.05%.

2.3.2. Rental with reduced compared to those given in table. 1 limits on the mass fraction of carbon, but not less than 0.05%, without taking into account the permissible deviations in the finished rolled products indicated in table. 2.

2.3.3. Rolled products with mass fraction of sulfur 0.020–0.040%.

2.3.4. Rolled products with mass fraction of sulfur not more than 0.025%.

2.3.5. Rolled products with a mass fraction of phosphorus not more than 0.030%.

2.3.6. Rolled products with a mass fraction of copper not more than 0.25%.

2.3.7. Long products with a diameter or thickness over 30 to 140 mm with the removal of burrs (US) and crumpled ends.

2.3.8. Hard-worked steel with an increase of 15 HB compared to that shown in table. 7 hardness (TVZ).

2.3.9. Rolled products with normalized mechanical properties (MS) determined on samples cut from heat-treated blanks (quenching + tempering) of the size specified in the order, in accordance with the requirements of Table. eight.

2.3.10. Rolled products with normalized hardenability (PR) in accordance with Annexes 3 and 4.

2.3.11. Rolled steel grades 35, 40, 45, 50, 55, 58 (55pp), 60, intended for surface hardening by high-frequency currents, with decarburization (ferrite + transition zone) not more than 0.5% of the diameter or thickness per side (2С ).

2.3.12. Rental in pickled (T) condition.

2.3.7–2.3.11. (Revised edition, Rev. No. 1).

2.3.13. Rolled products calibrated with tolerance field h10.

2.3.14. High-quality hot-rolled steel of increased (B) and high (A) dimensional accuracy.

Table 8a

Table 8

steel grade

Mechanical properties of rolled products

from 16 to 40 mm

from 40 to 100 mm

Tensile strength σ in N / mm 2 (kgf / mm 2)

Impact work KU, J (kgf. m)

Yield strength σ t N / mm 2 (kgf / mm 2) not less than

Tensile strength σ in N / mm 2 (kgf / mm 2)

Relative elongation δ 5 %

Impact work KU, J (kgf. m)

Yield strength σ t N / mm 2 (kgf / mm 2) not less than

Tensile strength σ in N / mm 2 (kgf / mm 2)

Relative elongation δ 5 %

Impact work KU, J (kgf. m)

Notes:

1. The norms of mechanical properties until 01.01.92 are not rejection, the definition is mandatory.

2. The mechanical properties of steel 30 apply to rolled products up to 63 mm in size.

3. The values of mechanical properties are given for rolled products of round section. For rectangular sections, the ranges of equivalent diameters are given in Appendix 2.

2.3.15. Rolled products with a surface quality of group 2ГП with a hot upset test (65).

Testing of rolled products with the size of St. 80 mm may be omitted by the manufacturer.

2.3.16. Rolled steel grades 45, 50, 50A with hardness control (TV4) on hardened samples in accordance with the requirements specified in table. 8a.

2.3.17. The mass fraction of nitrogen is not more than 0.008% in oxygen-converter steel for thin-sheet rolling.

2.3.13–2.3.17. (Introduced additionally, Amendment No. 1).

2.4. Allowed in the technical conditions for specific products provide for additional or enhanced characteristics not covered by this standard.

The list of additional characteristics is given in Appendix 5.

2.5. Marking and packaging of rolled products - according to .

2.5.1. Packaging of calibrated rolled products - according to, with a special surface finish - according to GOST 14955.

2.5.2. The marking is applied directly to the product if the product is not subject to packaging, and on the label if the product is packed in bundles, coils and coils.

3. ACCEPTANCE RULES

3.1. Rolled products are accepted in batches consisting of steel of the same heat, one size and one heat treatment mode (when manufactured in a heat-treated state).

By agreement between the manufacturer and the consumer, the parties are formed from steel of the same brand of several heats of the same size.

Each batch is accompanied by a quality document according to.

When using deoxidizers other than silicon for semi-quiet steel, a corresponding indication is made in the quality document.

For rental, accepted with the characteristics set by the consumer in accordance with paragraphs. 2.2 and 2.3, the quality document indicates the test results for ordered indicators.

3.2. Rolled products are subjected to acceptance tests.

3.3. To check the quality of the batch of rolled products are selected:

1) for chemical analysis - samples according to GOST 7565. The manufacturer conducts control of residual copper, nickel, chromium, arsenic and nitrogen periodically at least once a quarter. In the manufacture of steel, taking into account the manganese equivalent, the control of residual copper, nickel and chromium is carried out on each heat;

2) to control the quality of the surface and dimensions - all bars, strips and coils;

3) to control the macrostructure by fracture or etching, to test for impact bending, to determine the depth of the decarburized layer - two rods, strips or coils;

4) to test the hardness - 2% bars, strips or coils, but not less than 3 pieces;

5) for tensile testing - one rod, strip or coil for testing in the normalized state, two rods, two strips or two coils for testing in cold-worked, annealed, high-tempered or hardened with tempering condition;

6) to determine the hardenability - one bar, strip or coil from a melting ladle of steel of all grades that do not contain boron, and two bars, two strips or two coils from a melting ladle of steel grades containing boron;

7) to determine the size of the grain - one rod, strip or coil from the melting ladle;

8) for the draft test - three bars, strips or coils;

9) to determine the hardness after hardening - two longitudinal samples from the melt.

(Revised edition, Rev. No. 1).

3.4. Upon receipt of unsatisfactory test results for at least one of the indicators, repeated tests are carried out on it.

The results of repeated tests are extended to the entire batch.

4. TEST METHODS

4.1. Chemical analysis of steel is carried out according to GOST 22536.0 -, GOST 27809, GOST 12359 or other methods in terms of accuracy that are not inferior to standard ones. In case of disagreement chemical analysis carried out according to -, GOST 27809, GOST 12359.

4.2. The surface quality is checked by inspection of rolled products without the use of magnifying devices. If necessary, the surface is brightened or etched, and for rolled products with a special surface finish with a diameter of up to 3 mm inclusive, the inspection is carried out at a magnification of up to 10 x. The depth of occurrence of defects on the surface of the rolled products is determined by control cleaning or filing with a file.

4.3. The geometric dimensions and shape are determined using measuring instruments according to GOST 162, GOST 166, GOST 427, GOST 3749, GOST 5378, GOST 6507, GOST 7502, or tools certified according to GOST 8.001 or GOST 8.326.

4.4. Sampling from coils for all types of tests is carried out at a distance of at least 1.5 turns from the end of the roll.

4.5. From each rod, strip or coil selected for control, the following are taken: for tensile and upset tests, to determine the grain size, hardenability and depth of the decarburized layer - one sample each;

for impact bending testing - one sample of each type;

to control the macrostructure - one template.

4.6. Sampling for slump tests - according to .

4.7. Sampling for testing mechanical properties according to table. 3 and 5 are carried out according to GOST 7564 (option 1), according to the table. 4 and 8 - according to GOST 7564 (option 2).

(Revised edition, Rev. No. 1).

4.7a. Sampling for determination of hardness after hardening is carried out according to the scheme given in Appendix 8.

Samples for control can be cut out from finished rolled products or pig billets (in melting control).

(Introduced additionally, Rev. No. 1).

The samples are heated to a forging temperature of 850-1000°C and upset by 65% relative to the original height. On upset samples there should be no cracks and sunsets.

4.9. Brinell hardness is determined according to GOST 9012. The hardness of rolled products with a diameter or thickness of less than 5 mm is not determined.

4.9a. Rockwell hardness after hardening is determined according to GOST 9013 on a site located in the middle of the sample length. The surface of the platform for measuring hardness is cleaned; in this case, the surface roughness Ra should be no more than 1.25 µm in .

(Introduced additionally, Rev. No. 1).

4.10. The tensile test is carried out according to GOST 1497 on samples of five times the length with a diameter of 5 or 10 mm.

For rolled products with a diameter or thickness up to 25 mm inclusive, the test may be carried out on samples without machining.

The impact strength test is carried out according to GOST 9454 on type 1 samples.

The sample axis direction is along the rolling direction.

4.11. Samples for tensile testing of rolled products in accordance with the requirements of Table. 3 are cut from normalized blanks with a diameter or side of a square of 25 mm.

For bars with a diameter of less than 25 mm, normalization is carried out in the finished section of the bar (without cutting the workpiece).

Note. From bars larger than 120 mm, sampling for mechanical testing can be carried out from reforged or rolled billets with a cross section of 90–100 mm.

4.12. Samples for tensile testing of rolled products in accordance with the requirements of Table. 8 are cut from heat-treated blanks in the size specified by the consumer.

4.13. The modes of heat treatment of blanks (samples) for testing mechanical properties are given in Appendices 6 and 7, for hardness control after hardening - in Appendix 9.

(Revised edition, Rev. No. 1).

4.14. The control of the macrostructure for fracture or etched templates is carried out without the use of magnifying devices according to GOST 10243.

It is allowed to use ultrasonic testing methods (UT) and other non-destructive testing methods agreed in in due course.

4.15. The depth of the decarburized layer is determined according to GOST 1763.

4.16. Hardenability is determined by the method of end hardening according to GOST 5657.

4.17. The grain size is determined according to GOST 5639.

4.18. On steel of one melt, which has passed tests for macrostructure, hardenability and mechanical properties on large rolled profiles, in the manufacture of smaller rolled profiles, the listed tests at the manufacturer may not be carried out.

4.19. It is allowed for the manufacturer to use statistical and non-destructive control methods according to the methodology agreed in the prescribed manner. In case of disagreement and during periodic product quality checks, the control methods provided for in this standard are applied.

5. TRANSPORT AND STORAGE

5.1. Transportation and storage - according to GOST 7566 with the following addition.

5.1.1. Transportation of products is carried out by transport of all types in accordance with the rules for the carriage of goods in force for this type of transport. By railways transportation is carried out depending on the weight and overall dimensions in covered or open wagons. The weight of the package must not exceed during mechanized loading into open vehicles 10000 kg, indoor - 1250 kg. Packaging, means and methods for forming packages - according to .

When sending two or more packages, the dimensions of which allow you to issue a transport package with overall dimensions in accordance with GOST 24597, the packages must be formed into overpacks. Fastening means - according to GOST 21650.

APPENDIX 1
Mandatory

EXAMPLES OF RENTAL SYMBOLS

Scheme 1 symbol rolled

In the design documentation, it is allowed to give examples of symbols in accordance with scheme 2.

Legend Examples

Rolled bars, round, of ordinary rolling accuracy (B), class II in terms of curvature, random length (ND), 100 mm in diameter according to GOST 2590–88, made of grade 30 steel, with a surface quality of group 2GP, with mechanical properties according to Table. 3 (M1), with hardness according to clause 2.1.10 (TB1), with impact strength control according to table. 4 (EFS), with deburring (US), with hot upset test (65), without heat treatment:

Circle B-II-ND-100 GOST 2590-88/30-2GP-M1-TV1-KUV-UZ-66 GOST 1050-88

Rolled bars, square, increased rolling accuracy (B), class I in terms of curvature, measured length (MD), with a square side of 25 mm in accordance with GOST 2591–88, from steel grade 35, with a surface quality of group 1GP, with mechanical properties according to table . 8 (MZ), with hardness according to table. 7 (TV2), with a macrostructure normalized in points (MCS) according to Table. 6, with decarburization according to paragraph 2.2.14 (1C), heat treated (HT):

Square B-I-MD-25 GOST 2591-88/35-1GP-MZ-TV2-KMS-1S-TO GOST 1050-88

Rolled strip, normal rolling accuracy (B), crescent class 2, deviation from flatness class 2, multiple measured length (KD), thickness 36 mm, width 90 mm according to GOST 103–76, from steel grade 45, with a surface quality of group 3GP , with mechanical properties according to Table. 3 (Ml), with hardness according to clause 2.1.10 (TV1), with normalized hardenability (PR), without heat treatment:

Strip V-2-2-KD-36×90 GOST 103-76/45-3GP-M1-TV1-PR GOST 1050-88

Hot-rolled profile for oblique washers, measured length (MD), with dimensions 2BxHxh = 32 × 5.8 × 4 mm according to GOST 5157–83, from steel grade 35, with a surface quality of group 3GP, with mechanical properties according to Table. 3 (Ml), with hardness according to clause 2.1.10 (TB1), without heat treatment:

Profile for oblique washers MD-32×5.8×4 GOST 5157-83/35-3GP-M1-TB1 GOST 1050-88

Rolled calibrated, round, with a tolerance field according to h11, measured length (MD), with a diameter of 10 mm according to GOST 7417–75, from steel grade 45, with a surface quality of group B according to GOST 1051–73, with mechanical properties according to Table. 5 (M2), with hardness according to paragraph 2.3.8 (TVZ), with decarburization according to paragraph 2.3.11 (2C), hard-worked (NG):

Circle h11-MD-10 GOST 7417-75/45-V-M2-TVZ-2S-NG GOST 1050-88

Rolled calibrated, square, with a tolerance field h11, a multiple of the measured length (KD), with a square side of 15 mm according to GOST 8559–75, from steel grade 20, with a group B surface quality according to GOST 1051–73, with mechanical properties according to Table. 8 (MZ), with hardness according to table. 7 (TV2), with ensuring weldability (HS), hard-worked (NG):

Squareh11-KD-15 GOST 8559-75/20-B-MZ-TV2-GS-NG GOST 1050-88

Rolled calibrated, hexagonal, with tolerance field h12, random length (ND), inscribed circle diameter 8 mm according to GOST 8560–78, steel grade 45, surface quality group B according to GOST 1051–73, with mechanical properties according to Table. 3 (Ml), with hardness according to table. 8a (TB4), heat treated (TO):

hexagonh12-ND-8 GOST 8560-78/45-V-M1-TV4-TO GOST 1050–88

Rolled products with a special surface finish, round, with a tolerance field h11, random length (ND), diameter 8 mm, surface quality group B according to GOST 14955–77 from steel grade 20, with mechanical properties according to Table. 5 (M2), with hardness according to table. 7 (TVZ) hard-worked (NG):

A circleh11-ND-8 GOST 14955-77/20-V-M2-TVZ-NG GOST 1050-88

Examples of symbols that are allowed to be given in the design documentation:

Rolled products with a special surface finish, round, with a tolerance field h11, random length (ND), diameter 8 mm, surface quality group B according to GOST 14955–77, made of steel grade 20, with mechanical properties according to table. 5 (M2), with hardness according to table. 7 (TVZ), hard-worked (NG):

A circle .

(Revised edition, Rev. No. 1).

APPENDIX 2
Mandatory

CONVERSION OF RECTANGULAR SECTIONS TO ROUND SECTIONS WITH THE SAME MECHANICAL PROPERTIES

APPENDIX 3
Mandatory

BANDS OF HARDENABILITY
STRUCTURAL CARBON STEEL

Steel grade 35

Steel grade 40

steel grade 45

APPENDIX4
Mandatory

PARAMETERS OF BRANDED STRIPS (LIMITS OF HARDNESS HRC (HRC 3) AND HRB VARIATIONS ON THE LENGTH OF THE END SAMPLE)

Table 9

Distance from the end, mm	Hardness for hardenability bands of steel grades


	HRC 56 (HRC, 57)	HRC 48 (HRC, 49.5)	HRC 57 (HRC, 58)	HRC 49 (HRC, 50.5)	HRC 58 (HRC, 59)	HRC 49 (HRC, 50.5)
	HRC 54 (HRC, 55)		HRC 56 (HRC, 57)	HRC 44 (HRC, 45.5)	HRC 56 (HRC, 57)	HRC 44 (HRC, 45.5)
	HRC 48 (HRC, 49)	HRC 25 (HRC, 27)	HRC 51 (HRC 52.2)	HRC 27 (HRC, 29)	HRC 53 (HRC, 54)	HRC 27 (HRC, 29)
	HRC 36 (HRC, 38)	HRC 21 (HRC, 23)	HRC 36 (HRC, 37.5)	HRC 24 (HRC, 26)	HRC 41 (HRC, 42.5)	HRC 24 (HRC, 26)
	HRC 29 (HRC, 31)	HRC 18 (HRC, 20)	HRC 32 (HRC, 33.5)	HRC 22 (HRC, 24)	HRC 35 (HRC, 36.5)	HRC 22 (HRC, 24)
	HRC 28 (HRC, 30)		HRC 30 (HRC, 32)	HRC 20 (HRC, 22)	HRC 31 (HRC, 33)	HRC 20 (HRC, 22)
	HRC 27 (HRC, 29)		HRC 28 (HRC, 30)	HRC 18 (HRC, 20)	HRC 30.5 (HRC 32.5)	HRC 19 (HRC, 21)
	HRC 26 (HRC, 28)		HRC 27 (HRC, 29)		HRC 29 (HRC, 31)
	HRC 25.5 (HRC 27.5)		HRC 26 (HRC, 28)		HRC 28 (HRC, 30)
	HRC 25 (HRC, 27)		HRC 25.5 (HRC 27.5)		HRC 27.5 (HRC 29.5)
	HRC 24.5 (HRC 26.5)		HRC 25 (HRC, 27)		HRC 27 (HRC, 29)
	HRC 24 (HRC, 26)		HRC 24.5 (HRC 26.5)		HRC 26.5 (HRC 28.5)
	HRC 23.5 (HRC 25.5)		HRC 24 (HRC, 26)		HRC 26 (HRC, 28)
	HRC 23 (HRC, 25)		HRC 23.5 (HRC 25.5)		HRC 25 (HRC, 27)
	HRC 22 (HRC, 24)		HRC 23 (HRC, 25)		HRC 24 (HRC, 26)
	HRC 21 (HRC, 23)		HRC 22 (HRC, 24)
	HRC 20 (HRC, 22)		HRC 21 (HRC, 23)		HRC 22 (HRC, 24)
			HRC 20.5 (HRC 22.5)
			HRC 20 (HRC, 22)

RENTAL CHARACTERISTICS SET BY AGREEMENT OF THE CONSUMER WITH THE MANUFACTURER IN NTD

1. Rolled products with a normalized mass fraction of nitrogen in electric steel.

2. Rental with a lower mass fraction of manganese, reduced against the norms of table. 1 per manganese equivalent value equal to:

E m \u003d 0.3 (Cr%) + 0.5 (Ni%) + 0.7 (Cu%), where Cr, Ni, Cu - the residual actual mass fraction of chromium, nickel, copper in steel, not exceeding the norms, indicated in the table. one.

3. Rolled stock calibrated from steel grades 08, 55 and 60 in cold-worked or heat-treated condition with control of mechanical properties.

4. Rolled products with normalized impact strength on specimens of type I at a temperature of minus 40 ºС.

5. Rolled products with normalized impact strength on samples of type II at a temperature of plus 20°C and sub-zero temperatures.

6. Rental without control of the relative narrowing.

7. Rolled products calibrated and with a special surface finish with a normalized hardness in a normalized with tempering and hardened with tempering state.

8. Rolled bars with normalized hardness in a normalized state.

9. Rolled products with normalized hardness within specified limits.

10. Rental without hardness control.

11. Rolled products with normalized austenite grain size.

12. Rolled products with standardized cleanliness for non-metallic inclusions.

13. Rolled products with standardized cleanliness according to hairlines detected on the surface of finished parts by the magnetic method or etching.

14. Rental of low-tonnage parties.

MODES
heat treatment of workpieces to control the mechanical properties given in table. 3 and 4

Table 10

steel grade	Heating temperature, ºС
	Normalization
	Tensile test	Impact test

during normalization or hardening - 30 min;

when tempering 200 ºС - 2 hours;

when tempering 600 ºС - 1 hour.

The cooling medium during quenching is water.

MODES
heat treatment of workpieces to control the mechanical properties given in table. eight

Table 11

steel grade
steel grade	Heating temperature, ºС	Cooling medium	Heating temperature, ºС
			Air cooling

		Water or oil


		Oil or water

APPENDIX 8
Mandatory

Scheme of sampling for determination of hardness after hardening

a - for rolled diameter b- for rolled diameter

up to 25 mm over 25 mm

Conventions

Cross section of the sample; sample length 55–60 mm.

B - platform for measuring hardness.

The modes of heat treatment of samples for determining the hardness after hardening, are given in table. 8a

Table 12

Notes:

1. Holding time during hardening (after reaching the hardening temperature) 20 min.

2. Oil temperature (65±10) ºС.

Appendices 8, 9. (Introduced additionally, ch. No. 1).

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Metallurgy of the USSR

DEVELOPERS

V. T. Ababkov, cand. tech. sciences (topic leader);

V. D. Khromov, cand. tech. sciences; N. I. Elina

2. APPROVED AND INTRODUCED BY Decree of the USSR State Committee for Standards dated 11/24/88 No. 3811

3. REPLACE GOST 1050-74

4. Validation period - 1997

5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

Number of paragraph, subparagraph, enumeration, application

GOST 8.001-80

GOST 8.326-89

GOST 162-90

7. REPUBLICATION with Amendment No. 1 approved December 1991
(IUS 4-92)

1. Main parameters and dimensions.. 1

2. Technical requirements. 3

3. Acceptance rules. eight

4. Test methods. eight

5. Transportation and storage. ten

Appendix 1 Examples of the symbol for rental. ten

Annex 2 Transformation of rectangular sections into round ones with the same mechanical properties. 12

Appendix 3 Structural hardenability bands carbon steel. 12

Appendix 4 Parameters of grade strips (limits of fluctuations in hardness hrc (hrc 3) and hrb along the length of the end sample) 15

Annex 5 Characteristics of rolled products, established by agreement between the consumer and the manufacturer in the ntd .. 16

Appendix 6 Modes of heat treatment of workpieces to control mechanical properties. sixteen

Annex 7 Modes of heat treatment of workpieces to control mechanical properties. 17

Appendix 8 Scheme of sampling for determination of hardness after hardening. 17

Appendix 9 Modes of heat treatment of samples for determining the hardness after hardening. 17

Substitutes for steel 20 are steel 15 and steel 25.

Designation of steels according to GOST 1050-88

When designating steel 20:

the word "steel" is written in full,
the number 20 is written separately (with a space),
point is not set.

For example, "steel 20" or exactly according to the standard "steel grade 20". This is the difference between the designations of structural carbon quality steels from according to GOST 380-2005. The number after the word "steel" indicates the nominal carbon content of the steel in hundredths of a percent. For steel 20, this is 0.20% carbon.

Unlike high-quality steels (steel 20, steel 25 and others), ordinary steels according to GOST 380-2005 are abbreviated, together and without a dot, for example, st3 or st4. If it’s completely according to the letter of the standard, then “steel grade St3”.

Steel 20: chemical composition

The chemical composition of steel 20 determines GOST 1050-88:

Steel structure 20

Typical structure of steel 20 - . 20 it is possible to obtain the lath martensite structure. Thermally hardened rolled steel 20 is used for the manufacture of hardware products (strength class 8.8).

Technological properties of steel 20

forging start temperature - 1280 ° C,
forging end temperature - 750 ° C,
forging cooling - air.

Not prone to flaking.

Not prone to temper brittleness.

Weldability of steel 20:

with no restrictions;
without preheating;
without further heat treatment.

Application of steel 20

From steel 20 they make:

lightly loaded parts (fingers, axles, copiers, stops, gears);
carburized parts for long-term operation, including at temperatures up to 350 ° C;
crane hooks;
bearing shells and other parts for operation under pressure at temperatures from minus 40 to 450 °C.

Steel 20 after chemical-thermal treatment is used for parts with high surface strength (worms, worm pairs, gears). Steel 20 is widely used for the production of pipeline fittings, steam pipelines, seamless pipes high pressure, welded rectangular and square profiles.

Types of steel supply 20

Types of steel supply 20:

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INTERSTATE STANDARD

RENTAL LOTS, CALIBRATED,
WITH SPECIAL FINISHES
CARBON SURFACES
OF QUALITY STRUCTURAL STEEL

GENERAL SPECIFICATIONS

Date of introduction 01.01.91

This standard establishes general specifications for hot-rolled and forged long products from carbon quality structural steel grades 08, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 58 (55pp) and 60 with a diameter or thickness up to 250 mm, as well as rolled products calibrated and with a special surface finish of all grades.

1. MAIN PARAMETERS AND DIMENSIONS

1.1. Grades and chemical composition of steel according to the ladle test must correspond to those given in table. one.

Table 1

steel grade	Mass fraction of elements, %
steel grade	carbon		manganese	chrome, no more
	Not more than 0.06	Not more than 0.03	Not more than 0.40
		Not more than 0.03


		Not more than 0.07


		Not more than 0.06
		Not more than 0.07


		Not more than 0.06
		Not more than 0.07









			Not more than 0.20

Notes:

1. According to the degree of deoxidation, steel is designated: boiling - kp, semi-calm - ps, calm - without an index.

2. Steel grade 05kp is not allowed for use in newly created and modernized equipment.

1.1.1. The mass fraction of sulfur in steel should be no more than 0.040%, phosphorus - no more than 0.035%.

For steel grades 11kp and 18kp used for cladding, the mass fraction of sulfur should be no more than 0.035%, phosphorus - no more than 0.030%.

1.1.2. The residual mass fraction of nickel in steel of all grades should not exceed 0.30%, copper in steel grades 11kp and 18kp - 0.20%, in steel of other grades - 0.30%.

1.1.3. In steel grades 35, 40, 45, 50, 55 and 60, intended for the manufacture of patented wire, the mass fraction of manganese should be from 0.30% to 0.60%, nickel - no more than 0.15%, chromium - no more 0.15%, copper - no more than 0.20%. The mass fraction of sulfur and phosphorus - in accordance with the requirements of the wire standards, but does not exceed the standards given in paragraph 1.1.1.

1.1.4. In steel grades 08ps, 10ps, 15ps and 20ps, intended for the manufacture of sheet metal for cold stamping, the mass fraction of manganese is allowed up to 0.25% at the lower limit.

1.1.5. In steel grades 08ps, 10ps, 15ps and 20ps, a silicon mass fraction of less than 0.05% is allowed, provided that other (except silicon) deoxidizers are used in the required quantities.

1.1.6. In steel, the mass fraction of arsenic is not more than 0.08%.

1.1.7. Mass fraction of nitrogen in oxygen-converter steel

1.1.7.1 For rolled products made from steel without out-of-furnace treatment, the mass fraction of nitrogen should not exceed:

0.006% - for sheet metal and strip;

0.008% - for other types of rolled products.

1.1.7.2 For rolled products made from steel with out-of-furnace processing, the mass fraction of nitrogen should not exceed 0.010%.

1.1.8. By agreement between the customer and the manufacturer, which is specified in the order, in calm steel made using scrap metal, a residual mass fraction of chromium and nickel is allowed not more than 0.40% each.

1.2. In rolled products, blanks, forgings and products of further processing, deviations in chemical composition from the norms given in Table 1 are allowed. 1, in accordance with the table. 2.

table 2

1.3. The range of rolled products must meet the requirements:

2. TECHNICAL REQUIREMENTS

2.1. Characteristics of the basic version

2.1.2. Rolled calibrated random (ND) length with maximum deviations for the tolerance field - h11, ovality - no more than the maximum deviations in diameter.

2.1.3. Rolled products with a special surface finish of random (ND) length with maximum deviations for the tolerance field - h11, ovality - no more than half of the maximum deviations in diameter.

2.1.5 Rolled long products of two groups of surface quality: 2GP and 3GP. Rolled products of surface quality group 2ГП are intended mainly for hot working by pressure, group 3ГП - mainly for cold machining.

2.1.6. On the surface of the rolled product of the surface quality group 2ГП there should be no rolled bubbles, rolling films, sunsets, cracks, pollution, stress cracks.

2.1.1-2.1.6.(Changed edition, Change No. 1).

2.1.6.1. Defects on the surface must be removed by a shallow cut or by grinding, the width of which must be at least five times the depth.

The depth of cleaning of defects, counting from the actual size, should not exceed:

half the sum of the maximum deviations for the size - for rolled products with a size of less than 80 mm;

the sum of the maximum deviations for the size - for rolled products with sizes from 80 to 140 mm;

5% of the diameter or thickness - for rolled products ranging in size from 140 to 200 mm;

6% - diameter or thickness - for rolled products larger than 200 mm.

In one section of rolled products with a size (diameter or thickness) of more than 140 mm, no more than two strippings of maximum depth are allowed.

2.1.6.2. On the surface of the rolled products, individual risks, dents and ripples with a depth of up to half the sum of the maximum deviations per size, as well as rolled bubbles and pollution (hairs) with a depth not exceeding 1/4 are allowed without stripping. the sum of maximum deviations per size, but not more than 0.20 mm, counting from the actual size.

2.1.7. On the surface of rolled products with a surface quality of group 3ГП, local defects are allowed with a depth not exceeding the minus limit deviation for a size for rolled products with a size of less than 100 mm; the sum of the maximum deviations for the size - for rolled products with a size of 100 mm or more.

Depth of defects is calculated from the nominal size.

2.1.8. Rolled products must be cut off.

Wrinkled ends and burrs are allowed.

The oblique cut of long products up to 30 mm in size is not regulated, over 30 mm - it should not exceed 0.1 diameter or thickness. Bars up to 40 mm in size of random length are allowed to be produced with unedged ends.

2.1.9. Surface quality and requirements for trimming the ends of calibrated rolled products must comply with - GOST 1051 groups B and C, with a special surface finish - GOST 14955 groups C, D and D.

In rolled products with a special surface finish, decarburization is not allowed.

2.1.10. Hardness (ТВ1) of long products without heat treatment should not exceed 255 HB, calibrated and with a special surface finish of hard-worked - 269 HB.

2.1.11. The mechanical properties of rolled products in the normalized state (Ml) must comply with the standards given in Table. 3.

Table 3

steel grade	Mechanical properties, not less than
	Yield strength σ t N / mm 2 (kgf / mm 2)	Elongation δ	Relative contraction ψ
	Yield strength σ t N / mm 2 (kgf / mm 2)

Notes:

2. By agreement between the manufacturer and the consumer for steel grades 25-60, a reduction in tensile strength by 20 N / mm 2 (2 kgf / mm 2) is allowed compared to the standards indicated in table. 3, while increasing the rate of elongation by 2% (abs.).

2.1.12. The macrostructure of rolled steel should not have a shrinkage cavity, friability, bubbles, delaminations, internal cracks, slag inclusions and flocs.

2.2. User Defined Characteristics

2.2.1. Rolled steel grades 20, 25, 30, 35, 40, 45, 50 with a mass fraction of boron from 0.002% to 0.006%.

In this case, the letter R is placed at the end of the brand designation.

2.2.2. Rolled steel from calm steel with a mass fraction of silicon from 0.17% to 0.27%.

2.2.1, 2.2.2(Revised edition, Rev. No. 2).

2.2.3. Rental of measured (MD) lengths.

2.2.4. Rolled length, multiple dimensional (KD).

2.2.5. Rolled products calibrated and with a special surface finish with tolerance h12.

2.2.6. Long products in a heat-treated state (annealed, high-tempered, normalized, normalized with tempering) - TO.

2.2.7. Rolled products with a surface quality of group 1ГП - for rolled bubbles and impurities (hairs) and a hot upset test (65).

Rolled products are mainly intended for hot upsetting, upsetting and stamping.

2.2.8. Rolled steel grades 25, 30, 35, 40, 45, 50 with control of impact strength (IUV) on heat-treated (quenching + tempering) samples.

The norms of impact strength (U B) must correspond to those indicated in Table. 4.

Table 4

2.2.9. Rolled products calibrated in cold-worked or heat-treated state with normalized mechanical properties (M2) in accordance with the requirements specified in Table. 5.

Table 5

steel grade	Mechanical properties of rolled products, not less than
	cold-worked
		Relative elongation δ,%	Relative contraction ψ,%	Tensile strength σ t, N / mm 2 (kgf / mm 2)	Relative elongation δ,%	Relative contraction ψ,%

2.2.10. Rolled products with a macrostructure normalized in points (KMS) in accordance with the requirements specified in Table. 6.

Table 6

Note. For rolled products with a size of 70 mm or more with a surface quality of group 3ГП, subcrustal bubbles of grade 2 are allowed to a depth of not more than 1/2, the sum of maximum deviations per diameter or thickness.

2.2.11. Rolled products with normalized hardness (TV2) in accordance with the requirements given in Table. 7.

Table 7

steel grade	Hardness number HB, no more
	for hot-rolled and forged steel		for calibrated steel and with special surface finish
	without heat treatment	after annealing or high tempering	cold-worked	annealed or highly tempered

2.2.12. Rolled products with ultrasonic control (UT) of internal defects in accordance with GOST 21120.

2.2.13. Rolled steel grades 08, 10, 15 and 20 with weldability (HS).

For rolled steel of other grades, in order to ensure weldability, the customer specifies the carbon equivalent formula in the order or specifies the chemical composition of the steel.

2.2.14. Rolled steel grades 35, 40, 45, 50, 55, 58 (55pp), 60, intended for surface hardening by high frequency currents, with decarburization (ferrite + transition zone) not more than 1.5% of the diameter or thickness per side (1С ).

2.2.4 - 2.2.14 (Revised edition, Rev. No. 1).

2.2.15 Rolled steel grade 50 with a mass fraction of sulfur and phosphorus not more than 0.025% each. In this case, the brand designation is 50A

2.3. Characteristics established by agreement between the consumer and the manufacturer

2.3.1. Rental with reduced compared to those given in table. 1 limits by mass fraction of carbon, but not less than 0.05%.

2.3.2. Rental with reduced compared to those given in table. 1 limits for the mass fraction of carbon, but not less than 0.05%, without taking into account the permissible deviations in the finished rolled products indicated in Table. 2.

2.3.3. Rolled products with a mass fraction of sulfur from 0.020% to 0.040%.

2.3.4. Rolled products with mass fraction of sulfur not more than 0.025%.

2.3.5. Rolled products with a mass fraction of phosphorus not more than 0.030%.

2.3.6. Rolled products with a mass fraction of copper not more than 0.25%.

2.3.7. Long products with a diameter or thickness over 30 to 140 mm with the removal of burrs (US) and crumpled ends.

2.3.8. Hard-worked steel with an increase of 15 HB compared to that shown in table. 7 hardness (TV3).

2.3.9. Rolled products with normalized mechanical properties (M3) determined on samples cut from heat-treated blanks (quenching + tempering) of the size specified in the order, in accordance with the requirements of Table. eight.

Table 8

steel grade

Mechanical properties of rolled products

from 16 to 40 mm

from 40 to 100 mm

Tensile strength σ in N/mm 2 (kgf/mm 2)

Impact work KU, J (kgf. m)

Yield strength σ t N / mm 2 (kgf / mm 2) not less than

Tensile strength σ in N/mm 2 (kgf/mm 2)

Relative elongation δ 5 %

Impact work KU, J (kgf. m)

Yield strength σ t N / mm 2 (kgf / mm 2) not less than

Tensile strength σ in N/mm 2 (kgf/mm 2)

Relative elongation δ 5 %

Impact work KU, J (kgf. m)

Notes:

2. The mechanical properties of steel 30 apply to rolled products up to 63 mm in size.

3. The values of mechanical properties are given for rolled products of round section. For rectangular sections, the ranges of equivalent diameters are given in Appendix 2.

2.3.10. Rolled products with normalized hardenability (PR) in accordance with Appendix 4.

2.3.9, 2.3.10(Changed edition,Change No. 2 ).

2.3.11. Rolled steel grades 35, 40, 45, 50, 55, 58 (55pp), 60, intended for surface hardening by high frequency currents, with decarburization (ferrite + transition zone) not more than 0.5% of the diameter or thickness per side (2С ).

2.3.12. Rental in pickled (T) condition.

2.3.6 - 2.3.12.(Changed edition,Change No. 1 ).

2.3.13. Rolled products calibrated with tolerance field h10.

2.3.14. High-quality hot-rolled steel of increased (B) and high (A) dimensional accuracy.

2.3.15. Rolled products with a surface quality of group 2ГП with a hot upset test (65).

Testing of rolled products with the size of St. 80 mm may be omitted by the manufacturer.

2.3.16. Rolled steel grades 45, 50, 50A with hardness control (TV4) on hardened samples in accordance with the requirements specified in table. 8a.

Table 8a

2.3.17. The mass fraction of nitrogen is not more than 0.008% in oxygen-converter steel for thin-sheet rolling.

2.3.13 - 2.3.17. (Introduced additionally, Amendment No. 1).

2.4. It is allowed in the technical specifications for specific products to provide for additional or enhanced characteristics that are not provided for by this standard.

The list of additional characteristics is given in Appendix 5.

2.5. Marking and packaging of rolled products - according to GOST 7566.

2.5.1. Packing of calibrated rolled products - in accordance with GOST 1051, with a special surface finish - in accordance with GOST 14955.

2.5.2. The marking is applied directly to the product if the product is not subject to packaging, and on the label if the product is packed in bundles, coils and coils.

3. ACCEPTANCE RULES

3.1. Rolled products are accepted in batches consisting of steel of the same heat, one size and one heat treatment mode (when manufactured in a heat-treated state).

By agreement between the manufacturer and the consumer, the parties are formed from steel of the same brand of several heats of the same size.

Each batch is accompanied by a quality document in accordance with GOST 7566.

When using deoxidizers other than silicon for semi-quiet steel, a corresponding indication is made in the quality document.

For rental, accepted with the characteristics set by the consumer in accordance with paragraphs. 2.2 and 2.3, the quality document indicates the test results for ordered indicators.

3.2. The rental is subjected to acceptance tests.

3.3. To check the quality of the batch of rolled products are selected:

1) for chemical analysis - samples according to GOST 7565. The manufacturer carries out control of residual copper, nickel, chromium, arsenic and nitrogen periodically at least once a quarter. In the manufacture of steel, taking into account the manganese equivalent, the control of residual copper, nickel and chromium is carried out on each heat;

2) to control the quality of the surface and dimensions - all bars, strips and coils;

3) to control the macrostructure by fracture or etching, to test for impact bending, to determine the depth of the decarburized layer - two rods, strips or coils;

4) to test the hardness - 2% bars, strips or coils, but not less than 3 pieces;

7) to determine the size of the grain - one rod, strip or coil from the melting ladle;

8) for the draft test - three bars, strips or coils;

9) to determine the hardness after hardening - two longitudinal samples from the melt.

3.4. Upon receipt of unsatisfactory test results for at least one of the indicators, it is retested in accordance with GOST 7566.

The results of repeated tests are extended to the entire batch.

4. TEST METHODS

4.1. Chemical analysis of steel is carried out according to GOST 22536.0 - GOST 22536.9, GOST 27809, GOST 12359 or other methods in terms of accuracy that are not inferior to standard ones. In case of disagreement, chemical analysis is carried out in accordance with GOST 22536.0 - GOST 22536.9, GOST 27809, GOST 12359.

4.2. The quality of the surface is checked by inspection of the rolled products without the use of magnifying devices. If necessary, the surface is brightened or etched, and for rolled products with a special surface finish with a diameter of up to 3 mm inclusive, the inspection is carried out at a magnification of up to 10 × . The depth of occurrence of defects on the surface of the rolled products is determined by control cleaning or filing with a file.

4.3. The geometric dimensions and shape are determined using measuring instruments according to GOST 26877, GOST 162, GOST 166, GOST 427, GOST 3749, GOST 5378, GOST 6507, GOST 7502, or instruments that have been verified or calibrated.

4.4. Sampling from coils for all types of tests is carried out at a distance of at least 1.5 turns from the end of the roll.

for impact bending testing - one sample of each type;

to control the macrostructure - one template.

4.6. Sampling for draft tests - according to GOST 7564.

4.7. Sampling for testing mechanical properties according to table. 3 and 5 are carried out according to GOST 7564 (option 1), according to the table. 4 and 8 - according to GOST 7564 (option 2).

4.7a. Sampling for determination of hardness after hardening is carried out according to the scheme given in Appendix 8.

Samples for control can be cut out from finished rolled products or pig billets (in melting control).

Samples are heated to a forging temperature from 850 ºС to 1000 ºС and upset by 65% relative to the original height. On upset samples there should be no cracks and sunsets.

4.9. Brinell hardness is determined according to GOST 9012. The hardness of rolled products with a diameter or thickness of less than 5 mm is not determined.

4.9a. Rockwell hardness after hardening is determined according to GOST 9013 on a site located in the middle of the sample length. The surface of the platform for measuring hardness is subjected to stripping; while the surface roughness Ra should be no more than 1.25 microns according to GOST 2789.

4.10. The tensile test is carried out according to GOST 1497 on samples of five times the length with a diameter of 5 or 10 mm.

For rolled products with a diameter or thickness up to 25 mm inclusive, the test may be carried out on samples without machining.

The impact test is carried out according to GOST 9454 on specimens of type 1 or 11.

The sample axis direction is along the rolling direction.

4.11. For tensile tests of rolled products in accordance with the requirements of Table. 3 samples for rolled products without heat treatment and for heat-treated rolled products (except normalized) are cut from normalized billets with a diameter (square side) of 25 mm. For rolled products less than 25 mm in size, normalization is carried out in the finished section, without cutting the workpiece.

Note - From bars larger than 120 mm, sampling for mechanical tests can be carried out from reforged or rolled blanks with a section size of 90 - 100 mm.

For normalized rolled products, a tensile test is carried out on samples made from blanks with a diameter (square side) of 25 mm, taken from rolled products in the delivery condition.

4.12. for tensile tests, rolled products in accordance with the requirements of Table 8 are cut from heat-treated billets. The size of the workpiece is specified by the consumer. If there is no workpiece size in the order, it is selected by the manufacturer and indicated in the quality document.

4.13. The modes of heat treatment of blanks (samples) for testing mechanical properties are given in Appendices 6 and 7, for hardness control after hardening - in Appendix 9.

4.14. The control of the macrostructure for fracture or etched templates is carried out without the use of magnifying devices according to GOST 10243.

It is allowed to use ultrasonic testing methods (UT) and other non-destructive testing methods agreed upon in the prescribed manner.

4.15. The depth of the decarburized layer is determined according to GOST 1763.

4.16. Hardenability is determined by the method of end hardening according to GOST 5657.

4.17. The grain size is determined according to GOST 5639.

4.18. On steel of the same heat, which has passed tests for macrostructure, hardenability and mechanical properties on large rolled sections, in the manufacture of smaller rolled sections, the listed tests at the manufacturer may not be carried out.

5. TRANSPORT AND STORAGE

5.1. Transportation and storage - according to GOST 7566 with the following addition.

5.1.1. Transportation of products is carried out by transport of all types in accordance with the rules for the carriage of goods in force for this type of transport. By rail, transportation is carried out depending on the weight and overall dimensions in covered or open wagons. The mass of a package should not exceed 10,000 kg for mechanized loading into open vehicles, and 1,250 kg into covered vehicles. Packaging, means and methods for forming packages - according to GOST 7566.

APPENDIX 1
Mandatory

EXAMPLES OF RENTAL SYMBOLS

Scheme 1 of the rental symbol

In the design documentation, it is allowed to give examples of symbols in accordance with scheme 2.

Legend Examples

Rolled bars, round, of ordinary rolling hardness (B1), class II in terms of curvature, random length (ND), diameter 100 mm according to GOST 2590, made of steel grade 30, with surface quality of group 2GP, with mechanical properties according to table. 3 (M1), with hardness according to clause 2.1.10 (TB1), with impact strength control according to table. 4 (EFS), with deburring (US), with hot upset test (65), without heat treatment:

Rolled bars, square, increased rolling accuracy (B1), class I in terms of curvature, measured length (MD), with a square side of 25 mm in accordance with GOST 2591, from steel grade 35, with a surface quality of group 1GP, with mechanical properties according to table. 8 (M3), with hardness according to table. 7 (TV2), with a macrostructure normalized in points (MCS) according to Table. 6, with decarburization according to paragraph 2.2.14 (1C), heat treated (HT):

Rolled strip, normal accuracy of rolling in thickness (VT1) and width (VSh1), normal crescent shape (VS), normal flatness (PN), multiple measured length (KD), general purpose (OH), 36 mm thick, 90 mm wide GOST 103, from steel grade 45, with surface quality of the ZGP group, with mechanical properties according to table. 3 (Ml), with hardness according to clause 2.1.10 (TV1), with normalized hardenability (PR), without heat treatment:

Strip VT1-VSh1-VS-PN-KD-ON-36×90 GOST 103-2006 /45-3GP-M1-TV1-PR GOST 1050-88

Hot-rolled profile for oblique washers, measured length (MD), with dimensions 2B´H´h=32´5.8´4 mm according to GOST 5157, made of steel grade 35, with surface quality of group 3ГП, with mechanical properties according to Table. 3 (Ml), with hardness according to clause 2.1.10 (TB1), without heat treatment:

Profile for oblique washers MD-32´5,8´4 GOST 5157-83 /35-3GP-M1-TB1 GOST 1050-88

Rolled calibrated, round, with a tolerance field according to h11, measured length (MD), with a diameter of 10 mm according to GOST 7417, made of steel grade 45, with a surface quality of group B according to GOST 1051, with mechanical properties according to Table. 5 (M2), with hardness according to clause 2.3.8 (TB3), with decarburization according to clause 2.3.11 (2C), hard-worked (NG):

Rolled calibrated, square, with a tolerance field h11, multiple measured length (KD), with a square side of 15 mm in accordance with GOST 8559, made of steel grade 20, with a surface quality of group B in accordance with GOST 1051, with mechanical properties according to Table. 8 (M3), with hardness according to table. 7 (TV2), with ensuring weldability (HS), hard-worked (NG):

Rolled stock calibrated, hexagonal, with a tolerance field h12, random length (ND), an inscribed circle diameter of 8 mm according to GOST 8560, made of steel grade 45, with a surface quality of group B according to GOST 1051, with mechanical properties according to Table. 3 (Ml), with hardness according to table. 8a (TB4), heat treated (TO):

Rolled products with a special surface finish, round, with a tolerance field h11, random length (ND), diameter 8 mm, surface quality group B according to GOST 14955 from steel grade 20, with mechanical properties according to table. 5 (M2), with hardness according to table. 7 (TVZ) hard-worked (NG):

Examples of symbols that are allowed to be given in the design documentation:

Rolled products with a special surface finish, round, with a tolerance field h11, random length (ND), diameter 8 mm, surface quality group B according to GOST 14955, made of steel grade 20, with mechanical properties according to table. 5 (M2), with hardness according to table. 7 (TVZ), hard-worked (NG):

APPENDIX 1.(Changed edition, Rev. No. 1, Amendment , ).

APPENDIX 2
Mandatory

CONVERSION OF RECTANGULAR SECTIONS TO ROUND AT ONE
AND THE SAME MECHANICAL PROPERTIES

APPENDIX 3(Deleted, Rev. No. 2).

APPENDIX4
Mandatory

PARAMETERS OF STANDARD STRIPS (LIMITS OF SWITCH
HARDNESSHRC and HRB BY THE LENGTH OF THE END SAMPLE)

Table 9

Distance from the end, mm	Hardness for hardenability bands of steel grades

GOST 1050-88 establishes general specifications for hot-rolled and forged long products made of quality carbon structural steel grades 08, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 58 (55pp) and 60 with a diameter or thickness up to 250 mm , as well as rolled products calibrated and with a special surface finish of all grades.
In terms of chemical composition, GOST 1050-88 applies to other types of rolled products, ingots, forgings, stampings from steel of the grades listed above, as well as from steel grades 05kp, 08kp, 08ps, 10kp, 10 ps, 11kp, 15kp, 15ps, 18kp , 20kp and 20ps.

Steel 20 GOST 1050 88 mechanical properties. Rolled bars, calibrated, with a special surface finish from quality carbon structural steel

Steel 20. Application in production.

Chemical composition of Steel 20.

Steel 20 GOST.

Steel 20. Mechanical properties.

Mechanical characteristics at elevated temperatures

Mechanical properties of Steel 20 at a temperature of +20C.

Mechanical properties of forgings

Mechanical properties of steel after chemical-thermal treatment.

Technological properties of Steel 20

impact strength.

Impact strength KCU (J/cm3) at low temperatures °С

endurance limit

Physical properties of steel 20

APPENDIX 1Mandatory

APPENDIX 2Mandatory

APPENDIX 3Mandatory

APPENDIX4Mandatory

APPENDIX 8Mandatory

Designation of steels according to GOST 1050-88

Steel 20: chemical composition

Steel structure 20

Technological properties of steel 20

Application of steel 20

Types of steel supply 20

1. MAIN PARAMETERS AND DIMENSIONS

2. TECHNICAL REQUIREMENTS

3. ACCEPTANCE RULES

4. TEST METHODS

5. TRANSPORT AND STORAGE

APPENDIX 1 Mandatory

APPENDIX 2Mandatory

APPENDIX 3(Deleted, Rev. No. 2).

APPENDIX4 Mandatory

APPENDIX 1
Mandatory

APPENDIX 2
Mandatory

APPENDIX 3
Mandatory

APPENDIX4
Mandatory

APPENDIX 8
Mandatory

APPENDIX 1
Mandatory

APPENDIX 2
Mandatory

APPENDIX4
Mandatory