Is p6m5 steel high-alloy. Steel R6M5: characteristics, application

Manganese as an alloying element

Tungsten iron

R6M5 characteristics

The composition of steel R6M5

Characteristics of high speed steels

Deciphering the designation of steel grades

Production and processing methods

Product Performance Improvement

home Business Is p6m5 steel high-alloy. Steel R6M5: characteristics, application

An alloy of an element of the eighth group of the periodic system of Mendeleev with atomic number 26 (iron) with carbon and some other elements is commonly called steel. It has high strength and hardness, devoid of plasticity and viscosity due to carbon. increase the positive characteristics of the alloy. Nevertheless, steel is considered to be a metal material that contains at least 45% iron.

Consider an alloy such as R6M5 steel, and find out what characteristics it has and in what areas it is used.

Until the 19th century, ordinary steel was used to process non-ferrous metals and wood. Its cutting characteristics were quite enough for this. However, when trying to process steel parts, the tool heats up very quickly, wears out and even deforms.

The English metallurgist R. Muschette, through experiments, found out that in order to make the alloy more durable, it is necessary to add an oxidizing agent to it, which will release excess oxygen from it. In the cast add mirror cast iron, which contained manganese. Since it is an alloying element, its percentage should not exceed 0.8%. So, R6M5 steel contains from 0.2% to 0.5% manganese.

Already in 1858, many scientists and metallurgists were working on obtaining alloys with tungsten. They knew for sure that it was one of the most refractory metals. Adding it to steel as an alloying element made it possible to obtain an alloy that could withstand high temperatures and still not wear out.

It is also used for the production of heat-resistant ball bearings operating at high speed at a temperature of 500-600°C. The analogues of the R6M5 alloy are R12, R10K5F5, R14F4, R9K10, R6M3, R9F5, R9K5, R18F2, 6M5K5. If tungsten-molybdenum alloys, as a rule, are used for the manufacture of tools for roughing (drills, cutters), then vanadium (R14F4) for finishing (reamers, broaches). Each cutting tool must have a marking that allows you to find out what alloy it is made of.

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Steel P6M5 - high-speed tool steel. It is applied to the cutting tools working in the conditions of considerable loading and heating of working edges. High speed steel tools are highly stable and are well suited for making kitchen, camping or folding knives. Steel R6M5 has practically replaced steels R18, R12 and R9 with similar properties and has found application in the processing of non-ferrous alloys, cast irons, carbon and alloy steels, as well as some heat-resistant and corrosion-resistant steels.

Deciphering steel R6M5

The letter "P" is the designation of high-speed steels. The word is taken from the transcription of the English "rapid", which translates as "fast".

The number behind the letter "P" indicates the percentage of tungsten in the alloy (6%)

In addition to Mo, high-speed steels may contain the following designations in their marking: "K" - cobalt, "F" - vanadium, "T" - titanium, "C" - zirconium.

This steel grade has a rather complex composition and is not easy to manufacture. Not all knife manufacturers can work with P6M5 steel. And the price of the finished product comes out, as a rule, quite "biting". But knives made of R6M5 steel have exceptional qualities. The cutting edge of the knife made of this steel keeps sharpening for a long time. Knives have excellent cutting quality. With very high hardness, the steel has good ductility, which makes the knife very durable.

Basically, knives with a fixed blade of the Finca type are made from this steel. Due to its increased hardness, steel is not used for the manufacture of axes and machetes.

In addition, steel is heat resistant. A knife made of P6M5 can be sharpened on a machine without the risk of overheating the cutting edge.

The disadvantages of this steel include its weak anti-corrosion properties and the difficulty of sharpening.

For a beginner, I would not recommend a knife made of R6M5 steel. It is really difficult to sharpen it, as a rule, special elbor discs are used for high-quality sharpening (a superhard material, close to diamond in properties). But if you need incredible "power" and reliability, then this is a good choice.

A knife made of R6M5 steel is not a toy, it is a very serious thing, ready for serious tests.

The hardness of steel R6M5 - 62-65 RHC

Carbon (C) 0.82 - 0.90%

Manganese (Mn) 0.20 - 0.50%

Chromium (Cr) 3.8 - 4.4%

Silicon (Si) 0.20 - 0.50%

Vanadium (V) 1.7 - 2.1%

Cobalt (Co) 0.5%

Such a material as high-speed steels has unique properties, which makes it possible to use it for the manufacture of tools with increased strength. The characteristics of high-speed steels make it possible to produce tools for various purposes from them.

The category of high-speed steels includes alloys, the chemical composition of which is supplemented with a number of alloying additives. Thanks to such additives, steels are given properties that allow them to be used for the manufacture of cutting tools that can work efficiently at high speeds. What distinguishes high-speed alloys from conventional carbon alloys is that the tool that is made from them can be successfully used for processing hard materials at high speeds.

The most remarkable characteristics that distinguish high-speed steels of various grades include the following.

Hot hardness (hot hardness). As you know, any tool used to perform cutting, in the process of such processing heats up intensely. As a result of heating, conventional tool steels are tempered, which ultimately leads to a decrease in tool hardness. This does not happen if high-speed steel was used for manufacturing, which is able to maintain its hardness even when the tool is heated up to 6000. Typically, high-speed steel grades, which are often called high-speed cutters, have even lower hardness compared to conventional carbon steels if the cutting temperature is within normal limits: up to 2000.
Increased redness. This parameter of any metal characterizes the period of time during which a tool made from it is able to withstand high temperatures without losing its original characteristics. High-speed steels as a material for the manufacture of cutting tools have no equal in this parameter.
Breakdown resistance. The cutting tool, in addition to the ability to endure exposure to elevated temperatures, must also be distinguished by improved mechanical characteristics, which is fully demonstrated by high-speed steel grades. A tool made of such steels, which has high strength, can successfully operate at large depths of cut (drills) and at high feed rates (cutters, drills, etc.).

Initially, high speed steel as a material for the manufacture of cutting tools was invented by British specialists. Taking into account the fact that a tool made of such steel can be used for high-speed metal processing, this material was called "rapidsteel" (the word "rapid" here just means high speed). This property of these steels and the English name invented by him at one time caused the designations of all grades this material start with the letter "R".

The rules belonging to the category of high-speed cutting are strictly regulated by the relevant GOST, which greatly simplifies the process of their decoding.

The first digit after the letter P in the designation of steel indicates the percentage in it of such an element as tungsten, which largely determines the main properties of this material. In addition to tungsten, high-speed steel contains vanadium, molybdenum and cobalt, which are designated in the marking, respectively, by the letters F, M and K. After each of these letters, there is a number in the marking indicating the percentage of the corresponding element in the chemical composition of the steel.

Depending on the content of certain elements in the steel composition, as well as on their quantity, all such alloys are divided into three main categories. It is quite easy to determine which category steel belongs to by deciphering its marking.

So, high-speed steel grades are usually divided into the following categories:

alloys containing up to 10% cobalt and up to 22% tungsten; such steels include alloys of grades R6M5F2K8, R10M4F3K10, etc.;
steels containing no more than 5% cobalt and up to 18% tungsten; such steels are alloys of grades R9K5, R18F2K5, R10F5K5, etc.;
alloys in which both cobalt and tungsten contain no more than 16%; such alloys include steel R9, R18, R12, R6M5, etc.

As mentioned above, the characteristics of steels belonging to the category of high-speed cutting are mainly determined by the content in them of such an element as tungsten. It should be borne in mind that if the high-speed alloy contains too much tungsten, cobalt and vanadium, then due to the formation of carbide inhomogeneity of such steel, the cutting edge of the tool that is made of it may chip under the influence of mechanical loads. Such shortcomings are deprived of tools made of steels containing molybdenum in their composition. The cutting edge of such tools not only does not crumble, but also differs in that it has the same hardness values along its entire length.

Steel grade for the manufacture of tools, which are subject to increased requirements for their technological characteristics, is P18. With a fine-grained internal structure, this steel exhibits excellent wear resistance. The advantage of using steel of this grade is also the fact that when hardening products from it, they do not overheat, which cannot be said about high-speed alloys of other grades. Due to the rather high cost of tools made from steel of this grade, it is often replaced with a cheaper P9 alloy.

The rather low cost of R9 steel, as well as its varieties - R9K5, which in its characteristics is in many respects similar to the high-speed alloy R18, is explained by a number of disadvantages of this material. The most significant of them is that in the annealed state such a metal is easily plastically deformed. Meanwhile, R18 steel is also not without drawbacks. So, high-precision tools are not made from this steel, which is explained by the fact that products from it are difficult to grind. Good indicators of strength and ductility, including in a heated state, are demonstrated by tools made of P12 steel, which is also similar in its characteristics to P18 steel.

For the production of tools made from high-speed alloys, two main technologies are used:

the classical method, which involves pouring molten metal into ingots, which are then subjected to forging;
a method of powder metallurgy in which molten metal is sprayed with a nitrogen jet.

The classical technology, which involves forging a product from a high-speed alloy, which was previously cast into a special shape, makes it possible to endow such a product with higher quality characteristics.

This technology helps to avoid the formation of carbide segregations in the finished product, and also makes it possible to subject it to preliminary annealing and further hardening. Besides, this technology manufacturing avoids the phenomenon of "naphthalene fracture", which leads to a significant increase in brittleness finished product made of high speed alloy.

hardening ready tools made of a high-speed alloy, is carried out at temperatures that contribute to better dissolution of alloying additives in them, but at the same time do not lead to grain growth. internal structure. After hardening, high-speed alloys have up to 30% austenite in their structure, which does not have the best effect on the thermal conductivity of the material and its hardness. In order to reduce the amount of austenite in the alloy structure to the minimum values, two technologies are used:

carry out several cycles of heating the product, holding at a certain temperature and cooling: repeated vacation;
before tempering, the product is cooled to a sufficiently low temperature: up to -800.

steel grade

R18K8F2M (EP 379)

In order for tools made of high-speed alloys to have high hardness, wear resistance and corrosion resistance, their surface must be subjected to processing, the methods of which include the following.

Heat-resistant high-hardness steels, called high-speed or high-speed cutters, are a group of high-alloy tool steels, which due to the composition and special regimes heat treatment for secondary hardness has a very high wear and red hardness (up to 550 - 600°C). They combine heat resistance (600-700°C) with high hardness (HRC 63-70) and increased resistance to plastic deformation. As a result of the application high speed steels it became possible to increase the cutting speed by 2-4 times (and even 5-6 times for newer steels with intermetallic hardening) and increase tool life by 10-40 times or more compared to those obtained for tools made of non-heat-resistant steels. These advantages are manifested when cutting: at an increased speed, i.e. under conditions of heating of the cutting edge, or at a lower speed, but with high pressure. To understand the features of the properties and the scope of their use, it is important that the decrease in their hardness by HRC 2-4 compared to the maximum obtained may be accompanied by a deterioration in toughness, strength and wear resistance. high speed steel necessary in use in a state of high hardness and when working without large dynamic loads.

The heat resistance of the quick cutter is created by special alloying and hardening with very high temperatures: 1200-1300˚C. The main alloying elements are tungsten or tungsten along with molybdenum.Numerous high-speed steels should be distinguished by the main property: moderate, high and high heat resistance. Steels of moderate and increased heat resistance have a relatively high carbon content (≥0.6-0.7%) and the same nature of hardening; secondary hardness is created by the release of carbides during tempering.

High speed steel of moderate heat resistance retain hardness HRC 60 after heating (4h) to 615-620˚C. They are suitable for cutting steels and cast irons with hardness up to HB 250-280, i.e. most structural materials, and are used most widely (78-80% of the total production of high-speed steels). Characteristic representatives of this group are P18 steels and more rationally alloyed: tungsten (P12 steel) and tungsten-molybdenum (P6M5 steel).

Steels of increased heat resistance have a high content of either carbon (nitrogen) or they are additionally alloyed with cobalt. They retain a hardness of HRC 60 after being heated to 630-650°C. The tool life, when properly used, of these steels is 1.5-4 times higher than that of steels of moderate heat resistance.

High heat resistance steels retain a hardness of HRC 60 after being heated to 700-730˚C. The nature of their hardening is fundamentally different - due to the release of intermetallic compounds. These steels, when used correctly, for example, for cutting many hard-to-cut materials, provide an increase in tool life by a factor of 10-15 or more.

1. Chemical composition of high-speed steels (GOST 19265-73)

steel grade











Notes: 1. The content of Mn, Si and Ni is not more than 0.4%; S and P not more than 0.03% (for steels R9F5, R14F4 and R10K5F5 0.035% P is allowed). 2. The content of molybdenum is allowed up to 1% in steel R18 and up to 0.6% in steel R9 (grades R18M and R9M). With an increase in the Mo content in R18M and R9M steels above 0.3%, the W content can be reduced in them (1% Mo replaces 2% W).

By composition, high-speed steel is divided into tungsten (R9, R12, R18, R18F2), high-vanadium (R9F5, R14F4), cobalt (R9K5, R9K10), cobalt-vanadium (R10K5F5, R18K5F2). Low-alloyed high-speed steels R7T, tungsten-molybdenum (R6M3 and R6M5F, cobalt-vanadium R6M3K5F2, R9M4K5F2 and R18K8F2M, etc.)

2. Chemical composition of high-speed steels (non-guested)

Range of manufactured high-speed steels:

hot-rolled and forged bars - round and square, strip;

round bars with increased surface finish and increased dimensional accuracy;

cold rolled tape.

3. Main properties of high speed steels in the initial state of delivery

steel grade	BUTr1	Temperature in °C	Weight % carbide phase
steel grade	BUTr1		Weight % carbide phase












Note. Cooling after annealing is carried out together with the furnace at a speed of not more than 30 ° /

Appointment of high speed steels

steel grade	Features and operating conditions of the tool	Purpose
	Tool with high wear resistance, retains cutting properties when heated during operation up to 600 ° C	Cutters, drills, cutters, cutters, reamers, countersinks, taps, broaches
	Works when the cutting edge is heated up to 600°C, does not require significant grinding and sharpening. It is possible to use methods of hot plastic deformation and induction hardening.	Cutters, drills, milling cutters, saws, woodworking tools, hacksaws
	Operates when the cutting edge is heated up to 600°C, a significant amount of grinding is possible. Hot plastic deformation can be applied	Cutters, drills, cutters, cutters, reamers, taps, broaches, dies
	Works when heated up to 580-600°C, with high feed rates under conditions of increased mechanical and shock loads. It is possible to use hot plastic deformation methods	Cutters, hobs, drills, broaches, machine taps
	A tool with a slightly higher productivity and wear resistance compared to steels P9 and P18 when machining medium-hard materials, stainless and heat-resistant alloys
	A tool with increased wear resistance, working in finishing operations with low feeds when processing steels of increased hardness, heat-resistant alloys, plastics, fiber, ebonite. Very bad sanding	Broaches, reamers
	Tool with increased wear resistance for machining high-strength materials and high-temperature alloys and plastics with hard inclusions. Very bad sanding	Cutters, milling cutters, worm cutters, segments for saws
	A tool with increased productivity, red hardness and hot hardness compared to P18 steel for machining heat-resistant, titanium alloys and other hard-to-cut materials. Steel prone to decarburization	Cutters, milling cutters, hobs, insert knives, special drills
	Tool with increased productivity, red hardness and wear resistance for machining hard-to-cut materials, high-temperature and titanium alloys. Steels are poorly ground and prone to decarburization	Cutters, worm cutters, knives for assembly cutters, drills
	Tool with increased wear resistance and toughness for machining titanium and heat-resistant alloys, stainless and high-strength steels	Cutters, drills, reamers, taps, gear cutting tools

Used for production metal cutting tool designed for high speed cutting. Alloying high-speed steels with tungsten, molybdenum, vanadium and cobalt provides hardness and heat resistance of the steel.

Marking of high speed steels:

The number after the letter "P" indicates the average content of tungsten (as a percentage of the total mass, the letter B is omitted). Then after the letters M, F and K indicate the percentage of molybdenum, vanadium and cobalt.