GOST 19265-73 Rods and strips made of high-speed steel. Specifications

1.2. Deviations in the chemical composition indicated in the table are allowed in the finished product. 2.

table 2

(Changed edition, Amendment No. 3, 4, 6).

Alloy Application

The positive characteristics of this alloy helped to find the use of this steel in household use. Knives are made from it. Moreover, if the product is sharpened correctly, it will be able to cut not only the flesh of an animal, but also a thin metal plate.

Discs made of steel R6M5

The only disadvantage of this product is its sharpening. But, if you know all the tricks of proper sharpening, then this tool will become very useful in everyday life. These products are most often used by hunters and tourists.

Despite the expensive cost, the use of alloy for knives has become very popular in everyday life.

Every man in his house has a power tool, in which drills made of this type of steel are used as auxiliary equipment. The varieties of drills that are made from this R5M6 steel include:

• crown ones, which are used for drywall;
• stepped;
• drills designed for stone, wood or metal.

Not only drills and knives are made from this material. Slotting cutters, hacksaw blades, and countersinks are made from R6M5 steel.

Explanation of the markings of this alloy

The explanation of the R6M5 steel marking is as follows:

• The letter “P” means high-speed or rapid steel, since the marking was based on an abbreviation from the English word “rapid” (read in Russian as rapid), which translated means “fast”. And the number that follows this letter indicates the percentage of tungsten in this alloy. In this case it is equal to 6%, with minor deviations.
• The letter “M” indicates that this alloy contains molybdenum. And the number that follows the letter also shows the amount of its presence in the alloy of this metal as a percentage.

Example of decoding markings

If no additional elements are added to this steel, then its designation ends there. If cobalt is added to the alloy, then it will be designated P6M5K5. Marking "F" - vanadium, "T" - titanium and other additional elements.

According to GOST, R6M5 steel is divided into the following products, which belongs to one of the interstate standards. It describes all the technical requirements related to this brand. Although rolled metal has recently switched to hard alloys, this brand still maintains its leading position in market demand.

https://youtube.com/watch?v=ccSlXrxQTSg

Listed below are some products made from an alloy of these metals and the corresponding GOST for them:

• hot-rolled circles belong to GOST number 2590-88;
• the calibrated rod has GOST 7417-75;
• strips and rods (for the manufacture of these products the steel variety R6M5K5 is used) - GOST 19265-73;
• wheels that have a special finish on the top layer have GOST 14955-77.

Download GOST 2590-88

Download GOST 7417-75

Peculiarities

Steel grades R6M5 and R18 are used not only in the manufacture of knives, but also in the production of taps, drills, and industrial cutting tools. They are distinguished by their ability to maintain hardness and sharpness when exposed to high temperatures and significant shock loads. The high content of carbon and tungsten in the composition gives steel these characteristics.

Heat treatment

To give knives made from P18 and P6M5 increased strength and wear resistance, the metal is subjected to appropriate heat treatment. It takes place in 2 stages:

1. Hardening – heating to a temperature of 1200-1300C. To avoid the formation of cracks, it is carried out gradually. First, the metal is heated to a temperature of 400-500C, then to a temperature of 800-850C. At maximum heating, the workpiece is subjected to heat treatment for a limited time (10-15 seconds for each millimeter of thickness). During hardening, the carbide decomposes, the alloy is saturated with tungsten and carbon.
2. Vacation is carried out at a temperature of 550-560C. It is carried out in 2-3 stages, each lasting at least an hour. At the same time, the strength characteristics of the metal increase.

Steel is heated in special salt baths, which consist of barium chloride (78%) and sodium chloride (22%). Magnesium fluoride is used to deoxidize the solution.

Production of cutting tools

After heat treatment of the steel, the production of cutting tools begins. For this purpose, the workpieces, which are previously checked for compliance with GOST requirements, are sent for grinding. Products made from P18 steel are easier to grind, but they also retain their sharpness for a shorter period of time. Knives made from R6M5 alloy can only be sharpened with professional tools and skills, but their sharpening quality is much better. In production, specialized machines are used for grinding workpieces made of steel R18 and R6M5.

Knife Grif steel P18, birch bark handle.

Use in cutting

Knives made of steel P18 and P6M5 are quick-cutting and universal in use. The metal performs well under heat and mechanical stress. It does not lose strength or deform. Manufacturers of knives made from these steel grades conducted experiments during which they successfully coped not only with slicing various food products (meat, bones, cartilage), but also with cutting wood and even metal plates several millimeters thick!

ACCEPTANCE RULES

4.1. Metal products are accepted in batches.

The batch must consist of metal products from one heat, one group, one size, one subgroup and the same heat treatment regime.

Each batch is accompanied by a quality document in accordance with the requirements of GOST 7566-94.

(Changed edition, Amendment No. 3).

4.2. The surface quality is checked on all bars and strips in the batch.

4.3. To check the chemical composition, one sample is taken from the melt, from a batch of rods or strips - one rod or strip.

4.4. To check the sizes - 10% of rods, strips from the batch, but not less than five pieces.

4.5. To control the hardness of annealed steel:

for metal products with a diameter or thickness of up to 30 mm, two rods or two strips from 1 ton are selected, but not less than eight rods or strips per batch; for metal products with a diameter or thickness over 30 mm - 15% of rods from the lot, but not less than five pieces, or two strips from 1 ton, but not less than five strips from the lot.

4.3 — 4.5. (Changed edition, Amendment No. 3).

4.6. To check the macrostructure - two rods, two blanks or strips from a batch.

4.7. (Deleted, Amendment No. 6).

4.8. To check carbide heterogeneity, two rods and two strips from the batch are selected.

4.9. To check the depth of the decarburized layer - two rods or two strips from the batch. Rods with a diameter and thickness of more than 100 mm may not be controlled for decarburization.

4.10. To check the hardness after quenching and tempering and the grain size of austenite - one rod or one strip from a batch, but not less than two from a heat.

4.9 — 4.10. (Changed edition, Amendment No. 3).

4.11. If unsatisfactory test results are obtained for at least one of the indicators, a test is carried out in accordance with GOST 7566-94.

4.12. Carbide heterogeneity, macrostructure and hardness after quenching and tempering of rods with a diameter or thickness of up to 40 mm inclusive are ensured by manufacturing technology.

(Changed edition, Amendment No. 1, 6).

4.13. (Deleted, Amendment No. 3).

Application of high speed steels

Cobalt and vanadium high-speed steels are used for processing structural steels at high cutting conditions, as well as heat-resistant, stainless and high-strength steels.

Tools made from cobalt steels are used for machining heat-resistant and corrosion-resistant steels, as well as other difficult-to-cut alloys, and are suitable for use in conditions of insufficient cooling, interrupted cutting and vibration. The area of ​​application of high-speed vanadium steels is the manufacture of tools intended for finishing of hard-to-cut metals (reamers, broaches, etc.)

High speed steel P18

The alloy contains 18% tungsten and is relatively easy to grind. The hardness of the tool after heat treatment is HRC 62-65, red hardness 600ºС. The presence of an excess carbide phase gives the steel a fine-grained structure, increases the wear resistance of products, and reduces sensitivity to overheating. Quick cutter P18 is used for the manufacture of cutters, shaver, drills, cutters, taps, reamers. The main disadvantage of tungsten steels is significant carbide heterogeneity, which becomes critical in products with large cross-sections. Carbide heterogeneity reduces tool life and leads to chipping of cutting edges.

High-speed steel R6M5

High-speed steels with a high tungsten content have recently been replaced by complex alloys in which tungsten is partially replaced by molybdenum. In this way, the carbide heterogeneity of the metal is noticeably reduced, which increases the strength of the tool and its resistance to impact loads. Among the typical representatives of the group of tungsten-molybdenum steels are R6M5 and R6M3 steels.

The technological qualities of R6M5 steel are close to those of R18 steel, that is, these alloys are interchangeable. In some cases, the use of R5M6 steel is more preferable, in particular, in the manufacture of large-sized tools. Due to its high strength, manufacturability and durability, R6M5 steel is currently the most popular of the high-productivity steels.

The range of high-speed steel includes:

• Circle;
• Square:
• Sheet;
• Band.

High-speed steel wheels are used for the manufacture of drills, drills, saws, taps and other cutting tools. Squares are used less frequently, mainly for the production of turning tools and knives for electric planers.

Steel hardening

The heat treatment of R6M5 has a number of features associated with the properties of this brand regarding decarburization and the duration of heating for hardening. First, they take a vacation at 200 and 300 degrees for an hour each. Then 3 minutes of processing at 690 and 860 degrees, and then a minute and a half of processing at a temperature of 1230 degrees. After which the metal is cooled to a nonequilibrium state in saltpeter, oil and air.

Subsequently, triple tempering is used at 560 degrees with an hour and a half exposure. At these stages, alloying elements are added to form carbide to create sufficient strength. It is also necessary to carry out preliminary annealing, which eliminates the brittleness of the metal and gives additional strength.

Characteristics and grades of HSS steel

High-speed varieties are high-carbon steels. Some brands contain a fairly large amount of tungsten. In addition, they may contain cobalt and molybdenum. If we talk about the hardness of alloys, the indicator is most often in the range of 62–64 units of the HRC scale. Comparing products made from high-speed steel and carbide, it is worth noting that the first option is distinguished by a fairly affordable price and increased wear resistance.

Recently, it has been customary to distinguish 3 main groups of HSS steel, each of which has its own characteristics:

1. High tungsten content (T)
2. High Molybdenum (M)
3. High alloy

Tungsten steels

Not the most popular variety. This is due to the fact that tungsten is quite rare and expensive. The most common grades of tungsten steel are T1 and T15. The second contains cobalt and vanadium, therefore they are suitable for the production of accessories that have increased requirements for strength and resistance to high temperatures.

Chemical composition of tungsten HSS steels

Molybdenum and high alloy steels

They are very widespread. May contain cobalt and tungsten. Those brands whose formula includes carbon and vanadium are characterized by increased strength and wear resistance, and resistance to abrasives. Alloys, starting with M41, are used to produce devices that retain their characteristics even when super heated. To create equipment designed for work at low temperatures, steels with molybdenum are also used, but they are subject to additional processing.

Chemical composition of molybdenum HSS steels

Chemical composition of high alloy HSS steels

When selecting products made from molybdenum material, it is worth considering the features of a particular brand:

1. M1. Ideal for releasing drills. They are flexible and shock resistant. But they cannot boast of significant red fastness.
2. M2. One of the most popular materials. Often used for the production of tools for various purposes. The product is suitable for intensive work using machines. The main feature of such a tool is its exceptional red resistance, which means the cutting element will retain its qualities for a long time. Our catalog presents drills of the HSS-STANDARD series made of this alloy
3. M7. Ideal for producing large drills designed for drilling materials of increased hardness or thick sheets.
4. M35. It has increased red fastness due to the increased amount of cobalt in the formula. But it has low resistance to shock loads.
5. M42. Contains a large amount of cobalt, therefore it has excellent red fastness. In addition, it is extremely resistant to abrasion. Ideal for making accessories for working with particularly hard or even viscous materials. Core cutters made from this material are presented in the HSS-CO 8 line of drills
6. M50. Often used to produce drills that come with portable equipment.

TEST METHODS

5.1. Selection and preparation of samples to determine the chemical composition of steel should be carried out in accordance with GOST 7565-81, chemical analysis - in accordance with GOST 12344-88, GOST 12345-2001, GOST 12346-78, GOST 12347-77 GOST 12348-78, GOST 12349-83, GOST 12350-78, GOST 12351-81, GOST 12352-81, GOST 12353-78, GOST 12354-81, GOST 12355-78, GOST 12359-99, GOST 12361-82, GOST 28473-90 or other methods that provide the necessary accuracy.

(Changed edition, Rev., No. 1, 4, 5, 6).

5.2. The dimensions of hot-rolled and forged steel are checked with measuring tools and templates, while calibrated steel and steel with special surface finishes are checked with micrometers or staples.

(Changed edition, Rev., No. 2).

5.3. The hardness of the finished annealed steel is checked according to GOST 9012-59 after stripping the decarburized layer.

The test is carried out at one end of the bar or strip at a distance of approximately 100 mm from the end.

The number of prints must be at least three. Each hardness value must correspond to that indicated in the table. 3.

5.4. Hardness after quenching and tempering is determined according to GOST 9013-59 on samples taken from the finished profile. The control is carried out on a plane perpendicular to the direction of drawing. The number of prints on each sample must be at least three.

The heating temperature for quenching and tempering of samples must correspond to the values ​​​​indicated in table. 3.

Cooling of samples after quenching is carried out in oil.

The samples are released two or three times, with holding time for 1 hour and cooling in air.

The holding time during heating is set according to Fig. 1.

1
-
for rectangular samples;
2
- for round samples

Crap. 1

The cutting pattern, shape and dimensions of the samples are shown in Table. 6a.

Table 6a

mm

5.3, 5.4. (Changed edition, Rev., No. 3).

5.5. The quality of the steel surface is checked without the use of magnifying devices. If necessary, the surface is pre-cleaned with rings or a snake.

5.6. To carry out tests according to paragraphs. 4.5 - 4.10 one template (sample) is cut from each selected unit of product.

One sample can be used for various types of tests.

5.7. The macrostructure of rods and strips is checked without the use of magnifying devices in accordance with GOST 10243-75 by etching templates taken from the finished metal or from an intermediate workpiece.

Point-spot heterogeneity is assessed using the scale given in Appendix 2a.

5.6, 5.7. (Changed edition, Amendment No. 3).

5.8. The type of fracture is checked by external inspection without the use of magnifying devices.

To control fracture, samples cut from the finished annealed metal are subjected to quenching.

5.9. The assessment of carbide heterogeneity of rods and strips is carried out on samples cut at a distance of at least 30 mm from the end crush zone according to Table. 6a on a plane parallel to the drawing direction, and for angular carbides on a plane perpendicular to the drawing direction.

Cutting samples for thin sections is carried out in ways that prevent crushing and bending of fibers in the controlled part of the sample.

Samples in the form of sectors are subjected to hardening according to the regime indicated in the table. 3 for the tested steel grade, tempering for at least 1 hour at 680 - 700 °C after heating and subsequent etching in a 4% solution of nitric acid in ethyl alcohol.

It is possible to control carbide heterogeneity on samples after quenching at a temperature of 900 °C without tempering, followed by etching in a 10% solution of nitric acid in ethyl alcohol.

Carbide heterogeneity depending on the cross-sectional shape of the steel should be controlled in accordance with Table. 7.

Table 7

Carbide heterogeneity is assessed at magnification (90 - 100). Accumulations of “angular” carbides in steel with a special surface finish are assessed at magnification (400 - 500).

The carbide heterogeneity score is determined by comparison with the standards of scale No. 1 - for steel grades R18, R12F3, R18K5F2, R9M4K8 and scale No. 2 - for steel grades R6M5, R6M5F3, 11R3AM3F2, R9K5, R6M5K5, R2AM9K5 and according to Appendix 1.

The carbide heterogeneity score of each section is set as the arithmetic mean of the scores of the five worst fields of view.

Note. If, when receiving a fractional score, the number after the decimal point is less than or equal to 5, rounding should be done towards a lower point, if more than 5 - towards a higher point.

(Changed edition, Amendment No. 2, 3, 4, 5, 6).

5.10. (Deleted, Amendment No. 2).

5.11. The depth of the decarbonized layer is determined according to GOST 1763-68. In case of disagreement in quality assessment, the M2 method should be used.

The depth of the decarburized layer of the steel strip must be measured along the wide side of the strip.

(Changed edition, Amendment No. 6).

5.12. (Deleted, Amendment No. 3).

5.13. The grain size of austenite is determined according to GOST 5639-82 by the Snyder-Graff method or by comparison with standards on a scale on hardened samples cut according to table. 6a so that the control location corresponds to table. 7. If disagreements arise, the Snyder-Graff method is used.

Inspection is carried out on a polished section plane perpendicular to the drawing direction.

The samples are subjected to hardening at the temperatures indicated in the table. 3. The holding time during heating is set according to Fig. 1 given in clause 5.4.

(Changed edition, Amendment No. 6).

5.14. It is allowed to use statistical and non-destructive testing methods.

If disagreements arise, control methods regulated by this standard are used.

(Introduced
additionally, Amendment No. 3 ).

Manufacturing and processing of high-speed steels

High-speed steels are produced both by the classical method (casting steel into ingots, rolling and forging) and by powder metallurgy methods (spraying a jet of liquid steel with nitrogen). The quality of high-speed steel is largely determined by the degree of its forging. When insufficient forging of steel produced by the classical method, carbide segregation is observed.

A common mistake when making high-speed steels is to treat them as “self-hardening steels.” That is, it is enough to heat the steel and cool it in air, and you can get a hard, wear-resistant material. This approach absolutely does not take into account the features of high-alloy tool steels.

Before hardening, high-speed steels must be annealed. In poorly annealed steels, a special type of defect is observed: naphthalene fracture, when, despite the normal hardness of the steel, it has increased brittleness.

A competent choice of quenching temperature ensures maximum solubility of alloying additives in α-iron, but does not lead to grain growth.

After quenching, 25–30% retained austenite remains in the steel. In addition to reducing the hardness of the tool, retained austenite leads to a decrease in the thermal conductivity of steel, which is extremely undesirable for working conditions with intense heating of the cutting edge. Reducing the amount of retained austenite is achieved in two ways: by cold treating the steel or by repeated tempering. When processing steel by cold, it is cooled to −80…−70 °C, then tempered. When tempering multiple times, the “heating-holding-cooling” cycle is carried out 2-3 times. In both cases, a significant reduction in the amount of retained austenite is achieved, but it is not possible to completely get rid of it.

Principles of alloying high-speed steels

The high hardness of martensite is explained by the dissolution of carbon in α-iron. It is known that when tempering from martensite in carbon steel, tiny particles of carbide are released. While the released carbides are still in the finest dispersed dispersion (that is, at the first stage of precipitation when tempered to 200 °C), the hardness does not noticeably decrease. But if the tempering temperature is raised above 200 °C, carbide precipitation increases and the hardness decreases.

In order for steel to consistently maintain its hardness when heated, it must be alloyed with elements that would complicate the process of coagulation of carbides. If you introduce some carbide-forming element into steel in such an amount that it forms a special carbide, then the red-hardness increases abruptly. This is due to the fact that the special carbide precipitates from martensite and coagulates at higher temperatures than iron carbide, since this requires not only the diffusion of carbon, but also the diffusion of alloying elements. Almost noticeable coagulation of special carbides of chromium, tungsten, molybdenum, vanadium occurs at temperatures above 500 °C.

Red resistance is created by alloying steel with carbide-forming elements (tungsten, molybdenum, chromium, vanadium) in such an amount that they bind almost all the carbon into special carbides, and these carbides go into solution during quenching. Despite the strong difference in the general chemical composition, the composition of the solid solution is very similar in all steels, the atomic sum W + Mo + V, which determines the red resistance, is approximately 4% (atomic), hence the red resistance and cutting properties of different grades of high-speed steels are similar. High-speed steel containing cobalt has superior cutting properties to other steels (it increases red-hardness), but cobalt is a very expensive element.

Features of heat treatment of R6M5

Hardening of workpieces based on R6M5 is a complex and labor-intensive process. Specialists use a stepwise heat treatment model with long-term temperature maintenance within specified ranges.

Work is performed in a certain sequence.

• Vacation within 200 degrees for an hour.
• Repeated tempering when the temperature rises to 300 degrees. As in the first case, the duration of the procedure is one hour.
• Heating the workpiece to 690 degrees while maintaining the set temperature for 3 minutes.
• Raising the temperature to 860 degrees and holding for the same 3 minutes.
• Heating to the hardening temperature - 1230 degrees, holding for about 1.5 minutes and subsequent sharp cooling. Oil or saltpeter is used as a cooling compound. If these materials are not available, air cooling is allowed.
• Three times tempering at 560 degrees. The duration of each stage is 1.5 hours.

During tempering, alloying additives are added to the alloy. They provoke the formation of carbides, which increase the strength characteristics of the product.

Hardening

Nitriding is allowed, which increases the corrosion resistance of the metal, its hardness and wear resistance. The procedure takes place in a gas chamber. The alloy is heated to a predetermined temperature, after which it is exposed to nitrogen and ammonia. The duration of the procedure is 40 minutes.

Certain products made from R6M5 steel are galvanized. The operation takes place in a gas or liquid environment containing a large amount of Zn and takes about 30 minutes. Upon completion, the workpiece acquires a reliable protective coating.

Hot galvanizing of workpieces

Sharp knife made from quick cutter R6M5

Attention!!!

This homemade product is posted for informational purposes only. The creation and use as a bladed weapon is prohibited; according to Article 223.4 of the Criminal Code of the Russian Federation, it is punishable by imprisonment for up to two years!

This steel is quite durable, it is enough for long-term heavy work. This steel does not lose its strength even at high temperature loads. The only drawback of this metal is that it is very difficult to harden it with your own hands. Hardening requires repeated heating, tempering, and special chemicals, such as saltpeter, for cooling. But if you process the metal carefully, without overheating, then you won’t need to harden it. So, let's look in more detail at how to make a knife from R6M5 steel.

Materials and tools used by the author:

List of materials:

— R6M5 steel (hacksaw blade); - a piece of wood for the handle; - epoxy adhesive; - a piece of brass for the handle; - oil or varnish to impregnate the handle.

List of tools:

- Bulgarian; - vice; - grinder; — orbital sander or machine; - drill; — a clamp (the author’s homemade one is made from wood); - marker; - sandpaper; - jigsaw.

Knife making process:

Step one. Cutting out the main profile

First we need to figure out what our knife will look like. Draw the profile of the knife on the workpiece using a marker. Well, then you can start cutting. We cut the workpiece using a grinder, but when cutting P6M5 there is one nuance. This steel is quite brittle and breaks when subjected to strong bending. All we need to do is make small cuts with a grinder in the areas that we need to remove. Well, then we break them off with pliers, like glass.

Step two.
Finalizing the profile Step three.
Bevels and sanding The final finishing is done by hand using fine sandpaper soaked in water. Well, at the very end, the blade can be polished on a machine using GOI paste or another paste.

Step four. Brass insert

There is a brass insert at the front of the handle. We select the desired piece of brass and drill a series of holes in it. Then these holes are bored out with a flat file so that the shank of the blade can fit in. At the same step, you can immediately give the workpiece an oval shape on the sharpener. The author immediately polished the part on the machine, since this would be much more difficult to do later.

Step five. Blank for handle

Step six. Final modification of the knife

When the glue dries, we take out our knife and draw the desired handle profile with a pencil. Next, we cut off the excess with a jigsaw; the fastest way to do this is with a jigsaw. We grind the handle to obtain the desired profile, rough processing can be done on a sharpening machine or grinder. Well, we carry out finer processing manually using sandpaper. Making the handle absolutely smooth.

I hope you liked the project and found useful information for yourself. Good luck and creative inspiration if you want to repeat the homemade product. Don't forget to share your ideas and developments with us.

Attention!!!

This homemade product is posted for informational purposes only. The creation and use as a bladed weapon is prohibited; according to Article 223.4 of the Criminal Code of the Russian Federation, it is punishable by imprisonment for up to two years!

Source

Become the author of the site, publish your own articles, descriptions of homemade products and pay for the text. Read more here.

Characteristics of high-speed steels

Hot hardness

At normal temperatures, the hardness of carbon steel is even slightly higher than the hardness of high-speed steel. However, during operation of the cutting tool, intense heat is generated. In this case, up to 80% of the released heat is spent on heating the instrument. Due to an increase in the temperature of the cutting edge, the tool material begins to temper and its hardness decreases.

After heating to 200 °C, the hardness of carbon steel begins to rapidly decrease. For this steel, a cutting mode in which the tool would heat up above 200 °C is unacceptable. High-speed steel retains its high hardness when heated to 500–600 °C. High speed steel tools are more productive than carbon steel tools.

Red fastness

If hot hardness characterizes what temperature steel can withstand, then red hardness characterizes how long the steel will withstand such a temperature. That is, how long will quenched and tempered steel resist softening when heated.

There are several characteristics of red fastness. Let's give two of them.

The first characteristic shows what hardness the steel will have after tempering at a certain temperature for a given time.

The second way to characterize red hardness is based on the fact that the intensity of the decrease in hot hardness can be measured not only at high temperature, but also at room temperature, since the hardness decrease curves at high temperature and room temperature are equidistant, and measuring hardness at room temperature, of course, is much easier than at high. Experiments have shown that cutting properties are lost at a hardness of 50 HRC at cutting temperature, which corresponds to approximately 58 HRC at room temperature. Hence, red hardness is characterized by a tempering temperature at which in 4 hours the hardness decreases to 58 HRC (designation K4р58). Characteristics of heat resistance of carbon and red resistance of high-speed tool steels

Fracture Resistance

In addition to “hot” properties, high mechanical properties are also required from the cutting tool material; This means resistance to brittle fracture, since at high hardness (more than 60 HRC) fracture always occurs by a brittle mechanism. The strength of such high-hard materials is usually defined as the resistance to fracture during bending of prismatic, uncut specimens under static (slow) and dynamic (fast) loading. The higher the strength, the greater the force the working part of the tool can withstand, the greater the feed and depth of cut that can be applied, and this increases the productivity of the cutting process.

Chemical composition of high-speed steels

Chemical composition of some high-speed steels

TECHNICAL REQUIREMENTS

3.1a. Rods and strips are manufactured in accordance with the requirements of this standard according to technological regulations approved in the prescribed manner.

(Introduced
additionally, Amendment No. 3 ).
3.1. The hardness of steel in the annealed state, the hardness of samples after quenching and tempering, the temperature of quenching and tempering must correspond to the values ​​​​indicated in table. 3.

Table 3

Notes:

1. Permissible deviations from the given temperatures should not exceed ± 10 °C.

2. Hardness values ​​after quenching and tempering depending on the tempering temperature are given in Appendix 4.

At the request of the consumer, steel grades R12F3, R9K5, R6M5F3, R6M5K5 are manufactured with a hardness not exceeding 255 HB (indentation diameter is not less than 3.8 mm), steel grades R18K5F2, R9M4K8 - with a hardness not exceeding 269 HB (indentation diameter is not less than 3 .7 mm).

(Changed edition, Amendment No. 3, 4, 5, 6).

3.2. The following are not allowed in the macrostructure of steel: shrinkage looseness, delamination, bubbles, inclusions and cracks.

Defects of the macrostructure are allowed, not exceeding the values ​​​​indicated in the table. 3a.

Table 3a

Group I standards are achieved by electroslag remelting.

(Changed edition, Amendment No. 3, 4).

3.3. (Deleted, Rev. No. 2).

3.4. (Deleted, Amendment No. 6).

3.5. Carbide heterogeneity should not exceed the values ​​given in table. 4.

Table 4

The carbide heterogeneity of the strip must correspond to the carbide heterogeneity of a square profile with an equal cross-sectional area.

In rods with special surface finishing of grades R6M5, R6M5F3, 11R3AM3F2, R9K5, R6M5K5, R2AM9K5, accumulations of “angular” carbides are not allowed. Single “angular” carbides occurring in individual fields of view are allowed.

Group I standards are achieved by electroslag remelting.

(Changed edition, Amendment No. 3, 4, 6).

3.5a, 3.5b (Excluded, Amendment No. 3).

3.6. (Deleted, Amendment No. 2).

3.7. The depth of the decarburized layer of hot-rolled, forged and calibrated steels should not exceed on one side:

0.3 mm plus 2% of the diameter or thickness - for diameters or thicknesses up to 20 mm;

0.5 mm plus 1% of diameter or thickness - for diameters or thicknesses over 20 mm.

On bars with special surface finishing, the decarburized layer is not allowed.

3.8. The ends of the rods and strips must be evenly cut or chopped off, without burrs or chips.

The length of the crumpled ends should not exceed:

1.5 diameter or thickness - for metal products with a diameter or thickness of up to 10 mm;

40 mm - for metal products with a diameter or thickness over 10 to 60 mm;

60 mm - for metal products with a diameter or thickness over 60 mm.

3.7, 3.8. (Changed edition, Amendment No. 3).

3.9. On the surface of rods and strips of subgroup a

There should be no rolled or unrolled bubbles, contamination, stress and grinding cracks, sunsets and forks, rolling captivity. Defects must be removed by shallow cutting or grinding, the depth of which should not exceed the size tolerance. Individual small scratches, ripples, prints and other defects of mechanical origin with a depth not exceeding half the size tolerance are allowed without cleaning.

On the surface of rods and strips of subgroup b

Defects are allowed if their depth, determined by the control filing, does not exceed the standards given in clause 3.7 (depth of the decarbonized layer).

(Changed edition, Amendment No. 3, 4).

3.10. The surface of calibrated steel must meet the requirements of GOST 1051-73, steel with special surface finishing - groups B, D, D GOST 14955-77.

The surface finish group must be specified when ordering.

3.11. By agreement of the parties, hot-rolled and forged steel of round section is manufactured with a rough-ground or turned surface.

On the surface of rough-ground or turned rods, defects and decarburization are allowed, not exceeding 25% of the standards specified in clause 3.7.

3.12. (Excluded, Amendment, No. 2),

3.13, 3.14. (Excluded, Amendment No. 3).

3.15. The grain size of the austenite steel after hardening should correspond to that indicated in the table. 5.

Table 5

(Introduced
additionally, Amendment No. 3 ).

Types of HSS steels

HSS steels come in three categories:

• tungsten (T1-T15);
• molybdenum (M1-M36);
• highly alloyed (M41-M62).

The most commonly used grade is T1 and the alloy with the addition of cobalt and vanadium T15. T15 steel is used to produce tools that are needed to work at high temperatures and increased wear.

Tungsten steels

Not the most popular variety. This is due to the fact that tungsten is quite rare and expensive. The most common grades of tungsten steel are T1 and T15. The second contains cobalt and vanadium, therefore they are suitable for the production of accessories that have increased requirements for strength and resistance to high temperatures.

Molybdenum HSS drills

The main alloying component of steels in this group is molybdenum. Also in different quantities may contain:

1. tungsten,
2. cobalt;
3. vanadium;
4. carbon;
5. and other components.

The most widely used are HSS drills made from the following types of molybdenum high-speed steels.

1. M1. General purpose tools are produced from this grade of steel (8% molybdenum). These HSS drills are highly flexible and resistant to impact loads. Red fastness is lower than that of analogues.
2. M2 (domestic equivalent - P6M5). This is the most common material for the production of HSS drills. The alloy contains 6% tungsten and 5% molybdenum. It has balanced strength, hardness and heat resistance.
3. M3 (domestic equivalent - R6M5F3). This alloy also contains 3% vanadium. HSS drills made from this steel have lower abrasive wear.
4. M7. The main alloying components are molybdenum (8.75%), vanadium (2%) and tungsten (1.75%). Drills made from this HSS steel are used for drilling hard and thick sheet metals.
5. M35 (domestic equivalent - R6M5K5). In addition to tungsten, molybdenum and vanadium, this alloy contains cobalt (5%), as well as small amounts of manganese, silicon and nickel. The advantages of this material are good toughness, excellent grindability, heat and wear resistance. HSS drills made from this alloy are used when processing workpieces made of improved alloy and stainless steels under conditions of increased heating of the cutting edge.

High alloy HSS drills

To produce high-alloy HSS drills (having high impact strength and operating in cold conditions), molybdenum group alloys are used, which are subjected to special heat treatment.

1. M47 (domestic analogue - R2AM9K5). Contains large quantities of molybdenum (9%) and cobalt (4.7–5.2%). The alloy has an increased tendency to decarburization and overheating during quenching. Sandability is low. HSS drills made from this alloy are used for machining workpieces made of improved alloy and stainless steels.
2. M42. Contains a large amount of cobalt and molybdenum (8 and 9.5%, respectively). HSS drills made from this alloy are characterized by increased red hardness and abrasion resistance. Such tools are used when processing viscous and complex metals.

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Main characteristics of the alloy

High-speed steel R6M5 belongs to the alloy category. It has high strength characteristics, is resistant to corrosion, sudden heating and cooling.

The P6M5-based tool works great at high speed and is capable of interacting with wood, metal, plastic and other materials.

Chemical composition of R6M5 steel:

• iron – about 80%;
• carbon – from 0.85 to 0.9%;
• silicon – up to 0.5%;
• manganese – up to 0.5%;
• nickel – up to 0.4%;
• sulfur – up to 0.025%;
• phosphorus – up to 0.03%;
• chromium – from 3.8 to 4.4%;
• molybdenum – from 4.8 to 5.3%;
• tungsten – from 5.5 to 6.5%;
• vanadium – from 1.7 to 2.1%;
• cobalt – up to 0.5%.

A rich set of alloying elements, as well as low sulfur and phosphorus content, provided the R6M5 metal with excellent performance characteristics.

• The alloy does not lose mechanical strength when heated. Products based on it resist incandescence and retain their characteristics during long-term operation at high speed.
• Cutting tools based on P6M5 hold an edge well and require minimal maintenance.
• Steel has high impact strength, which increases its resistance to external mechanical stress.
• P6M5 can be processed with cutting and grinding tools.

Products made from the R6M5 alloy work well with acid-resistant and heat-resistant steels belonging to the austenitic class.

The alloy also has disadvantages, albeit in small quantities:

• the difficulty of manual processing of products from R6M5;
• reduction in sharpening quality during sudden cooling;
• thin edge on a cutting tool.

The listed disadvantages are not critical and have a minimal impact on the ease of use of the tool.

Where are high speed steels used?

The scope of wear-resistant metal depends on the composition that determines its working properties. Basically, this is a tool that has high demands on strength, heat resistance, and long service life.

• Production of drills, cutters, cutters, taps;
• Manufacturing cutting edges for tools, which in some cases can be removable;
• Parts for metalworking machines and equipment;
• Manufacturing of tools used for finishing hard-to-cut metal products.

Experts give the following recommendations on the use of these metal grades:

• Tungsten-molybdenum compounds are suitable for tools intended for roughing products, manufacturing cutters, broaches and shaver.
• Cobalt compounds are used for processing heat-resistant and corrosion-resistant products in difficult conditions.
• Vanadium alloys are used for finishing materials.
• The P9 grade is used to create equipment elements that are not subject to excessive load.
• Grade P18 is suitable for tools with complex shapes and shaped products with increased wear resistance requirements.

The range of metal products is represented by square, circle, strip, and sheet metal. Most often, cutting tools are made from a circle. Square steel is used for the production of electric planers, knives, and turning tools. If you have doubts about the correct choice of a suitable alloy, it is better to contact specialists. Specialized companies will be able to select high-quality rental products with the required performance characteristics.

Sharpening of steel products R6M5

Tools made from P6M5 lose their properties as a result of intensive use. Abrasive wheels help restore the sharpness of the cutting edge. Operating at high speeds, they evenly remove metal, providing high-quality and fast sharpening.

Experts recommend sharpening products in two stages.

1. Pre-treatment with a wheel using grade 40 grit.
2. Finish sharpening with circles with grit grade 25 – 16.

Two-stage exposure guarantees uniform surface treatment, as well as complete restoration of the cutting ability of the tool.

Drill sharpening

Decoding - what the marking symbols mean

Elements of equipment and devices have a high strength index, the material has excellent viscosity. Steel ensures long-term performance, both in product components and in blades or finished tools.

Such markings are a legacy of the Soviet era:

1. The letter “P” is an indicator of high-speed steels. The expression comes from the translation of the English “rapid” - “swift”.
2. The sign after “P” indicates the presence of tungsten in the composition as a percentage. For this particular metal it is in the range of 6% with minor deviations.
3. This is followed by the letter “M”, indicating the presence of molybdenum in the stamp. The next indicator is the percentage of presence of the element in the total mass.
4. In addition to M, high-speed steels can include the following designations in their markings: “K” - cobalt, “T” - titanium, “F” - vanadium, “C” - zirconium.

Considering the designation “P6M5”, decoding can also include other letters. If the steel was smelted by electroslag remelting, an addition appears in the form of “Ш” (Р6М5-Ш). With the introduction of the latest technologies into the production process, the following wording now appears - P6AM5. This means adding nitrogen to the overall composition.