阅读说明：本技术 钢材及其制备方法、轴承构件、轴承 (Steel material, method for producing same, bearing member, and bearing ) 是由 丁颖 贾刚 井科 王洪昆 王文刚 边志宏 王蒙 王萌 焦杨 马瑞峰 庄权 温博 于 2021-08-11 设计创作，主要内容包括：本发明涉及钢铁材料制备技术领域,具体而言,涉及一种钢材及其制备方法、轴承构件、轴承。钢材的制备方法包括将锻造后的高碳铬轴承钢在300℃～500℃下等温冷却后,空冷,高碳铬轴承钢为GCr15或GCr15SiMn；高温回火后空冷,温度为600℃～700℃,保温时间为3h～6h；淬火加热,温度为(Ac1+20℃)～(Ac1+45℃),保温时间为30min～60min；淬火冷却,温度为170℃～200℃,时间为10min～30min；170℃～200℃回火3h～6h。通过该方法制得的钢材具有高硬度、良好的韧性及抗回火性。本发明还提供了该方法制得的钢材、包括该钢材的轴承构件及轴承。(The invention relates to the technical field of steel material preparation, in particular to a steel material and a preparation method thereof, a bearing component and a bearing. The preparation method of the steel comprises the steps of cooling the forged high-carbon chromium bearing steel at the temperature of 300-500 ℃ at the same temperature, and then cooling the high-carbon chromium bearing steel by air, wherein the high-carbon chromium bearing steel is GCr15 or GCr15 SiMn; air cooling is carried out after high-temperature tempering, the temperature is 600-700 ℃, and the heat preservation time is 3-6 h; quenching and heating at the temperature of between (Ac1+20 ℃) and (Ac1+45 ℃), and keeping the temperature for 30 to 60 minutes; quenching and cooling, wherein the temperature is 170-200 ℃, and the time is 10-30 min; tempering for 3-6 h at 170-200 ℃. The steel prepared by the method has high hardness, good toughness and tempering resistance. The invention also provides the steel prepared by the method, a bearing component comprising the steel and a bearing.)

1. A method for producing a steel material, characterized by comprising the steps of:

s100: cooling the forged high-carbon chromium bearing steel at 300-500 ℃ at the same temperature, and then air-cooling, wherein the high-carbon chromium bearing steel is GCr15 or GCr15 SiMn;

s200: air cooling is carried out after high-temperature tempering, the temperature is 600-700 ℃, and the heat preservation time is 3-6 h;

s300: quenching and heating at the temperature of between (Ac1+20 ℃) and (Ac1+45 ℃), and keeping the temperature for 30 to 60 minutes;

s400: quenching and cooling, wherein the temperature is 170-200 ℃, and the time is 10-30 min;

s500: tempering for 3-6 h at 170-200 ℃.

2. The method of producing a steel product as claimed in claim 1, wherein the high-carbon chromium bearing steel is GCr15, and the temperature of quenching heating is 830 to 835 ℃.

3. The method of producing a steel product as claimed in claim 1, wherein the high-carbon chromium bearing steel is GCr15SiMn, and the temperature of the quenching heating is 810 ℃ to 815 ℃.

4. The method of producing a steel product according to claim 1 wherein the quenching medium for quenching cooling is oil or brine having a mass concentration of 99% to 99.3%.

5. A method of producing a steel product as claimed in claim 4 where the solute in the brine is NaNO₃、NaNO₂、NaCl、KNO₃Or one or more of KCl.

6. The method of producing a steel product as claimed in claim 5 where the solute in the brine is KNO₃And NaNO₃。

7. The method for producing a steel product as claimed in claim 1, wherein the forging is carried out at a temperature of 1080 ℃ to 1180 ℃ for 1 hour to 3 hours.

8. A steel product obtained by the method for producing a steel product according to any one of claims 1 to 7.

9. A bearing component comprising the steel material according to claim 8.

10. A bearing comprising the bearing component of claim 9.

Technical Field

The invention relates to the technical field of steel material preparation, in particular to a steel material and a preparation method thereof, a bearing component and a bearing.

Background

The steel materials from which the bearings are made typically include high carbon chromium bearing steel, medium carbon chromium bearing steel, carburized bearing steel, stainless bearing steel, high temperature bearing steel. Among them, high carbon chromium bearing steel is generally used for manufacturing rolling bearings. Because the rolling bearing has severer working conditions, the rolling bearing has higher requirements on the performance of steel, for example, on the basis of high strength and toughness, the rolling bearing also has high hardness, high strength, tempering resistance and the like.

However, the steel processed by the quenching and tempering heat treatment process adopted in the traditional process for preparing the high-carbon chromium bearing steel has coarse grains and low hardness, and the quenching and heating temperature is high, so that the steel is overheated, the quality of the finally prepared bearing steel is reduced, and the use requirement is difficult to meet.

Disclosure of Invention

Based on this, the present invention provides a method for preparing a steel material having high hardness and fine grains.

In one aspect of the present invention, there is provided a method for producing a steel material, comprising the steps of:

s100: cooling the forged high-carbon chromium bearing steel at 300-500 ℃ at the same temperature, and then air-cooling, wherein the high-carbon chromium bearing steel is GCr15 or GCr15 SiMn;

s200: air cooling is carried out after high-temperature tempering, the temperature is 600-700 ℃, and the heat preservation time is 3-6 h;

s300: quenching and heating at the temperature of between (Ac1+20 ℃) and (Ac1+45 ℃), and keeping the temperature for 30 to 60 minutes;

s400: quenching and cooling, wherein the temperature is 170-200 ℃, and the heat preservation time is 10-30 min;

s500: tempering for 3-6 h at 170-200 ℃.

Optionally, in the above preparation method of the steel, the high-carbon chromium bearing steel is GCr15, and the quenching and heating temperature is 830-835 ℃.

Optionally, in the above preparation method of the steel, the high-carbon chromium bearing steel is GCr15SiMn, and the quenching and heating temperature is 810-815 ℃.

Optionally, in the above method for producing a steel product, the quenching medium for quenching cooling is oil or brine with a mass concentration of 99% to 99.3%.

Optionally, in the above method for preparing steel, the solute in the brine is NaNO₃、NaNO₂、NaCl、KNO₃Or one or more of KCl.

Optionally, in the above method for preparing steel, the solute in the brine is KNO₃And NaNO₃。

Optionally, in the preparation method of the steel, the forging temperature is 1080-1180 ℃, and the forging time is 1-3 hours.

In one aspect of the invention, the steel prepared by the preparation method of the steel is also provided.

In another aspect of the present invention, there is provided a bearing member comprising the steel material described above.

In a further aspect of the invention, there is further provided a bearing comprising a bearing component as described above.

According to the invention, researches show that the initial structure of the steel before quenching is closely related to the structure after quenching, and the size of crystal grains before quenching, the size of carbide and the dispersion degree influence the process of dissolving the carbide into austenite during quenching, thereby playing a role in determining the structure and the size of the crystal grains after quenching. Therefore, the invention optimizes the heat treatment process of the steel, and the steel is tempered at high temperature before quenching and heating, so that the carbide is uniform and fine, and a microstructure beneficial to nucleation is formed. The fine and uniform distribution of the carbide increases the contact area of the carbide and the crystal lattice interface of the ferrite, and after the carbide and the alloy elements are heated and austenitized by heat treatment, the carbide and the alloy elements are more easily dissolved in the ferrite, so that the capacity of the carbide and the alloy elements in the ferrite is improved. So that the precipitation rate and amount of carbides from ferrite are reduced during the formation of martensite by quenching transformation. The formed martensite needles are finer, and the carbon content of martensite is higher, so that the hardness of the obtained high-carbon chromium steel is higher than that of the traditional high-carbon chromium steel. In addition, the introduction of the high-temperature tempering process can also reduce the subsequent quenching heating temperature, and effectively avoids the problem that the crystal grains grow at high temperature to cause the coarse crystal grains of the finally prepared steel. Subsequent low-temperature tempering can reduce quenching stress and improve the dimensional stability of steel. The steel prepared by the invention has high hardness and high grain size on the basis of realizing high strength and toughness.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow chart of a process for producing a steel product according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the invention, one or more examples of which are described below. Each example is provided by way of explanation, not limitation, of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment.

It is therefore intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present invention are disclosed in or are apparent from the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Other than as shown in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients, physical and chemical properties, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". For example, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can be suitably varied by those skilled in the art in seeking to obtain the desired properties utilizing the teachings disclosed herein. The use of numerical ranges by endpoints includes all numbers within that range and any range within that range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, and the like.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise. In the description of the present invention, "a plurality" means at least one, e.g., one, two, etc., unless specifically limited otherwise. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Terms and definitions

Ferrite is a matrix of a pearlite structure, generally refers to an interstitial solid solution in which carbon is dissolved in α -Fe, and has a microstructure of bright polygonal grains similar to that of pure iron, and has a body-centered cubic lattice with small lattice gaps. Ferrite in steel materials generally exists in the form of a plate, a block, a needle, and a network. Ferrite has low strength and hardness, but good plasticity and toughness.

Cementite is a metal compound of iron and carbon. It has complex orthorhombic lattices, usually appear in the structure in crystals of different shapes and sizes, and has a great influence on the mechanical properties of steel. By different heat treatments, cementite can be formed into a sheet, a granule or a discontinuous network, which has very high hardness HBW of 800, very brittle, but almost zero plasticity and toughness.

Pearlite is a structure formed by eutectoid transformation of austenite and simultaneous precipitation of ferrite and cementite lamellae, and belongs to a mechanical mixture formed by ferrite and cementite together. The comprehensive mechanical property is better than that of ferrite and cementite, the mechanical property is between that of ferrite and cementite, namely the strength and hardness are obviously higher than those of ferrite, and the plasticity and toughness are poorer than those of ferrite but better than those of cementite.

Austenite refers to the lamellar microstructure of a steel material, generally consisting of grains. The austenite is in a face-centered cubic structure, and interstitial atoms such as carbon and nitrogen are positioned in the interstitial center of an octahedron of an austenite crystal cell and the center of a face-centered cubic unit cell and the midpoint of an edge. The nucleation site of austenite crystal nucleus is usually on the interface of ferrite and cementite, besides, the boundary of pearlite area and the boundary of ferrite mosaic can be the nucleation site of austenite. The austenite is formed by the steps of higher density of non-uniform nucleation austenite, lower yield strength, good plasticity and easy processing and forming.

Austenitizing refers to a heat treatment process of a metal that heats the steel above a critical point to form austenite, and the heated workpiece is brought to a temperature above the eutectoid temperature to convert ferrite and cementite back to austenite at room temperature.

Bainite (bainite) refers to the transformation that occurs by shear transformation in cooperation with short-range diffusion when austenite is too cold to a temperature between below the pearlite transformation temperature and above the martensite transformation temperature, and the transformation product is bainite. Bainite in steel is generally a mixed structure of ferrite and carbide.

Martensite is a supersaturated solid solution of carbon in α -Fe. The three-dimensional structure morphology of martensite usually has a plate-like or lath-like shape, but in metallographic observation (two-dimensional) usually shows a needle-like shape, and thus it will also be described as a needle-like shape. The crystal structure of martensite is a body-centered tetragonal structure. This structure is generally obtained by accelerated cooling in medium and high carbon steels. The martensite in steel has the obvious characteristics of high hardness and high strength, the lath martensite also has higher toughness and plasticity, and the sheet martensite has poorer toughness.

Ac1 is the temperature at which the steel material starts to form austenite when heated.

In one aspect of the present invention, there is provided a method for producing a steel material, comprising the steps of:

s100: cooling the forged high-carbon chromium bearing steel at 300-500 ℃ at the same temperature, and then air-cooling, wherein the high-carbon chromium bearing steel is GCr15 or GCr15 SiMn;

s200: air cooling is carried out after high-temperature tempering, the temperature is 600-700 ℃, and the heat preservation time is 3-6 h;

s300: quenching and heating at the temperature of between (Ac1+20 ℃) and (Ac1+45 ℃), and keeping the temperature for 30 to 60 minutes;

s400: quenching and cooling, wherein the temperature is 170-200 ℃, and the heat preservation time is 10-30 min;

s500: tempering for 3-6 h at 170-200 ℃.

After isothermal cooling, a bainite structure (carbides are uniformly distributed on ferrite) can be obtained, and the carbides can be finer and uniformly distributed through subsequent high-temperature tempering. The fine and uniform distribution of the carbide increases the contact area of the carbide and the crystal lattice interface of the ferrite, and after the carbide and the alloy elements are heated and austenitized by heat treatment, the carbide and the alloy elements are more easily dissolved in the ferrite, so that the capacity of the carbide and the alloy elements in the ferrite is improved. So that the precipitation rate and amount of carbides from ferrite are reduced during the formation of martensite by quenching transformation. The formed martensite needles are finer, and the carbon content of martensite is higher, so that the hardness of the obtained high-carbon chromium steel is higher than that of the traditional high-carbon chromium steel.

The formed martensite needles are finer, and the martensite has higher carbon content, so that the martensite structure is more stable, and the precipitation of carbides in the martensite is reduced in the tempering process. Therefore, the hardness is not obviously reduced after tempering, so that the finally prepared steel has good tempering resistance. And the temperature of the subsequent quenching and heating process can be reduced after the high-temperature tempering process is added, so that the problem that the tissues of partial areas are overheated and unqualified is avoided, and the reduction of the performance of the final product caused by the growth of crystal grains is also avoided. Subsequent low-temperature tempering can reduce quenching stress and improve the dimensional stability of the high-carbon chromium bearing steel.

In some embodiments, the high carbon chromium bearing steel may be GCr15, wherein the quench heating temperature is from 830 ℃ to 835 ℃.

In some embodiments, the high carbon chromium bearing steel may be GCr15SiMn, wherein the temperature of the quench heating is between 810 ℃ and 815 ℃.

In some embodiments, the quench medium of the quench cooling is an oil or brine with a mass concentration of 99% to 99.3%.

By adopting quenching oil or brine as a quenching medium for quenching and cooling, the high-carbon chromium bearing steel can be rapidly cooled, so that the defects of quenching deformation or cracking and the like of a workpiece are prevented. Workpieces cooled using brine as the quenching medium have better performance than quenching oil cooling.

In some embodiments, the specification of the oil is not limited, and any oil capable of cooling the high-carbon chromium bearing steel may be selected, and may be, for example, common quenching oil, bright quenching oil, rapid quenching oil, high-speed quenching oil, or the like. Preferably, the oil is a rapid quenching oil, and the rapid quenching oil can be deluxe rapid quenching oil.

In some embodiments, the quenching medium is brine with a mass concentration of 99% to 99.3%, and the solute in the brine may be any one of salts commonly used in the art, such as NaNO₃、NaNO₂、NaCl、KNO₃Or one or more of KCl. Preferably, the solute in the brine is KNO₃And NaNO₃And said KNO₃And NaNO₃The mass ratio of (A) to (B) is 1: 1. The ratio of solute to salt affects the viscosity of the quenching medium, which further affects the cooling rate of the medium and the melting point of the salt, and the quenching medium has a better melting point and cooling rate at this ratio, so that the steel can be rapidly cooled.

In some embodiments, the forging is at a temperature of 1080 ℃ to 1180 ℃ for 1 hour to 3 hours.

In one aspect of the invention, the steel prepared by the preparation method of the steel is also provided.

In another aspect of the present invention, there is provided a bearing member comprising the steel material described above.

In some embodiments, the bearing member may be a steel ball, a bearing raceway ring, a rolling element. The bearing raceway ring can be an outer ring or an inner ring. The rolling bodies may be balls, cylindrical rollers, tapered rollers or needle rollers.

In a further aspect of the invention, there is further provided a bearing comprising a bearing component as described above. Here, at least one of the steel balls, the inner ring, the outer ring, and the rolling elements of the bearing is selected from the bearing members described above, and is formed of the predetermined steel material described above.

In some embodiments, the bearing is mainly a rolling bearing, for example, a ball bearing, but rolling bearings other than the above-described rolling bearings, such as a cylindrical roller bearing, a tapered roller bearing, a spherical roller bearing, a needle roller bearing, a thrust cylindrical roller bearing, a thrust tapered roller bearing, a thrust needle roller bearing, a thrust spherical roller bearing, and a self-aligning roller bearing, may be used.

The steel material of the present invention, the production method thereof, the bearing member, and the bearing will be described in further detail below with reference to specific examples and comparative examples.

The following examples, which are not specifically illustrated, employ drugs and equipment, all of which are conventional in the art. The experimental procedures, in which specific conditions are not indicated in the examples, were carried out according to conventional conditions, such as those described in the literature, in books, or as recommended by the manufacturer.

EXAMPLE 1 preparation of GCr15 Steel

Fig. 1 is a preparation process diagram of GCr15 high-carbon chromium steel in the embodiment.

As shown in FIG. 1, GCr15 was heated to 1140 deg.C for forging and heated for 2 h. Then the temperature is reduced to 400 ℃, the GCr15 is cooled for 1 hour isothermally, and then the air is cooled to the room temperature. Then the temperature is increased to 600 ℃ for high-temperature tempering, and the air is cooled to the room temperature after 5 hours.

The GCr15 air-cooled to room temperature was quenched and heated at 830 ℃ for 1 hour. Then placing the mixture in a salt bath at 180 ℃ for salt bath quenching and cooling for 10min, wherein the salt in the salt bath is KNO₃And NaNO₃(mass ratio 1:1), and the mass fraction of water is 0.7%. Then tempering the steel for 5 hours at 180 ℃, and then cooling the steel to room temperature in air. The GCr15 high-carbon chromium steel prepared in the embodiment is subjected to related performance tests, and the test results are shown in Table 1.

EXAMPLE 2 preparation of GCr15 Steel

This example 2 was prepared substantially identically to example 1, except that: the high temperature tempering temperature is different. The method comprises the following specific steps:

GCr15 was forged by heating to 1140 ℃ and holding for 2 h. Then the temperature is reduced to 400 ℃, the GCr15 is cooled for 1 hour isothermally, and then the air is cooled to the room temperature. Then the temperature is raised to 620 ℃ for high-temperature tempering, and the air is cooled to the room temperature after 5 hours.

The GCr15 air-cooled to room temperature was quenched and heated at 830 ℃ for 1 hour. Then placing the mixture in a salt bath at 180 ℃ for salt bath quenching and cooling for 10min, wherein the salt in the salt bath is KNO₃And NaNO₃(mass ratio 1:1), and the mass fraction of water is 0.7%. Then tempering the steel for 5 hours at 180 ℃, and then cooling the steel to room temperature in air. The GCr15 high-carbon chromium steel prepared in the embodiment is subjected to related performance tests, and the test results are shown in Table 1.

EXAMPLE 3 preparation of GCr15 Steel

This example 3 was prepared substantially identically to example 1, except that: the high temperature tempering temperature is different. The method comprises the following specific steps:

GCr15 was forged by heating to 1140 ℃ and holding for 1 h. Then the temperature is reduced to 400 ℃, the GCr15 is cooled for 1 hour isothermally, and then the air is cooled to the room temperature. Then the temperature is raised to 650 ℃ for high-temperature tempering, and the air is cooled to the room temperature after 5 hours.

The GCr15 air-cooled to room temperature was quenched and heated at 830 ℃ for 1 hour. Then placing the mixture in a salt bath at 180 ℃ for salt bath quenching and cooling for 10min, wherein the salt in the salt bath is KNO₃And NaNO₃(mass ratio 1:1), and the mass fraction of water is 0.7%. Then returning at 180 DEG CAfter 5h of fire, air-cooled to room temperature. The GCr15 high-carbon chromium steel prepared in the embodiment is subjected to related performance tests, and the test results are shown in Table 1.

EXAMPLE 4 preparation of GCr15 Steel

This example 4 was prepared substantially identically to example 1, except that: the high temperature tempering temperature is different. The method comprises the following specific steps:

GCr15 was forged by heating to 1140 ℃ and holding for 1 h. Then the temperature is reduced to 400 ℃, the GCr15 is cooled for 1 hour isothermally, and then the air is cooled to the room temperature. Then the temperature is raised to 680 ℃ for high-temperature tempering, and the air is cooled to the room temperature after 5 hours.

The GCr15 air-cooled to room temperature was quenched and heated at 830 ℃ for 1 hour. Then placing the mixture in a salt bath at 180 ℃ for salt bath quenching and cooling for 10min, wherein the salt in the salt bath is KNO₃And NaNO₃(mass ratio 1:1), and the mass fraction of water is 0.7%. Then tempering the steel for 5 hours at 180 ℃, and then cooling the steel to room temperature in air. The GCr15 high-carbon chromium steel prepared in the embodiment is subjected to related performance tests, and the test results are shown in Table 1.

EXAMPLE 5 preparation of GCr15 Steel

This example 5 was prepared substantially identically to example 1, except that: the quenching heating temperature is different. The method comprises the following specific steps:

GCr15 was forged by heating to 1140 ℃ and holding for 1 h. Then the temperature is reduced to 400 ℃, the GCr15 is cooled for 1 hour isothermally, and then the air is cooled to the room temperature. Then the temperature is increased to 600 ℃ for high-temperature tempering, and the air is cooled to the room temperature after 5 hours.

The GCr15 air-cooled to room temperature was quenched and heated at 835 ℃ for 1 hour. Then placing the mixture in a salt bath at 180 ℃ for salt bath quenching and cooling for 10min, wherein the salt in the salt bath is KNO₃And NaNO₃(mass ratio 1:1), and the mass fraction of water is 0.7%. Then tempering the steel for 5 hours at 180 ℃, and then cooling the steel to room temperature in air. The GCr15 high-carbon chromium steel prepared in the embodiment is subjected to related performance tests, and the test results are shown in Table 1.

EXAMPLE 6 preparation of GCr15SiMn Steel

This example 6 was prepared substantially identically to example 1, except that: the steel is GCr15 SiMn. The method comprises the following specific steps:

GCr15SiMn was heated to 1140 ℃ for forging and held for 1 h. Then the temperature is reduced to 400 ℃, GCr15SiMn is cooled for 1h in an isothermal way, and then the air is cooled to the room temperature. Then the temperature is increased to 600 ℃ for high-temperature tempering, and the air is cooled to the room temperature after 5 hours.

The GCr15SiMn air-cooled to room temperature is quenched and heated for 1h at 810 ℃. Then placing the mixture in a salt bath at 180 ℃ for salt bath quenching and cooling for 10min, wherein the salt in the salt bath is KNO₃And NaNO₃(mass ratio 1:1), and the mass fraction of water is 0.7%. Then tempering the steel for 5 hours at 180 ℃, and then cooling the steel to room temperature in air. The GCr15SiMn high-carbon chromium steel prepared in this example was subjected to the relevant performance tests, and the test results are shown in table 1.

Comparative example 1 preparation of GCr15 Steel

Comparative example 1 was prepared substantially the same as example 1, except that: the temperature of the high-temperature tempering is 500 ℃. The method comprises the following specific steps:

GCr15 was forged by heating to 1140 ℃ and holding for 1 h. Then the temperature is reduced to 400 ℃, the GCr15 is cooled for 1 hour isothermally, and then the air is cooled to the room temperature. Then the temperature is increased to 500 ℃ for high-temperature tempering, and the air is cooled to the room temperature after 5 hours.

The GCr15 air-cooled to room temperature was quenched and heated at 835 ℃ for 1 hour. Then placing the mixture in a salt bath at 180 ℃ for salt bath quenching and cooling for 10min, wherein the salt in the salt bath is KNO₃And NaNO₃(mass ratio 1:1), and the mass fraction of water is 0.7%. Then tempering the steel for 5 hours at 180 ℃, and then cooling the steel to room temperature in air. The GCr15 high-carbon chromium steel prepared by the comparative example is subjected to related performance tests, and the test results are shown in Table 1.

Comparative example 2 preparation of GCr15 Steel

Comparative example 2 was prepared substantially the same as example 1, except that: the temperature of quenching heating is 850 ℃. The method comprises the following specific steps:

GCr15 was forged by heating to 1140 ℃ and holding for 1 h. Then the temperature is reduced to 400 ℃, the GCr15 is cooled for 1 hour isothermally, and then the air is cooled to the room temperature. Then the temperature is increased to 600 ℃ for high-temperature tempering, and the air is cooled to the room temperature after 5 hours.

The GCr15 air-cooled to room temperature was quenched and heated at 850 ℃ for 1 hour. Then placing the mixture in a salt bath at 180 ℃ for salt bath quenching and cooling for 10min, wherein the salt in the salt bath is KNO₃And NaNO₃(mass ratio 1:1), and the mass fraction of water is 0.7%. Then tempering the steel for 5 hours at 180 ℃, and then cooling the steel to room temperature in air. The GCr15 high-carbon chromium steel prepared by the comparative example is subjected to related performance tests, and the test results are shown in Table 1.

Comparative example 3 preparation of GCr15 Steel

Comparative example 3 is prepared substantially the same as example 1, except that: high temperature tempering is not performed. The method comprises the following specific steps:

GCr15 was forged by heating to 1140 ℃ and holding for 1 h. Then the temperature is reduced to 400 ℃, the GCr15 is cooled for 1 hour isothermally, and then the air is cooled to the room temperature. Then the temperature is raised to 835 ℃ for quenching and heating for 1 h. Then placing the mixture in a salt bath at 180 ℃ for salt bath quenching and cooling for 7min, wherein the salt in the salt bath is KNO₃And NaNO₃(mass ratio 1:1), and the mass fraction of water is 0.7%. Then tempering the steel for 5 hours at 180 ℃, and then cooling the steel to room temperature in air. The GCr15 high-carbon chromium steel prepared by the comparative example is subjected to related performance tests, and the test results are shown in Table 1.

TABLE 1 results of performance test of steels obtained in examples and comparative examples

According to the test results in the table, the invention leads the grain size and the Rockwell hardness of the steel to be integrally higher by introducing the high-temperature tempering process, adjusting the quenching heating temperature and other process parameters. The grain size of the steel products obtained in examples 1 and 2 can reach grade 10.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.