阅读说明：本技术 一种含稀土元素的高碳铬轴承钢及制备方法 (High-carbon chromium bearing steel containing rare earth elements and preparation method thereof ) 是由 耿鑫 李晓凯 李花兵 刘福斌 王磊英 苗红生 赵海东 于 2020-12-08 设计创作，主要内容包括：本发明涉及一种含稀土元素的高碳铬轴承钢,按重量百分比计,由以下组分组成：C：0.95-1.05％；Cr：1.4-1.65％；Si：0.45-0.75％；Mn：0.95-1.25％；Ce：0.015-0.05％；Mo：≤0.10％；Ni≤0.30％；Cu≤0.25％；P≤0.025％；S：≤0.005％；O：≤0.001％；Al：≤0.05％；Ti≤0.003％；余量为Fe和不可避免的杂质。本发明通过对轴承钢合金成分的优化、结合制备工艺的改进,得到技术效果为：轴承钢材料具备低的氧、硫含量,且实验证明,相较于现有GCr15SiMn轴承钢,本发明的改进型GCr15SiMn轴承钢的纯净度和力学性能均得到明显提高,轴承钢的冲击性能提高最优可达70％以上,抗拉强度提高最优可达20％以上,硬度提高最优可达7％以上。(The invention relates to high-carbon chromium bearing steel containing rare earth elements, which comprises the following components in percentage by weight: c: 0.95-1.05%; cr: 1.4-1.65%; si: 0.45 to 0.75 percent; mn: 0.95-1.25%; ce: 0.015-0.05%; mo: less than or equal to 0.10 percent; ni is less than or equal to 0.30 percent; cu is less than or equal to 0.25 percent; p is less than or equal to 0.025 percent; s: less than or equal to 0.005 percent; o: less than or equal to 0.001 percent; al: less than or equal to 0.05 percent; ti is less than or equal to 0.003 percent; the balance being Fe and unavoidable impurities. The invention optimizes the alloy components of the bearing steel and combines the improvement of the preparation process to obtain the technical effects that: the bearing steel material has low oxygen and sulfur contents, and experiments prove that compared with the existing GCr15SiMn bearing steel, the improved GCr15SiMn bearing steel provided by the invention has the advantages that the purity and the mechanical property are obviously improved, the impact property of the bearing steel is optimally improved by more than 70%, the tensile strength is optimally improved by more than 20%, and the hardness is optimally improved by more than 7%.)

1. The high-carbon chromium bearing steel containing rare earth elements is characterized by comprising the following components in percentage by weight: c: 0.95-1.05%; cr: 1.4-1.65%; si: 0.45 to 0.75 percent; mn: 0.95-1.25%; ce: 0.015-0.05%; mo: less than or equal to 0.10 percent; ni is less than or equal to 0.30 percent; cu is less than or equal to 0.25 percent; p is less than or equal to 0.025 percent; s: less than or equal to 0.005 percent; o: less than or equal to 0.001 percent; al: less than or equal to 0.05 percent; ti is less than or equal to 0.003 percent; the balance being Fe and unavoidable impurities.

2. The rare earth element-containing high carbon chromium bearing steel as claimed in claim 1, wherein the content of Ce is 0.016 to 0.020%.

3. A preparation method of high-carbon chromium bearing steel containing rare earth elements is characterized by comprising the following steps:

s1, weighing the raw materials according to the dosage of Fe, Cr, C, Al, Si, Mn and Ce in the alloy composition of the high-carbon Cr bearing steel containing rare earth elements in the claims 1-2; wherein, the raw materials of the aluminum are weighed according to the dosage of more than 0 and less than or equal to 0.05 percent of Al;

s2, smelting in a vacuum induction furnace, comprising:

step 1: charging pure iron, chromium and part of carbon into the furnace;

step 2: vacuumizing the furnace to less than or equal to 1Pa, heating by supplying electricity, and introducing argon into the furnace until the pressure reaches 40-50 KPa;

and step 3: melting down the raw materials in the furnace, adding the residual carbon into the furnace for smelting deoxidation, vacuumizing the furnace, controlling the vacuum degree to be 0-20Pa, and controlling the carbon deoxidation time to be at least more than 20 min;

and 4, step 4: introducing argon into the furnace again to reach 10-20KPa, and adding aluminum, silicon and manganese into the furnace;

step 5, measuring the temperature in the furnace after 3-5min, adjusting the power of the induction furnace according to the measured temperature to enable the temperature in the furnace to reach 1530-1550 ℃, adding cerium into the furnace, and smelting for 3-5 min;

s3 casting remelting electrode bar

Uniformly pouring molten steel smelted by a vacuum induction furnace at a trickle medium speed for 10-20S, and controlling the temperature of the molten steel at 1530-1550 ℃ during pouring to obtain a remelting electrode rod;

s4 electroslag remelting

CaF is adopted for the remelting electrode bar₂-Al₂O₃Carrying out electroslag remelting on the binary slag system to obtain a steel ingot; the slag system is CaF₂65-75wt％，Al₂O₃25-35％；

S5 homogenization Heat treatment

Homogenizing the steel ingot, wherein the homogenizing temperature is 1150 +/-5 ℃, and preserving heat for 3-10 hours to ensure that the internal and external temperatures of the steel ingot are uniform;

s6 forging

The forging conditions are as follows: keeping the temperature at 1200 plus or minus 40 ℃ for 1-3h, keeping the initial forging temperature at 1150 plus or minus 10 ℃, keeping the final forging temperature at 850 plus or minus 10 ℃, keeping the forging ratio at more than or equal to 3, soaking in water intermittently after forging, cooling to 600 ℃ and then cooling in water and air;

s7, spheroidizing annealing treatment;

s8 quenching and tempering treatment

The quenching heating temperature is 810-835 ℃, the tempering adopts low-temperature tempering, and the temperature is 150-250 ℃.

4. The preparation method according to claim 3, wherein in S6, before forging, the surface defects of the steel ingot are removed, and after preheating for a period of time at low temperature, the steel ingot is rapidly heated to 1200 +/-40 ℃ and is kept warm for 1-3 hours.

5. The method as claimed in claim 5, wherein the preheating temperature avoids the blue embrittlement zone at 200-400 ℃; the heating is carried out while avoiding 800 ℃ and 950 ℃, and the maximum heating temperature is not more than 1250 ℃.

6. The method according to claim 3, wherein in S7, isothermal spheroidizing annealing is employed under conditions of: heating to 800 + -10 deg.C, holding for 2-3.5h, rapidly cooling to 700 + -10 deg.C, holding for more than 3.5h, cooling to below 600 deg.C at a cooling rate of 30-50 deg.C/h, and discharging.

7. The method for preparing according to claim 6, wherein the isothermal spheroidizing annealing conditions are: heating to 800 deg.C, holding for 3h, quickly cooling to 700 deg.C, holding for 4h, cooling to below 600 deg.C, discharging, and air cooling.

8. The production method according to claim 3, wherein in S8, the quenching and tempering conditions are as follows: oil quenching is adopted to preserve heat for 30min at 830 ℃, then tempering and heat preservation are carried out for 3h at 160 ℃, and air cooling is carried out.

9. The method of claim 3, wherein 1/2 carbon is added into the vacuum induction furnace, and another 1/2 carbon is added for deoxidation in step 3.

10. The preparation method of claim 3, wherein the purity of the cerium raw material used in the melting process of the vacuum induction furnace is more than or equal to 99.99%.

Technical Field

The invention relates to the technical field of metal materials, in particular to high-carbon chromium bearing steel containing rare earth elements and a preparation method thereof.

Background

The high-carbon chromium bearing steel not only has good wear resistance and contact fatigue resistance, but also has certain elasticity, toughness and good processability, and is mainly used for manufacturing bearings and bearing parts. In order to meet the requirements of severe working conditions and long service life, it is generally required to have higher purity and more uniform tissue morphology. It has been shown that factors affecting the performance of bearing steel can be summarized into two metallurgical related problems: purity and homogeneity of the steel. The purity of the bearing steel means the content and type of inclusions in the steel, including the types and contents of harmful elements, gases and the like. Uniformity of bearing steel refers to uniformity of chemical composition and uniformity of carbides.

The performance gap of domestic bearing materials is mainly expressed in the aspects of purity, organization uniformity and stability, surface hardness, core toughness and the like, and the evaluation of the service behavior of the bearing, so that the contact fatigue life of the bearing is insufficient, and the reliability is reduced; but foreign imported bearings have the disadvantages of high price, fussy channel for goods feeding, long ordering time, uncertain manufacturers, difficult stabilization and updating of products and the like, and restrict the rapid development of high-performance bearing steel and bearing technology in China; therefore, the development of high-performance bearing materials and bearings is urgent and important. Meanwhile, with the current equipment becoming large-scale and oversize, a series of optimization improvements in the aspects of component design and steel purity control are particularly necessary to meet the requirements of high-performance bearings required by the bearing industry and other industries.

Disclosure of Invention

Technical problem to be solved

In view of the defects and shortcomings of the prior art, the invention provides the high-carbon chromium bearing steel containing the rare earth element and the preparation method thereof, and the purity and the mechanical property of the bearing steel material are further improved on the basis of the advantages of low cost, high hardenability and high wear resistance of GCr15SiMn steel.

(II) technical scheme

In order to achieve the purpose, the invention adopts the main technical scheme that:

in a first aspect, the invention provides a high-carbon chromium bearing steel containing rare earth elements, which comprises the following components in percentage by weight: c: 0.95-1.05%; cr: 1.4-1.65%; si: 0.45 to 0.75 percent; mn: 0.95-1.25%; ce: 0.015-0.05%; mo: less than or equal to 0.10 percent; ni is less than or equal to 0.30 percent; cu is less than or equal to 0.25 percent; p is less than or equal to 0.025 percent; s: less than or equal to 0.005 percent; o: less than or equal to 0.001 percent; al: less than or equal to 0.05 percent; ti is less than or equal to 0.003 percent; the balance being Fe and unavoidable impurities.

The main alloy elements of the high-carbon chromium bearing steel are Fe, C, Si, Cr, Mn and Ce. Wherein Mo, Ni, Cu, P, S, O, Al and Ti are elements with the content needing to be controlled. The inevitable impurities are mainly impurities carried by raw materials, and comprise Ca, As, Sn, Sb, Pb and the like. Al is added to the smelting furnace during the preparation process for final deoxidation (controlling the final oxygen content of the product). In addition to the aforementioned 6 main alloying elements and Al, other elements including Mo, Ni, Cu, P, S, O, Ti, Ca, As, Sn, Sb, Pb, etc. are not artificially and actively added, but are introduced from impurities introduced from raw materials or a preparation process.

It should be noted that the composition of the high-carbon chromium bearing steel containing rare earth elements listed above refers to the content of each element in the final bearing steel product; in the preparation process of the bearing steel, the raw materials of the main alloy elements can be prepared according to the composition percentage, and the aluminum can be prepared according to the dosage of more than 0 and less than or equal to 0.05 percent.

In the invention, a proper amount of Ce is added on the basis of GCr15SiMn steel. Ce has low melting point, can have strong affinity with various harmful gases in smelting, and can be combined with the harmful gases. Ce also has strong deoxidation and desulfurization effects, molten steel purification and alloying effects, and can modify inclusions in the steel, thereby improving various properties (including cleanliness and mechanical properties) of the steel. The rare earth used in the invention is pure rare earth Ce with the purity of more than or equal to 99.99 percent.

Wherein, the content of the S element is controlled below 50ppm through an electroslag remelting process; the content of O element is strictly controlled within 10ppm by vacuum induction melting.

According to the preferred embodiment of the present invention, the content of Ce is 0.016% -0.020%. When the addition amount of Ce is 0.016-0.020%, the oxygen content in the bearing steel can be reduced by 56.5-60%, the sulfur content can be reduced by 51.7-55.5%, the impact performance can be improved by 70-74.7%, the tensile strength can be improved by 18-22.2%, and the hardness can be improved by 7.0-8.0%; compared with bearing steel, the mechanical property is obviously improved.

Wherein, the Ce content is in a narrow interval (0.015-0.05%), when the Ce content is less than 0.015%, the inclusion is not enough to deteriorate and the rare earth microalloying effect cannot be achieved; when the Ce content is higher than 0.05%, the inclusion forming element content is increased, so that the number of inclusions in the steel is increased, the size is increased, sharp corners at the edges are obvious, and the performance of the steel is seriously deteriorated.

In a second aspect, the present invention provides a method for preparing a high carbon chromium bearing steel containing a rare earth element, comprising the steps of:

s1, weighing the raw materials according to the dosage of iron, chromium, carbon, aluminum, silicon, manganese and cerium in the alloy composition; in the preparation process, the raw materials of the aluminum are weighed according to the dosage of more than 0 and less than or equal to 0.05 percent of Al, and the purity of the cerium raw material is more than or equal to 99.99 percent;

the content of each element in the final bearing steel product varies slightly but is essentially negligible.

S2, smelting in a vacuum induction furnace, which comprises the following steps:

step 1: charging pure iron, chromium and part of carbon into the furnace;

step 2: vacuumizing the furnace to less than or equal to 1Pa, heating by supplying electricity, and introducing argon into the furnace until the pressure reaches 40-50 KPa;

and step 3: melting down the raw materials in the furnace, adding the residual carbon into the furnace for smelting deoxidation, vacuumizing the furnace, controlling the vacuum degree to be 0-20Pa, and controlling the carbon deoxidation time to be at least more than 20 min;

and 4, step 4: introducing argon into the furnace again to reach 10-20KPa, and adding aluminum, silicon and manganese into the furnace (the aluminum is used for final deoxidation);

step 5, measuring the temperature in the furnace after 3-5min, adjusting the power of the induction furnace according to the measured temperature to enable the temperature in the furnace to reach 1530-1550 ℃, adding cerium into the furnace, and smelting for 3-5 min;

s3 casting remelting electrode bar

Uniformly pouring molten steel smelted by a vacuum induction furnace at a trickle medium speed for 10-20S, and controlling the temperature of the molten steel at 1530-1550 ℃ during pouring to obtain a remelting electrode rod;

s4 electroslag remelting

CaF is adopted for the remelting electrode bar₂-Al₂O₃Carrying out electroslag remelting on the binary slag system to obtain a steel ingot; the slag system is CaF₂65-75wt％，Al₂O₃25-35％；

S5 homogenization Heat treatment

Homogenizing the steel ingot, wherein the homogenizing temperature is 1150 +/-5 ℃, and keeping the temperature for 3-10h (preferably 5h) to ensure that the internal and external temperatures of the steel ingot are uniform;

s6 forging

The forging conditions are as follows: keeping the temperature at 1200 plus or minus 40 ℃ for 1-3h, keeping the initial forging temperature at 1150 plus or minus 10 ℃, keeping the final forging temperature at 850 plus or minus 10 ℃, keeping the forging ratio at more than or equal to 3, soaking in water intermittently after forging, cooling to 600 ℃ and then cooling in water and air;

s7, spheroidizing annealing treatment;

s8 quenching and tempering treatment

The quenching heating temperature is 810-835 ℃, the tempering adopts low-temperature tempering, and the temperature is 150-250 ℃.

According to the preferred embodiment of the invention, in S6, before forging, the surface defects of the steel ingot are removed, and after preheating for a period of time at low temperature, the steel ingot is rapidly heated to 1200 +/-40 ℃ and is kept warm for 1-3 h.

According to the preferred embodiment of the invention, the preheating temperature avoids the blue brittle zone at 200-400 ℃; when heating, the hot brittle area is avoided (800-.

According to the preferred embodiment of the present invention, in S7, isothermal spheroidizing annealing is adopted under the conditions: heating to 800 + -10 deg.C, holding for 2-3.5h, rapidly cooling to 700 + -10 deg.C (A1), holding for a long time (more than 3.5 h), cooling to below 600 deg.C at a cooling rate of 30-50 deg.C/h, and discharging.

According to a preferred embodiment of the present invention, the isothermal spheroidizing annealing conditions are: heating to 800 deg.C, holding for 3 hr, quickly cooling to 700 deg.C (about A1), holding for 4 hr, cooling to below 600 deg.C, and air cooling.

Spheroidizing annealing purpose: reducing the hardness, facilitating the processing and preparing for quenching. Compared with the common spheroidizing annealing, the isothermal spheroidizing annealing can shorten the period, make the spheroidized structure more uniform and strictly control the hardness after annealing.

According to the preferred embodiment of the present invention, in S8, the quenching and tempering conditions are as follows: oil quenching is adopted to preserve heat for 30min at 830 ℃, then tempering and heat preservation are carried out for 3h at 160 ℃, and air cooling is carried out.

The quenching aims to improve the comprehensive properties (hardness, wear resistance, fatigue resistance and the like) of the material and provide a high-quality martensite structure for the subsequent process. The tempering aims to keep the high hardness and wear resistance of the quenched workpiece and reduce the quenching residual stress and brittleness. Tempered martensite is obtained after tempering, namely the structure obtained when the quenched martensite is tempered at low temperature. The quenching and tempering are beneficial to the bearing steel to obtain high hardness and wear resistance.

Typical chemical composition analysis values of the steel of the present invention are shown in tables 1 and 2.

TABLE 1 chemical composition wt% of experimental steels

Table 2 shows the control ranges of harmful elements

(III) advantageous effects

The invention has the beneficial effects that:

on the basis of the advantages of low cost, high hardenability and high wear resistance of GCr15SiMn bearing steel, a proper amount of Ce element is added, and a reasonable smelting process is utilized to strictly control the content (especially the content of S and O) of non-main elements, so that the cleanliness and the mechanical property of the GCr15SiMn bearing steel are further improved, a novel high-carbon chromium bearing steel is obtained, and the requirement of a high-performance bearing material is met.

The invention optimizes the alloy components of the bearing steel and combines the improvement of the preparation process to obtain the technical effects that: the high-carbon chromium bearing steel material not only has low oxygen and sulfur contents, but also can obtain excellent shock resistance, high hardness, high wear resistance and high tensile strength. Experiments prove that compared with the existing GCr15SiMn bearing steel, the improved GCr15SiMn bearing steel provided by the invention has the advantages that the purity and the mechanical property are obviously improved, the impact property of the bearing steel is optimally improved by over 70%, the tensile strength is optimally improved by over 20%, and the hardness is optimally improved by over 7%.

Detailed Description

For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail below with reference to specific embodiments. The contents of the respective alloying elements in the following examples are in mass percent.

Example 1

The embodiment provides a novel rare earth-containing high-carbon chromium bearing steel, and the alloy element composition of the novel rare earth-containing high-carbon chromium bearing steel is designed as follows: c: 1.02 percent; cr: 1.56 percent; si: 0.56 percent; mn: 1.09%; ce: 0.016 percent; mo: less than or equal to 0.10 percent; ni is less than or equal to 0.30 percent; cu is less than or equal to 0.25 percent; p is less than or equal to 0.025 percent; s: 0.0014%; o: 0.0007 percent; al is less than or equal to 0.05 percent; ti is less than or equal to 0.003 percent; the balance being Fe and unavoidable impurities.

The preparation process of the novel high-carbon chromium bearing steel comprises the following steps:

(1) weighing the raw materials according to the dosage of iron, chromium, carbon, aluminum, silicon, manganese and cerium in the components; the raw materials of the aluminum are weighed according to 0.03 percent, and the purity of the cerium is more than or equal to 99.99 percent.

After the raw materials are weighed according to the components and are smelted, the remelted electrode bar is poured, the electroslag remelting, the homogenization heat treatment, the forging, the spheroidizing annealing treatment, the quenching and the tempering treatment are carried out, and the content of each element in the finally obtained bearing steel product has small change but can be basically ignored.

(2) Smelting in a vacuum induction furnace, and operating according to the following steps:

charging: charging pure iron + Cr +1/2C along with the furnace; a storage bin: 1/2C + Al + Si + Mn + rare earth Ce;

secondly, vacuumizing to less than or equal to 1Pa, heating by power supply, and introducing argon into the furnace to 50 KPa;

thirdly, after melting down, adding C in a storage bin, vacuumizing, controlling the vacuum degree to be below 20Pa, and performing carbon deoxidation for 30 minutes;

fourthly, introducing argon into the furnace again to 10KPa, and adding Al, Si and Mn in the storage bin in sequence;

measuring the temperature after 3-5 minutes, adjusting the power to make the temperature reach 1530 ℃ and 1550 ℃, and adding rare earth Ce;

(3) pouring remelting electrode bar

Uniformly pouring molten steel subjected to vacuum induction melting at a trickle medium speed for 20 seconds, controlling the pouring temperature to be 1540-1550 ℃, and obtaining a remelting electrode bar for the first time;

(4) electroslag remelting

Using CaF₂-Al₂O₃And carrying out electroslag remelting on the binary slag system to obtain the steel ingot. The slag system mass ratio is as follows: CaF₂:70％，Al₂O₃:30％。

(5) Homogenizing heat treatment

Homogenizing the steel ingot before forging at 1150 +/-5 deg.c for 5 hr to ensure homogeneous temperature inside and outside the steel ingot.

(6) Forging

Keeping the temperature at 1200 ℃ for 2h, the initial forging temperature is 1150 ℃, the final forging temperature is 850 ℃, the forging ratio is not less than 3, adopting intermittent immersion after forging, cooling to 600 ℃, discharging water, and cooling in air.

Attention points in the forging process:

firstly, surface defects are removed before forging, and the steel is quickly heated after preheating as much as possible.

② during warm processing (preheating), a blue brittle area of 200 and 400 ℃ should be avoided. During thermal processing (heating up), the temperature should be avoided from entering the hot brittle region at 800 ℃ and 950 ℃ and the high temperature brittle region (more than 1250 ℃) as much as possible.

(7) Spheroidizing annealing treatment

The spheroidizing annealing process is isothermal spheroidizing annealing: heating to 800 deg.C, holding for 3 hr, quickly cooling to 700 deg.C (about A1), holding for 4 hr, cooling to below 600 deg.C, and air cooling.

f) Quenching and tempering treatment

Quenching and tempering are as follows: oil quenching is adopted, the temperature is kept at 830 ℃ for 30min, the temperature is kept at 160 ℃ for 3h for tempering, and then air cooling is carried out.

Example 2

The embodiment provides a novel rare earth-containing high-carbon chromium bearing steel, and the alloy element composition of the novel rare earth-containing high-carbon chromium bearing steel is designed as follows: c: 1.02 percent; cr: 1.55 percent; si: 0.59 percent; mn: 1.09%; ce: 0.029%; mo: less than or equal to 0.10 percent; ni is less than or equal to 0.30 percent; cu is less than or equal to 0.25 percent; p is less than or equal to 0.025 percent; s: 0.0012%; o: 0.0006 percent; al is less than or equal to 0.05 percent; ti is less than or equal to 0.003 percent; the balance being Fe and unavoidable impurities.

In this example, the process for the preparation of high carbon chromium bearing steel is described in example 1.

Example 3

The embodiment provides a novel rare earth-containing high-carbon chromium bearing steel, and the alloy element composition of the novel rare earth-containing high-carbon chromium bearing steel is designed as follows: c: 1.02 percent; cr: 1.56 percent; si: 0.59 percent; mn: 1.10 percent; ce: 0.048 percent; mo: less than or equal to 0.10 percent; ni is less than or equal to 0.30 percent; cu is less than or equal to 0.25 percent; p is less than or equal to 0.025 percent; s: 0.0009 percent; o: 0.0004 percent; al is less than or equal to 0.05 percent; ti is less than or equal to 0.003 percent; the balance being Fe and unavoidable impurities.

In this example, the process for the preparation of high carbon chromium bearing steel is described in example 1.

Comparative example 1

The alloy element composition of the high carbon chromium bearing steel of comparative example 1 was: c: 1.02 percent; cr: 1.56 percent; si: 0.56 percent; mn: 1.07 percent; mo: less than or equal to 0.10 percent; ni is less than or equal to 0.30 percent; cu is less than or equal to 0.25 percent; p is less than or equal to 0.025 percent; s: 0.0029%; o: 0.0016 percent; al is less than or equal to 0.05 percent; ti is less than or equal to 0.003 percent; the balance being Fe and unavoidable impurities. The preparation method and conditions were the same as in example 1.

Comparative example 2

The alloy element composition of the high carbon chromium bearing steel of comparative example 2 was: c: 1.02 percent; cr: 1.56 percent; si: 0.56 percent; mn: 1.09%; ce: 0.08 percent; mo: less than or equal to 0.10 percent; ni is less than or equal to 0.30 percent; cu is less than or equal to 0.25 percent; p is less than or equal to 0.025 percent; s: 0.0014%; o: 0.0007 percent; al is less than or equal to 0.05 percent; ti is less than or equal to 0.003 percent; the balance being Fe and unavoidable impurities. The preparation method and conditions were the same as in example 1.

Comparative example 3

The alloy element composition of the high carbon chromium bearing steel of comparative example 3 was: c: 1.02 percent; cr: 1.56 percent; si: 0.56 percent; mn: 1.09%; ce: 0.15 percent; mo: less than or equal to 0.10 percent; ni is less than or equal to 0.30 percent; cu is less than or equal to 0.25 percent; p is less than or equal to 0.025 percent; s: 0.0014%; o: 0.0007 percent; al is less than or equal to 0.05 percent; ti is less than or equal to 0.003 percent; the balance being Fe and unavoidable impurities. The preparation method and conditions were the same as in example 1.

Comparative example 4

The alloy element composition of the high carbon chromium bearing steel of comparative example 4 was: c: 1.02 percent; cr: 1.56 percent; si: 0.56 percent; mn: 1.09%; ce: 0.010%; mo: less than or equal to 0.10 percent; ni is less than or equal to 0.30 percent; cu is less than or equal to 0.25 percent; p is less than or equal to 0.025 percent; s: 0.0014%; o: 0.0007 percent; al is less than or equal to 0.05 percent; ti is less than or equal to 0.003 percent; the balance being Fe and unavoidable impurities. The preparation method and conditions were the same as in example 1.

The bearing steel of each example above was measured for oxygen and sulfur content, temper hardness, tensile strength, and impact resistance (charpy unnotched impact energy), and the results are shown in the following table:

from example 1, it can be seen that when 0.016% Ce is added, the content and performance of harmful elements in the bearing steel are as follows: compared with comparative example 1, the oxygen content is reduced by 56.3%, the sulfur content is reduced by 51.7%, the impact resistance is improved by 73.6%, the tensile strength is improved by 25.4%, and the hardness is improved by 7.6%. The purity and the mechanical property of the novel rare earth-containing high-carbon chromium bearing steel of the embodiment are superior to those of comparative example 1.

From example 2, it can be seen that when 0.029% Ce is added, the content and properties of harmful elements in the bearing steel are as follows: compared with comparative example 1, the oxygen content is reduced by 62.5%, the sulfur content is reduced by 58.6%, the impact resistance is improved by 47.2%, the tensile strength is improved by 13.9%, and the hardness is improved by 6.5%. The purity and the mechanical property of the novel rare earth-containing high-carbon chromium bearing steel of the embodiment are superior to those of comparative example 1.

From example 3, it can be seen that when 0.048% Ce is added, the content and properties of harmful elements in the bearing steel are as follows: compared with comparative example 1, the oxygen content is reduced by 75%, the sulfur content is reduced by 69%, the impact resistance is improved by 18.9%, the tensile strength is improved by 13.5%, and the hardness is improved by 5.6%. The purity and the mechanical property of the novel rare earth-containing high-carbon chromium bearing steel of the embodiment are superior to those of comparative example 1.

It is understood from examples 1 to 3 that, when the Ce content is higher than 0.05%, the content of the harmful element in the bearing steel is remarkably reduced, but the impact resistance, tensile strength, and hardness of the bearing steel are not remarkably improved, and even a tendency to decrease begins to appear, as compared with comparative examples 2 to 4. And when the Ce content is lower than 0.015 percent, the content of harmful elements in the bearing steel is not obviously reduced, and the impact property, the tensile strength and the hardness of the bearing steel are not obviously improved. Therefore, when Ce0.015-0.05% is added to the existing GCr15SiMn bearing steel, the harmful alloy elements in the bearing steel product can be effectively reduced, and various mechanical properties of the bearing steel are obviously improved.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.