WO2018103088A1

WO2018103088A1 - Bearing steel heat treatment process

Info

Publication number: WO2018103088A1
Application number: PCT/CN2016/109272
Authority: WO
Inventors: 孙振田; 马飞
Original assignee: 孙振田; 马飞
Priority date: 2016-12-09
Filing date: 2016-12-09
Publication date: 2018-06-14

Abstract

A bearing steel heat treatment process, comprising: normalizing treatment; annealing treatment; quenching treatment; freezing treatment; and tempering treatment. Segmented heating is used for normalizing, annealing, and tempering. Heat-treated bearing steel has high strength and high hardness.

Description

Bearing steel heat treatment process

Technical field

The invention relates to the technical field of heat treatment of bearing steel, in particular to a heat treatment process of bearing steel.

Background technique

The existing problem in the heat treatment process of the existing bearing steel is that the annealing speed is too fast, which leads to the strong brittleness of the bearing steel. After the bearing is made into a bearing, the bearing bears not only the axial force due to the long-term rotational motion of the shaft. There is also a portion of the radial force that collides with the bearing and the bearing will break after a period of use. Because of the quenching and low temperature tempering in the heat treatment process of bearing steel, the strength, hardness, wear resistance and fatigue resistance of bearing steel are relatively poor. Therefore, we propose a heat treatment process for bearing steel.

Summary of the invention

Based on the technical problems existing in the background art, the present invention proposes a heat treatment process for bearing steel.

The heat treatment process of a bearing steel proposed by the invention comprises the following steps:

S1, normalizing treatment: raise the temperature in the furnace to 450-650 ° C, put the bearing steel into the furnace, raise the temperature in the furnace to 720-820 ° C at 20-30 ° C / h, keep warm 1- 2h, the bearing steel is cooled in the air by a fan;

S2, annealing treatment: the bearing steel is heated to 520-680 ° C in the furnace, the temperature is kept for 0.5-1 h, and then the temperature in the furnace is lowered to 500-550 ° C at a rate of 30-40 ° C / h, after 0.5-1 h of heat preservation, Raise the temperature in the furnace to 700-800 ° C at a rate of 20-30 ° C / h, and finally put the furnace inside The temperature is reduced to 500-600 ° C at a rate of 50-60 ° C / h, and is cooled with the furnace;

S3, quenching treatment: the bearing steel is heated in the furnace to a temperature of 300-500 ° C, after 0.5-1 h of heat preservation, the bearing steel is taken out and quenched in oil, the temperature of the oil is 120-200 ° C, lasting 10-30 min;

S4, tempering treatment: the quenched bearing steel is first frozen and then placed in a tempering furnace, the temperature in the furnace is raised to 100-150 ° C for 40-70 min, and then the temperature in the furnace is raised to 160- 180 ° C, lasting 20-40 ° C, and finally reduce the temperature in the furnace to 90-140 ° C for 10-30 min, take out and cool naturally in the air;

S5, heat preservation treatment: the bearing steel cooled in S4 is placed in an incubator, and the heat treatment is completed by holding at a temperature of 100-120 ° C for 3-5 hours.

Preferably, in the S1, the fan is disposed around the bearing steel.

Preferably, in the S1, the fan is equidistantly disposed on one side of the bearing steel.

Preferably, in the S2, the bearing steel is heated to 600 ° C in the furnace, the temperature is maintained for 0.75 h, and the temperature in the furnace is lowered to 525 ° C at a rate of 35 ° C / h. After the temperature is maintained for 0.75 h, the temperature in the furnace is set. The temperature was raised to 750 ° C at a rate of 25 ° C / h, and finally the temperature in the furnace was lowered to 550 ° C at a rate of 55 ° C / h, and cooled with the furnace.

Preferably, in the S3, the bearing steel is heated in the furnace to a temperature of 400 ° C, and after the heat preservation for 0.75 h, the bearing steel is taken out and quenched in the oil, and the temperature of the oil is 160 ° C for 20 min.

Preferably, in the S4, the freezing treatment is: freezing the bearing steel at a temperature between -140 ° C and -90 ° C.

In the present invention, the number of quenching is appropriately increased, and the relevant parameters for changing the quenching are optimized, first Through normalizing treatment, the temperature in the furnace is raised, and the temperature is increased after a period of time, and then cooled by a fan, and then subjected to corresponding annealing, quenching and tempering treatment, and finally the bearing steel is insulated to ensure the strength of the bearing steel. The hardness is improved, and the wear resistance and fatigue resistance of the bearing steel are improved. The heat treatment process of the bearing steel of the invention is convenient to operate, and the bearing steel after the heat treatment has the advantages of high strength and high hardness compared with the conventional processed bearing steel. More wear and fatigue resistance, improved performance.

detailed description

The invention is further illustrated below in conjunction with specific embodiments.

Embodiment 1

S1, normalizing treatment: the temperature in the furnace is raised to 450 ° C, the bearing steel is placed in the furnace, the temperature in the furnace is raised to 720 ° C at a rate of 20 ° C / h, and the temperature is kept for 1 h, and the bearing steel is discharged in the air. Cooled by a fan;

S2, annealing treatment: the bearing steel is heated to 520 ° C in the furnace, kept for 0.5 h, and then the temperature in the furnace is reduced to 500 ° C at a rate of 30 ° C / h, after 0.5 h of heat preservation, the temperature in the furnace is 20 ° C The speed of /h rises to 700 ° C, and finally the temperature in the furnace is lowered to 500 ° C at a rate of 50 ° C / h, and is cooled with the furnace;

S3, quenching treatment: the bearing steel is heated in the furnace to a temperature of 300 ° C, after 0.5 h of heat preservation, the bearing steel is taken out and quenched in oil, the temperature of the oil is 120 ° C for 10 min;

S4, tempering treatment: the quenched bearing steel is first frozen and then placed in a tempering furnace, the temperature in the furnace is raised to 100 ° C for 40 min, and then the temperature in the furnace is raised to 160 ° C for 20 ° C Finally, the temperature in the furnace is lowered to 90 ° C for 10 min, and taken out in the air. Natural cooling;

S5, heat preservation treatment: the bearing steel cooled in S4 is placed in an incubator, and the heat treatment is completed by holding at a temperature of 100 ° C for 3 hours.

Embodiment 2

S1, normalizing treatment: the temperature in the furnace is raised to 500 ° C, the bearing steel is placed in the furnace, the temperature in the furnace is raised to 740 ° C at a rate of 22 ° C / h, and the temperature is kept for 1.2 h, and the bearing steel is discharged in the air. Cooled by a fan;

S2, annealing treatment: the bearing steel is heated to 540 ° C in the furnace, kept for 0.6 h, and then the temperature in the furnace is reduced to 510 ° C at a rate of 32 ° C / h, after holding for 0.6 h, the temperature in the furnace is 22 ° C The speed of /h rises to 720 ° C, and finally the temperature in the furnace is reduced to 520 ° C at a rate of 52 ° C / h, and is cooled with the furnace;

S3, quenching treatment: the bearing steel is heated in the furnace to a temperature of 350 ° C, after holding for 0.6 h, the bearing steel is taken out and quenched in oil, the temperature of the oil is 130 ° C, lasting 15 min;

S4, tempering treatment: the quenched bearing steel is first frozen and then placed in a tempering furnace, the temperature in the furnace is raised to 110 ° C for 50 min, and then the temperature in the furnace is raised to 165 ° C for 25 ° C Finally, the temperature in the furnace is lowered to 100 ° C for 15 min, and taken out and naturally cooled in the air;

S5, heat preservation treatment: the bearing steel cooled in S4 is placed in an incubator, and heat treatment is completed at 105 ° C for 3.5 h.

Embodiment 3

S1, normalizing treatment: raise the temperature in the furnace to 550 ° C, put the bearing steel into the furnace, raise the temperature in the furnace to 770 ° C at 25 ° C / h, keep warm for 1.5 h, and the bearing steel is baked in the air. Cooled by a fan;

S2, annealing treatment: the bearing steel is heated to 600 ° C in the furnace, the temperature is kept for 0.75 h, and the temperature in the furnace is reduced to 525 ° C at a rate of 35 ° C / h. After the heat preservation for 0.75 h, the temperature in the furnace is 25 ° C. The speed of /h rises to 750 ° C, and finally the temperature in the furnace is lowered to 550 ° C at a rate of 55 ° C / h, and is cooled with the furnace;

S3, quenching treatment: the bearing steel is heated in the furnace to a temperature of 400 ° C, after 0.75 h of heat preservation, the bearing steel is taken out and quenched in oil, the temperature of the oil is 160 ° C for 20 min;

S4, tempering treatment: the quenched bearing steel is first frozen and then placed in a tempering furnace, the temperature in the furnace is raised to 125 ° C for 55 min, and then the temperature in the furnace is raised to 170 ° C for 30 ° C Finally, the temperature in the furnace is lowered to 115 ° C for 20 min, and taken out and naturally cooled in the air;

S5, heat preservation treatment: the bearing steel cooled in S4 is placed in an incubator, and the heat treatment is completed by holding at a temperature of 110 ° C for 4 hours.

Embodiment 4

S1, normalizing treatment: the temperature in the furnace is raised to 600 ° C, the bearing steel is placed in the furnace, the temperature in the furnace is raised to 800 ° C at a rate of 28 ° C / h, the heat is maintained for 1.8 h, and the bearing steel is discharged in the air. Cooled by a fan;

S2, annealing treatment: the bearing steel is heated to 640 ° C in the furnace, and the temperature is kept for 0.9 h. Then the temperature in the furnace is lowered to 540 ° C at a rate of 38 ° C / h. After the temperature is maintained for 0.9 h, the temperature in the furnace is set. Raise to 780 ° C at a rate of 28 ° C / h, and finally reduce the temperature in the furnace to 580 ° C at a rate of 58 ° C / h, with the furnace cooling;

S3, quenching treatment: the bearing steel is heated in the furnace to a temperature of 450 ° C, after holding for 0.9 h, the bearing steel is taken out and quenched in oil, the temperature of the oil is 180 ° C, lasting 25 min;

S4, tempering treatment: the quenched bearing steel is first frozen and then placed in a tempering furnace, the temperature in the furnace is raised to 140 ° C for 60 min, and then the temperature in the furnace is raised to 175 ° C for 35 ° C Finally, the temperature in the furnace is lowered to 130 ° C for 25 min, and taken out and naturally cooled in the air;

S5, heat preservation treatment: the bearing steel cooled in S4 is placed in an incubator, and the heat treatment is completed by holding at a temperature of 115 ° C for 4.5 hours.

Embodiment 5

S1, normalizing treatment: raise the temperature in the furnace to 650 ° C, put the bearing steel into the furnace, raise the temperature in the furnace to 820 ° C at 30 ° C / h, keep warm for 2 h, and the bearing steel is baked in the air. Cooled by a fan;

S2, annealing treatment: the bearing steel is heated to 680 ° C in the furnace, kept for 1 h, and then the temperature in the furnace is reduced to 550 ° C at a rate of 40 ° C / h. After 1 h of heat preservation, the temperature in the furnace is 30 ° C / h. The speed is increased to 800 ° C, and finally the temperature in the furnace is reduced to 600 ° C at a rate of 60 ° C / h, and cooled with the furnace;

S3, quenching treatment: the bearing steel is heated in the furnace to a temperature of 500 ° C, after 1 h of heat preservation, the bearing steel is taken out and quenched in oil, the temperature of the oil is 200 ° C, lasting 30 min;

S4, tempering treatment: the quenched bearing steel is first frozen and then placed in a tempering furnace. The temperature in the furnace was raised to 150 ° C for 70 min, then the temperature in the furnace was raised to 180 ° C, continued at 40 ° C, and finally the temperature in the furnace was lowered to 140 ° C for 30 min, and taken out and naturally cooled in the air;

S5, heat preservation treatment: the bearing steel cooled in S4 is placed in an incubator, and the heat treatment is completed by holding at a temperature of 120 ° C for 5 hours.

The heat treatment process of the bearing steel of the invention is convenient to operate, and the bearing steel after the heat treatment has the advantages of high strength and high hardness compared with the traditional processed bearing steel, is more wear-resistant and fatigue-resistant, and has improved performance.

The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any technical person skilled in the art within the technical scope disclosed by the present invention, the technical solution according to the present invention Equivalent substitutions or modifications of the inventive concept are intended to be included within the scope of the invention.

Claims

A bearing steel heat treatment process is characterized in that it comprises the following steps:

S1, normalizing treatment: raise the temperature in the furnace to 450-650 ° C, put the bearing steel into the furnace, raise the temperature in the furnace to 720-820 ° C at 20-30 ° C / h, keep warm 1- 2h, the bearing steel is cooled in the air by a fan;

S2, annealing treatment: the bearing steel is heated to 520-680 ° C in the furnace, the temperature is kept for 0.5-1 h, and then the temperature in the furnace is lowered to 500-550 ° C at a rate of 30-40 ° C / h, after 0.5-1 h of heat preservation, Raise the temperature in the furnace to 700-800 ° C at a rate of 20-30 ° C / h, and finally reduce the temperature in the furnace to 500-600 ° C at a rate of 50-60 ° C / h, and cool with the furnace;

S3, quenching treatment: the bearing steel is heated in the furnace to a temperature of 300-500 ° C, after 0.5-1 h of heat preservation, the bearing steel is taken out and quenched in oil, the temperature of the oil is 120-200 ° C, lasting 10-30 min;

S4, tempering treatment: the quenched bearing steel is first frozen and then placed in a tempering furnace, the temperature in the furnace is raised to 100-150 ° C for 40-70 min, and then the temperature in the furnace is raised to 160- 180 ° C, lasting 20-40 ° C, and finally reduce the temperature in the furnace to 90-140 ° C for 10-30 min, take out and cool naturally in the air;

S5, heat preservation treatment: the bearing steel cooled in S4 is placed in an incubator, and the heat treatment is completed by holding at a temperature of 100-120 ° C for 3-5 hours.
A heat treatment process for a bearing steel according to claim 1, wherein in the S1, the fan is disposed around the bearing steel.
A heat treatment process for a bearing steel according to claim 1, wherein in the S1, the fan is equidistantly disposed on one side of the bearing steel.
A heat treatment process for a bearing steel according to claim 1, wherein In the S2, the bearing steel is heated to 600 ° C in the furnace, the temperature is maintained for 0.75 h, and the temperature in the furnace is lowered to 525 ° C at a rate of 35 ° C / h. After the temperature is maintained for 0.75 h, the temperature in the furnace is 25 ° C. The speed of /h rises to 750 ° C, and finally the temperature in the furnace is lowered to 550 ° C at a rate of 55 ° C / h, and is cooled with the furnace.
The heat treatment process for a bearing steel according to claim 1, wherein in the S3, the bearing steel is heated in the furnace to a temperature of 400 ° C, and after the heat is maintained for 0.75 h, the bearing steel is taken out and quenched in the oil. The temperature of the oil was 160 ° C for 20 min.
A heat treatment process for a bearing steel according to claim 1, wherein in said S4, the freezing treatment is: freezing the bearing steel at a temperature between -140 ° C and -90 ° C.