Special heat treatment process for improving wear resistance of workpiece

Abstract

The invention relates to the technical field of workpiece heat treatment, in particular to a special heat treatment process for improving the wear resistance of a workpiece. The method comprises the following steps: S1, cleaning a workpiece, and blow-drying the workpiece by using dry compressed air after the workpiece is cleaned; s2, performing 3D scanning on the workpiece to obtain the surface profile of the heat treatment area, obtaining data of the surface area of the workpiece and the area of the laser quenching area, establishing a fitting equation between the laser quenching parameters and the temperature of the heat treatment area, and determining a control rule of the laser quenching parameters along with the temperature of the laser quenching area according to the established fitting equation, the method can effectively solve the problems that deformation is prone to occurring during existing gas nitriding treatment, the flatness of a product is affected, meanwhile, the process time is long when a deep hardened layer needs to be obtained, and the surface hardness is not uniform.

Description

Technical Field

[0001] The invention relates to the technical field of workpiece heat treatment, in particular to a special heat treatment process for improving the wear resistance of a workpiece. Background Art

[0002] The original process of the welding tooling platform is to use Q355 material for welding, process the size, and then perform gas nitriding treatment to improve the wear resistance and corrosion resistance of the surface. However, the gas nitriding treatment still has some shortcomings, specifically: the existing gas nitriding treatment is more likely to cause deformation, affecting the flatness of the product, the process time is very long when a deep hardened layer is required, and the surface hardness is uneven.

[0003] Therefore, a special heat treatment process for improving the wear resistance of a workpiece is needed to solve the problems raised in the above background technology. Summary of the invention

[0004] The object of the present invention is to provide a special heat treatment process for improving the wear resistance of a workpiece, so as to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A special heat treatment process for improving the wear resistance of a workpiece comprises the following steps;

[0007] S1, cleaning the workpiece, drying it with dry compressed air, and marking the area on the surface of the workpiece that needs heat treatment;

[0008] S2, performing 3D scanning on the workpiece to obtain the surface profile of the heat treatment area, obtaining the surface area of ​​the workpiece and the area data of the laser quenching area, establishing a fitting equation between the laser quenching parameter and the temperature of the heat treatment area, determining the control rule of the laser quenching parameter with the temperature of the laser quenching area according to the established fitting equation, inputting the control rule into the controller of the laser quenching device, placing the workpiece into the laser quenching device, and the laser quenching device performing laser quenching treatment on the workpiece;

[0009] S3, taking out the workpiece after treatment, cooling it to room temperature, polishing the quenched area on the workpiece surface to remove the quenching oxide scale, sandblasting the nitrided area on the workpiece surface, adjusting the surface roughness of the nitrided area on the workpiece surface, and then coating the non-nitrided area on the workpiece surface for protection. After drying, the treated workpiece is placed in a nitriding furnace and subjected to gas nitriding treatment. After the treatment is completed, the workpiece is taken out and cleaned, and then packaged and shipped.

[0010] As a preferred solution of the present invention, the cleaning agent used for cleaning the workpiece in S1 is industrial alcohol or metal cleaning agent, and the percentage concentration of industrial alcohol is 95%-97%, and the flow rate of dry compressed air when blowing the workpiece dry is 2-3.12m / s.

[0011] As a preferred solution of the present invention, the specific method of establishing the fitting equation between the laser quenching parameters and the temperature of the heat treatment area in S2 is: adjusting the temperature of the laser quenching area of ​​the laser quenching mechanism, obtaining the quenching parameters corresponding to different quenching temperatures of the device, establishing a relationship between the temperature of the laser quenching area and the laser quenching parameters, and fitting the relationship using a nonlinear fitting method of data to obtain a fitting equation Where P is the laser power density quenching, V is the laser scanning speed, T is the quenching temperature, K 1 , K 2 is the fitting coefficient, Wherein θ is the average value of the normal inclination angles at different positions of the laser quenching area of ​​the workpiece.

[0012] As a preferred solution of the present invention, the specific method of determining the control rule of the laser quenching parameters with the laser quenching area temperature according to the established fitting equation in S2 is: the surface temperature of the workpiece is determined as the laser quenching area temperature T at the initial moment 0 , using the fitting equation to obtain the fitting equation of laser quenching at time t+1 Among them, A, B, and C are the coefficients of laser quenching parameters at time t+1. According to the fitting equation at time t+1 and fixing the laser scanning speed v, the PT control rule is obtained. According to the fitting equation at time t+1 and fixing the laser power density P, the vT control rule is obtained.

[0013] As a preferred solution of the present invention, the coating used in the S3 is ANO-2 type. Distilled water needs to be added to the coating before use, and the coating is heated in a water bath at 47-53°C and stirred for dilution. The coating is applied in layers, and the number of layers is at least twice. Before coating, the small holes on the non-nitrided surface are blocked with asbestos ropes. The drying temperature is 80-100°C, and the drying time is 15-30 minutes.

[0014] As a preferred solution of the present invention, the air pressure of the sand blasting in S3 is ≤0.2Mpa, the sand particle size of the sand blasting is 150-200 mesh, the sand is corundum sand, and the roughness of the nitriding area on the workpiece surface after the sand blasting treatment is less than or equal to 0.8μm.

[0015] As a preferred solution of the present invention, the specific method of gas nitriding treatment of the workpiece is: suspending the workpiece in a nitriding furnace, exhausting ammonia into the nitriding furnace until the ammonia decomposition rate in the nitriding furnace is zero, heating the nitriding furnace to 400°C, keeping it warm for 1-2 hours, controlling the nitrogen in the furnace to be stable, then heating the nitriding furnace to 500-530°C and continuing to control the nitrogen in the furnace to be stable, keeping it warm for 10-50 hours, and then cooling it.

[0016] As a preferred solution of the present invention, the ammonia decomposition rate during the insulation process of the nitriding furnace is 30% to 50%. The cooling treatment method is to pass ammonia and nitrogen into the nitriding furnace and cool it to 80°C, then take the workpiece out of the nitriding furnace and air cool it to room temperature.

[0017] As a preferred solution of the present invention, the method for controlling the stability of nitrogen in the furnace is: obtaining process parameters such as the partial pressure of ammonia and hydrogen in the nitriding furnace, substituting the process parameters into the nitrogen potential value formula Kn=P(NH 3 ) / P(H 2 )^1.5, where Kn is the nitrogen potential value, P(NH 3 ) is the partial pressure of ammonia in the nitriding furnace, P(H 2 ) is the partial pressure of hydrogen in the nitriding furnace. The nitrogen potential value is calculated, and the measured nitrogen potential value is compared with the threshold value set by the process to obtain the deviation value. The flow rate of ammonia and hydrogen entering the nitriding furnace is controlled according to the deviation value.

[0018] As a preferred solution of the present invention, the laser quenching treatment device in S3 is a fiber laser with a core diameter of 600um, a wavelength of 1080nm, and a focusing focal length of 400mm. The laser quenching head adopts the integral principle or the DOE diffraction optical principle to shape the light beam and output a rectangular homogenized spot with a spot size of 100*2mm, 50*2mm, or 15*1.5mm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. In the present invention, a surface profile of a heat treatment area is obtained by performing 3D scanning on the workpiece, the surface area of ​​the workpiece and the area data of the laser quenching area are obtained, a fitting equation between the laser quenching parameter and the temperature of the heat treatment area is established, and a control rule of the laser quenching parameter with the temperature of the laser quenching area is determined according to the established fitting equation, and the control rule is input into a controller of a laser quenching device, and the workpiece is placed in the laser quenching device, and the laser quenching device performs laser quenching treatment on the workpiece, and the workpiece after the treatment is taken out, and after cooling to room temperature, the quenching area of ​​the workpiece surface is polished to remove the quenching oxide scale, and the nitriding area on the surface of the workpiece is sandblasted to adjust the surface roughness of the nitriding area on the surface of the workpiece, and then the non-nitriding area on the surface of the workpiece is coated for protection, and after drying, the treated workpiece is placed in a nitriding furnace, and the workpiece is subjected to gas nitriding treatment, and a layer of martensitic structure is first obtained on the surface of the workpiece by laser quenching, and then the surface oxide scale generated by quenching is polished to remove, and then a short time of gas nitriding is performed, which can greatly shorten the nitriding time, reduce the process cycle, and reduce the risk of deformation.

[0021] 2. In the present invention, by obtaining the surface area of ​​the workpiece and the area data of the laser quenching area, a fitting equation between the laser quenching parameters and the temperature of the heat treatment area is established, and the control rule of the laser quenching parameters and the temperature of the laser quenching area is determined according to the established fitting equation. The control rule is input into the controller of the laser quenching device, and the laser quenching parameters are adjusted by using a single variable PT control rule - or a single variable vT control rule. The input laser energy can be accurately controlled to offset the influence of various other factors such as the size, shape structure, heating state and cooling conditions of the substrate to be quenched on the temperature of the laser quenching area. At the same time, during gas nitriding, process parameters such as the partial pressure of ammonia and hydrogen in the nitriding furnace are obtained, and the process parameters are substituted into the nitrogen potential value formula to calculate the nitrogen potential value. The measured nitrogen potential value is compared with the threshold value set by the process to obtain a deviation value. The flow rate of ammonia and hydrogen entering the nitriding furnace is controlled according to the deviation value, which can more accurately control the nitrogen pressure and flow rate in the nitriding furnace to ensure the gas nitriding effect. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] Embodiment, the present invention provides a technical solution:

[0024] A special heat treatment process for improving the wear resistance of a workpiece comprises the following steps;

[0025] S1, cleaning the workpiece, drying it with dry compressed air, and marking the area on the surface of the workpiece that needs heat treatment;

[0026] S2, performing 3D scanning on the workpiece to obtain the surface profile of the heat treatment area, obtaining the surface area of ​​the workpiece and the area data of the laser quenching area, establishing a fitting equation between the laser quenching parameter and the temperature of the heat treatment area, determining the control rule of the laser quenching parameter with the temperature of the laser quenching area according to the established fitting equation, inputting the control rule into the controller of the laser quenching device, placing the workpiece into the laser quenching device, and the laser quenching device performing laser quenching treatment on the workpiece;

[0027] S3, taking out the workpiece after treatment, cooling it to room temperature, polishing the quenched area on the workpiece surface to remove the quenching oxide scale, sandblasting the nitrided area on the workpiece surface, adjusting the surface roughness of the nitrided area on the workpiece surface, and then coating the non-nitrided area on the workpiece surface for protection. After drying, the treated workpiece is placed in a nitriding furnace and subjected to gas nitriding treatment. After the treatment is completed, the workpiece is taken out and cleaned, and then packaged and shipped.

[0028] Furthermore, the cleaning agent used for cleaning the workpiece in S1 is industrial alcohol or metal cleaning agent, and the percentage concentration of industrial alcohol is 95%-97%, and the flow rate of dry compressed air when blowing the workpiece dry is 2-3.12m / s.

[0029] Furthermore, the specific method for establishing the fitting equation between the laser quenching parameters and the temperature of the heat treatment area in S2 is: adjusting the temperature of the laser quenching area of ​​the laser quenching mechanism, obtaining the quenching parameters corresponding to different quenching temperatures of the device, establishing a relationship between the temperature of the laser quenching area and the laser quenching parameters, and fitting the relationship using a nonlinear fitting method of data to obtain a fitting equation Where P is the laser power density quenching, V is the laser scanning speed, T is the quenching temperature, K 1 , K 2 is the fitting coefficient, Wherein θ is the average value of the normal inclination angles at different positions of the laser quenching area of ​​the workpiece.

[0030] Furthermore, the specific method of determining the control rule of the laser quenching parameters with the laser quenching area temperature according to the established fitting equation in S2 is: the surface temperature of the workpiece is determined as the laser quenching area temperature T at the initial moment 0 , using the fitting equation to obtain the fitting equation of laser quenching at time t+1 Among them, A, B, and C are the coefficients of laser quenching parameters at time t+1. According to the fitting equation at time t+1 and fixing the laser scanning speed v, the PT control rule is obtained. According to the fitting equation at time t+1 and fixing the laser power density P, the vT control rule is obtained.

[0031] Furthermore, the coating used in the S3 is ANO-2 type. Distilled water needs to be added to the coating before use, and it is heated in a water bath at 47-53°C and stirred for dilution. The coating is applied in layers, with the number of layers being at least two times. Before coating, the small holes on the non-nitrided surface are blocked with asbestos ropes. The drying temperature is 80-100°C, and the drying time is 15-30 minutes.

[0032] Furthermore, the air pressure of the sand blasting in S3 is ≤0.2Mpa, the sand particle size of the sand blasting is 150-200 mesh, the sand is corundum sand, and the roughness of the nitriding area on the surface of the workpiece after the sand blasting treatment is less than or equal to 0.8μm.

[0033] Furthermore, the specific method of gas nitriding treatment of the workpiece is: hang the workpiece in a nitriding furnace, exhaust ammonia into the nitriding furnace until the ammonia decomposition rate in the nitriding furnace is zero, heat the nitriding furnace to 400°C, keep it warm for 1-2 hours, control the nitrogen in the furnace to be stable, then heat the nitriding furnace to 500-530°C and continue to control the nitrogen in the furnace to be stable, keep it warm for 10-50 hours, and then cool it.

[0034] Furthermore, the ammonia decomposition rate during the heat preservation process of the nitriding furnace is 30% to 50%. The cooling treatment method is to pass ammonia and nitrogen into the nitriding furnace and cool it to 80°C, then take the workpiece out of the nitriding furnace and air-cool it to room temperature.

[0035] Furthermore, the method for controlling the stability of nitrogen in the furnace is: obtaining process parameters such as the partial pressure of ammonia and hydrogen in the nitriding furnace, substituting the process parameters into the nitrogen potential value formula Kn=P(NH 3 ) / P(H 2 )^1.5, where Kn is the nitrogen potential value, P(NH 3 ) is the partial pressure of ammonia in the nitriding furnace, P(H 2 ) is the partial pressure of hydrogen in the nitriding furnace. The nitrogen potential value is calculated, and the measured nitrogen potential value is compared with the threshold value set by the process to obtain the deviation value. The flow rate of ammonia and hydrogen entering the nitriding furnace is controlled according to the deviation value.

[0036] Furthermore, the laser quenching treatment device in S3 is a fiber laser with a core diameter of 600um, a wavelength of 1080nm, and a focusing focal length of 400mm. The laser quenching head adopts the integral principle or the DOE diffraction optical principle to shape the light beam, and the output spot size is a rectangular homogenized spot of 100*2mm, 50*2mm, or 15*1.5mm.

[0037] Specific implementation cases;

[0038] Use 95% industrial alcohol to clean the workpiece. After cleaning, use dry compressed air to blow dry. When blowing dry, the flow rate of dry compressed air is 2m / s. Mark the area on the workpiece surface that needs heat treatment;

[0039] The workpiece is scanned in 3D to obtain the surface profile of the heat treatment area, the surface area of ​​the workpiece and the area of ​​the laser quenching area are obtained, the temperature of the laser quenching area of ​​the laser quenching mechanism is adjusted, the quenching parameters corresponding to different quenching temperatures of the device are obtained, the relationship between the temperature of the laser quenching area and the laser quenching parameters is established, and the relationship is fitted using the nonlinear fitting method of the data to obtain the fitting equation Where P is the laser power density quenching, V is the laser scanning speed, T is the quenching temperature, K 1 , K 2 is the fitting coefficient, Wherein θ is the average value of the normal inclination angles at different positions of the laser quenching area of ​​the workpiece;

[0040] The workpiece surface temperature is determined as the laser quenching area temperature T at the initial moment. 0 , using the fitting equation to obtain the fitting equation of laser quenching at time t+1 Where A, B, and C are the coefficients of the laser quenching parameters at time t+1. According to the fitting equation at time t+1 and the fixed laser scanning speed v, the PT control rule is obtained. According to the fitting equation at time t+1 and the fixed laser power density P, the vT control rule is obtained.

[0041] Input the control rules into the controller of the laser quenching device, and put the workpiece into the laser quenching device. The laser quenching device has six working modes, which are:

[0042] 1) The laser quenching treatment device is a fiber laser with a core diameter of 600um, a wavelength of 1080nm, and a focusing focal length of 400mm. The laser quenching head adopts the integral principle to shape the beam and output a rectangular homogenized spot with a spot size of 100*2mm;

[0043] 2) The laser quenching treatment device is a fiber laser with a core diameter of 600um, a wavelength of 1080nm, and a focusing focal length of 400mm. The laser quenching head adopts the integral principle to shape the beam, and the output spot size is 50*2mm;

[0044] 3) The laser quenching treatment device is a fiber laser with a core diameter of 600um, a wavelength of 1080nm, and a focusing focal length of 400mm. The laser quenching head adopts the integral principle to shape the beam and output a rectangular homogenized spot with a spot size of 15*1.5mm;

[0045] 4) The laser quenching treatment device is a fiber laser with a core diameter of 600um, a wavelength of 1080nm, and a focusing focal length of 400mm. The laser quenching head adopts the DOE diffraction optical principle to shape the beam and output a rectangular homogenized spot with a spot size of 100*2mm;

[0046] 5) The laser quenching treatment device is a fiber laser with a core diameter of 600um, a wavelength of 1080nm, and a focusing focal length of 400mm. The laser quenching head adopts the DOE diffraction optical principle to shape the beam, and the output spot size is 50*2mm;

[0047] 6) The laser quenching treatment device is a fiber laser with a core diameter of 600um, a wavelength of 1080nm, and a focusing focal length of 400mm. The laser quenching head adopts the DOE diffraction optical principle to shape the beam and output a rectangular homogenized spot with a spot size of 15*1.5mm;

[0048] The workpiece is taken out after being processed, cooled to room temperature, and the quenched area on the surface of the workpiece is polished to remove the quenching oxide scale;

[0049] The nitriding area on the surface of the workpiece is subjected to sand blasting treatment, the air pressure of the sand blasting is ≤0.2Mpa, the sand particle size of the sand blasting is 150 mesh, the sand is corundum sand, and the roughness of the nitriding area on the surface of the workpiece after the sand blasting treatment is less than or equal to 0.8μm;

[0050] Add distilled water to the ANO-2 type coating, heat it in a water bath at 47°C and stir to dilute it, use asbestos rope to plug the small holes in the non-nitriding area on the surface of the workpiece, and use the diluted coating to protect the non-nitriding area on the surface of the workpiece by layered coating. The number of layers is two. After coating, the workpiece is dried at a temperature of 100°C and a drying time of 15 minutes.

[0051] The workpiece is suspended in the nitriding furnace, and ammonia is exhausted into the nitriding furnace until the ammonia decomposition rate in the nitriding furnace is zero. The temperature in the nitriding furnace is raised to 400°C, and kept warm for 1-2 hours. Then the temperature in the nitriding furnace is raised to 500°C, and the process parameters such as the partial pressure of ammonia and hydrogen in the nitriding furnace are obtained. The process parameters are substituted into the nitrogen potential value formula Kn=P(NH 3 ) / P(H 2 )^1.5, where Kn is the nitrogen potential value, P(NH 3 ) is the partial pressure of ammonia in the nitriding furnace, P(H 2 ) is the partial pressure of hydrogen in the nitriding furnace, the nitrogen potential value is calculated, the measured nitrogen potential value is compared with the threshold value set by the process, and the deviation value is obtained. The flow rate of ammonia and hydrogen entering the nitriding furnace is controlled according to the deviation value to control the stability of nitrogen in the furnace. After keeping warm for 10 hours, ammonia and nitrogen are passed into the nitriding furnace and cooled to 80°C, and then the workpiece is taken out of the nitriding furnace and air-cooled to room temperature. After cooling, the workpiece is cleaned and packaged for shipment.

[0052] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A special heat treatment process for improving the wear resistance of a workpiece, characterized in that: The steps include: S1, cleaning the workpiece, drying it with dry compressed air, and marking the area on the surface of the workpiece that needs heat treatment; S2, performing 3D scanning on the workpiece to obtain the surface profile of the heat treatment area, obtaining the surface area of ​​the workpiece and the area data of the laser quenching area, establishing a fitting equation between the laser quenching parameter and the temperature of the heat treatment area, determining the control rule of the laser quenching parameter with the temperature of the laser quenching area according to the established fitting equation, inputting the control rule into the controller of the laser quenching device, placing the workpiece into the laser quenching device, and the laser quenching device performing laser quenching treatment on the workpiece; S3, taking out the workpiece after treatment, cooling it to room temperature, polishing the quenched area on the workpiece surface to remove the quenching oxide scale, sandblasting the nitrided area on the workpiece surface, adjusting the surface roughness of the nitrided area on the workpiece surface, and then coating the non-nitrided area on the workpiece surface for protection. After drying, the treated workpiece is placed in a nitriding furnace and subjected to gas nitriding treatment. After the treatment is completed, the workpiece is taken out and cleaned, and then packaged and shipped.

2. A special heat treatment process for improving the wear resistance of a workpiece according to claim 1, characterized in that: The cleaning agent used for cleaning the workpiece in S1 is industrial alcohol or metal cleaning agent, and the percentage concentration of industrial alcohol is 95%-97%. The flow rate of dry compressed air when drying the workpiece is 2-3.12m / s.

3. A special heat treatment process for improving the wear resistance of a workpiece according to claim 1, characterized in that: The specific method of establishing the fitting equation between the laser quenching parameters and the temperature of the heat treatment area in S2 is: adjusting the temperature of the laser quenching area of ​​the laser quenching mechanism, obtaining the quenching parameters corresponding to different quenching temperatures of the device, establishing the relationship between the temperature of the laser quenching area and the laser quenching parameters, and fitting the relationship using a nonlinear fitting method of data to obtain a fitting equation Where P is the laser power density quenching, V is the laser scanning speed, T is the quenching temperature, K1 and K2 are fitting coefficients, Wherein θ is the average value of the normal inclination angles at different positions of the laser quenching area of ​​the workpiece.

4. A special heat treatment process for improving the wear resistance of a workpiece according to claim 1, characterized in that: The specific method for determining the control rule of the laser quenching parameters with the laser quenching area temperature according to the established fitting equation in S2 is: the surface temperature of the workpiece is determined as the laser quenching area temperature T0 at the initial moment, and the fitting equation for laser quenching at time t+1 is obtained by using the fitting equation Among them, A, B, and C are the coefficients of laser quenching parameters at time t+1. According to the fitting equation at time t+1 and fixing the laser scanning speed v, the PT control rule is obtained. According to the fitting equation at time t+1 and fixing the laser power density P, the vT control rule is obtained.

5. A special heat treatment process for improving the wear resistance of a workpiece according to claim 1, characterized in that: The coating used in the S3 is ANO-2 type. Distilled water needs to be added to the coating before use, and it needs to be heated in a water bath at 47-53°C and stirred for dilution. The coating is applied in layers, with the number of layers being at least two times. Before coating, the small holes on the non-nitrided surface are blocked with asbestos ropes. The drying temperature is 80-100°C, and the drying time is 15-30 minutes.

6. A special heat treatment process for improving the wear resistance of a workpiece according to claim 1, characterized in that: The air pressure of the sand blasting in S3 is ≤0.2Mpa, the sand particle size of the sand blasting is 150-200 mesh, the sand is corundum sand, and the roughness of the nitriding area on the surface of the workpiece after the sand blasting treatment is less than or equal to 0.8μm.

7. A special heat treatment process for improving the wear resistance of a workpiece according to claim 1, characterized in that: The specific method of gas nitriding treatment of the workpiece is: hanging the workpiece in a nitriding furnace, exhausting ammonia into the nitriding furnace until the ammonia decomposition rate in the nitriding furnace is zero, heating the nitriding furnace to 400°C, keeping it warm for 1-2 hours, controlling the nitrogen in the furnace to be stable, then heating the nitriding furnace to 500-530°C and continuing to control the nitrogen in the furnace to be stable, keeping it warm for 10-50 hours, and then cooling it.

8. A special heat treatment process for improving the wear resistance of a workpiece according to claim 7, characterized in that: The ammonia decomposition rate during the heat preservation process of the nitriding furnace is 30% to 50%. The cooling treatment method is to pass ammonia and nitrogen into the nitriding furnace and cool it to 80° C., then take the workpiece out of the nitriding furnace and air-cool it to room temperature.

9. A special heat treatment process for improving the wear resistance of a workpiece according to claim 7, characterized in that: The method for controlling the stability of nitrogen in the furnace is as follows: obtaining process parameters such as the partial pressure of ammonia and hydrogen in the nitriding furnace, substituting the process parameters into a nitrogen potential value formula Kn=P(NH3) / P(H2)^1.5, wherein Kn is the nitrogen potential value, P(NH3) is the partial pressure of ammonia in the nitriding furnace, and P(H2) is the partial pressure of hydrogen in the nitriding furnace, calculating the nitrogen potential value, comparing the measured nitrogen potential value with a threshold value set by the process, obtaining a deviation value, and controlling the flow of ammonia and hydrogen entering the nitriding furnace according to the deviation value.

10. A special heat treatment process for improving the wear resistance of a workpiece according to claim 1, characterized in that: The laser quenching treatment device in S3 is a fiber laser with a core diameter of 600um, a wavelength of 1080nm, and a focusing focal length of 400mm. The laser quenching head uses the integral principle or the DOE diffraction optical principle to shape the light beam and output a rectangular homogenized light spot with a spot size of 100*2mm, 50*2mm, or 15*1.5mm.

Images