CN111534785A - Surface hardening treatment method for metal stamping die - Google Patents
Surface hardening treatment method for metal stamping die Download PDFInfo
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- CN111534785A CN111534785A CN202010384490.5A CN202010384490A CN111534785A CN 111534785 A CN111534785 A CN 111534785A CN 202010384490 A CN202010384490 A CN 202010384490A CN 111534785 A CN111534785 A CN 111534785A
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/24—Nitriding
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/02—Pretreatment of the material to be coated
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/40—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions
- C23C8/42—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions only one element being applied
- C23C8/48—Nitriding
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/60—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes
- C23C8/62—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes only one element being applied
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/80—After-treatment
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- Organic Chemistry (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
The invention discloses a surface hardening treatment method for a metal stamping die, which comprises the steps of primary inspection, front polishing, surface nitriding, secondary polishing, coating, rear polishing and finished product inspection. The invention can improve the surface wear resistance of the metal stamping die, so that the hardness of the metal stamping die is higher, and the service life of the metal stamping die is greatly prolonged; the friction coefficient is low, so that the lubricating property is good, and the processing stress is reduced; the chemical corrosion resistance of the metal die is greatly improved; the processing quality can be improved, the galling and strain of products can be prevented, the product quality is improved, and the cost is reduced; the frequency of maintenance is reduced, the trouble of repeated mould unloading, polishing and re-mould loading is saved, and the efficiency is improved.
Description
Technical Field
The invention belongs to the technical field of surface treatment of dies, and particularly relates to a surface hardening treatment method for a metal stamping die.
Background
The stamping die is a special process equipment for processing materials (metal or nonmetal) into parts (or semi-finished products) in cold stamping processing, and is called a cold stamping die (commonly called a cold stamping die). Stamping is a press working method in which a die mounted on a press is used to apply pressure to a material at room temperature to cause separation or plastic deformation of the material, thereby obtaining a desired part.
The material for making the stamping die comprises steel, hard alloy, steel bonded hard alloy, zinc-based alloy, low-melting point alloy, aluminum bronze, high polymer material and the like. The material for manufacturing the stamping die is mainly made of steel, and the types of the commonly used die working part materials are as follows: carbon tool steel, low alloy tool steel, high carbon high chromium or medium chromium tool steel, medium carbon alloy steel, high speed steel, base steel, and cemented carbide, steel bonded cemented carbide, and the like.
Although the metal stamping die has certain hardness and wear resistance, after the metal stamping die is used for a long time, the wear resistance and the hardness of the metal stamping die can be influenced, so that the friction coefficient can be increased, the lubricity is poor, the processing stress is increased, the service life of the die is seriously influenced, the quality of a product can be influenced, galling and galling of the product are caused, in addition, the maintenance frequency can be increased, the die is frequently required to be disassembled and polished and then assembled, and the production and processing efficiency is influenced.
Therefore, in view of the above technical problems, it is necessary to provide a surface hardening treatment method for a metal press mold.
Disclosure of Invention
The present invention is directed to a surface hardening treatment method for a metal stamping die to solve the above problems.
In order to achieve the above object, an embodiment of the present invention provides the following technical solutions:
a surface hardening treatment method for a metal stamping die comprises the following steps:
s1, preliminary examination
Preliminarily checking whether the metal stamping die required to be treated meets the requirements of surface hardening treatment;
s2, pre-polishing
Polishing the surface of the metal die meeting the requirements of the preliminary inspection, and removing foreign matters and/or impurities adhered to the surface of the metal die;
s3 surface nitriding
Nitriding the surface of the metal die;
s4, secondary polishing
Polishing the metal mould subjected to nitriding treatment for the second time to ensure the smoothness of the surface of the metal mould;
s5 coating
Processing the surface of the metal die by adopting a PVD coating process to form a hardened coating on the surface of the metal die;
s6, post-polishing
Polishing the metal mold after S5 to remove redundant coating materials;
s7, inspection of finished products
And (4) checking whether the hardened metal mold is qualified or not, finishing the hardening treatment when the hardened metal mold is qualified, and returning to S4 and sequentially carrying out the treatments of S4, S5, S6 and S7 when the hardened metal mold is unqualified.
In one embodiment, the types of materials of the metal stamping die include die steel, structural steel with carbon content greater than 0.3%, cast iron, and cemented carbide.
In one embodiment, in S5, the hardened coating has a composition of one or more of TiN, TiC, TiCN, ZrN, CrN, MoS2, TiAlN, TiAlCN, TiN-AlN, CNx, DLC and ta-C.
In one embodiment, the thickness of the hardened coating is 1 to 6 microns.
In one embodiment, the hardened coating has a thickness of 3 microns.
In one embodiment, in S5, the duration of the coating step is 2 to 6 hours.
In one embodiment, between S6 and S7, S61 is further included,
and S61, coating a polytetrafluoroethylene coating on the surface of the die hardened coating treated in the S6.
In one embodiment, the polytetrafluoroethylene coating has a thickness of 20 to 40 μm.
In one embodiment, the polytetrafluoroethylene coating has a thickness of 30 microns.
In one embodiment, the step S3 includes the following sub-steps:
s31, deoiling the surface of the metal mold in the S2 by using a gas deoiling method;
s32, placing the metal die processed in the S31 into a nitriding furnace, sealing a furnace cover, heating, and removing air in the furnace before heating to 150 ℃;
s33, keeping the treatment temperature in the nitriding furnace at 480-560 ℃ for 4-10 hours;
s34, rapidly cooling and nitriding furnace and metal mold.
Compared with the prior art, the invention has the following advantages:
the invention can improve the surface wear resistance of the metal stamping die, so that the hardness of the metal stamping die is higher, and the service life of the metal stamping die is greatly prolonged; the friction coefficient is low, so that the lubricating property is good, and the processing stress is reduced; the chemical corrosion resistance of the metal die is greatly improved; the processing quality can be improved, the galling and strain of products can be prevented, the product quality is improved, and the cost is reduced; the frequency of maintenance is reduced, the trouble of repeated mould unloading, polishing and re-mould loading is saved, and the efficiency is improved.
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, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of a case hardening treatment method for a metal stamping die according to an embodiment of the present invention;
fig. 2 is a data diagram of an experiment of using effect of a surface hardening treatment method for a metal stamping die according to an embodiment of the present invention.
Detailed Description
The present invention will be described in detail below with reference to embodiments shown in the drawings. The embodiments are not intended to limit the present invention, and structural, methodological, or functional changes made by those skilled in the art according to the embodiments are included in the scope of the present invention.
Example 1:
the invention discloses a surface hardening treatment method for a metal stamping die, which comprises the following steps of:
s1, preliminary examination
Preliminarily checking whether the metal stamping die required to be treated meets the requirements of surface hardening treatment;
wherein the material types of the metal stamping die comprise die steel, structural steel with carbon content more than 0.3%, cast iron and hard alloy.
S2, pre-polishing
Polishing the surface of the metal die meeting the requirements of the preliminary inspection, and removing foreign matters and/or impurities adhered to the surface of the metal die;
s3 surface nitriding
The surface of the metal die is subjected to nitriding treatment, and the method further comprises the following steps:
s31, deoiling the surface of the metal mold in the S2 by using a gas deoiling method;
s32, placing the metal die processed in the S31 into a nitriding furnace, sealing a furnace cover, heating, and removing air in the furnace before heating to 150 ℃;
the main functions of the exhaust furnace are to prevent the ammonia gas from contacting with air during decomposition to generate explosive gas, and to prevent the surface oxidation of the treated object and the support. The used gas includes ammonia gas and nitrogen gas.
S33, keeping the treatment temperature in the nitriding furnace at 520 ℃ for 7 hours;
s34, rapidly cooling and nitriding furnace and metal mold.
Most industrial nitriding furnaces are equipped with heat exchangers for rapidly cooling the furnace and the parts to be treated after the nitriding operation is completed. Namely, after nitriding is finished, the heating power supply is turned off, the furnace temperature is reduced by about 50 ℃, and then the heat exchanger is started after the flow of ammonia is doubled. At this time, it is necessary to observe whether bubbles are overflowed from the glass bottle connected to the exhaust pipe to confirm the positive pressure in the furnace. After the ammonia gas introduced into the furnace is stabilized, the flow rate of ammonia can be reduced until the positive pressure in the furnace is maintained. When the furnace temperature is decreased to 150 ℃ or below, the furnace cover can be opened after introducing air or nitrogen gas, i.e., by removing the gas in the furnace as described above.
The nitriding treatment refers to a chemical heat treatment process for making nitrogen atoms penetrate into the surface layer of a workpiece in a certain medium at a certain temperature. The metal die subjected to nitriding treatment has the characteristics of excellent wear resistance, fatigue resistance, corrosion resistance and high temperature resistance.
S4, secondary polishing
Polishing the metal mould subjected to nitriding treatment for the second time to ensure the smoothness of the surface of the metal mould;
s5 coating
Processing the surface of the metal die by adopting a PVD coating process to form a hardened coating on the surface of the metal die;
the hardening coating comprises one or more of TiN, TiC, TiCN, ZrN, CrN, MoS2, TiAlN, TiAlCN, TiN-AlN, CNx, DLC and ta-C.
The duration of the coating step was 4 hours and the thickness of the hardened coating was 3 microns.
S6, post-polishing
Polishing the metal mold after S5 to remove redundant coating materials;
and S61, coating a polytetrafluoroethylene coating on the surface of the die hardened coating treated in the S6.
Specifically, the thickness of the polytetrafluoroethylene coating was 30 microns.
The metal die coated with polytetrafluoroethylene has the following characteristics: 1. non-stick property: almost all of the material did not adhere to the teflon coating film. Very thin films also exhibit good non-stick properties. 2. Heat resistance: the teflon coating film has excellent heat-resistant and low-temperature-resistant characteristics. Can resist high temperature to 300 ℃ in a short time, can be continuously used at the temperature of 240-260 ℃, has obvious thermal stability, can work at a freezing temperature without embrittlement and can not melt at a high temperature. 3. Sliding property: the teflon coating film has a low friction coefficient. The coefficient of friction varies during load sliding, but only between 0.05 and 0.15. 4. Moisture resistance: the teflon coating surface is not stained with water and oil, and is not easy to be stained with solution during production operation, if a small amount of dirt is adhered, the teflon coating can be removed by simply wiping. The machine has short stop time, saves working hours and can improve the working efficiency. 5. Abrasion resistance: under high load, the wear-resisting property is excellent. Under a certain load, the wear-resistant and non-adhesive dual-purpose wear-resistant rubber belt has the advantages of wear resistance and non-adhesion. 6. Corrosion resistance: teflon is hardly attacked by chemicals and can protect parts from any kind of chemical attack.
S7, inspection of finished products
And (4) checking whether the hardened metal mold is qualified or not, finishing the hardening treatment when the hardened metal mold is qualified, and returning to S4 and sequentially carrying out the treatments of S4, S5, S6 and S7 when the hardened metal mold is unqualified.
Example 2:
the invention discloses a surface hardening treatment method for a metal stamping die, which comprises the following steps of:
s1, preliminary examination
Preliminarily checking whether the metal stamping die required to be treated meets the requirements of surface hardening treatment;
wherein the material types of the metal stamping die comprise die steel, structural steel with carbon content more than 0.3%, cast iron and hard alloy.
S2, pre-polishing
Polishing the surface of the metal die meeting the requirements of the preliminary inspection, and removing foreign matters and/or impurities adhered to the surface of the metal die;
s3 surface nitriding
The surface of the metal die is subjected to nitriding treatment, and the method further comprises the following steps:
s31, deoiling the surface of the metal mold in the S2 by using a gas deoiling method;
s32, placing the metal die processed in the S31 into a nitriding furnace, sealing a furnace cover, heating, and removing air in the furnace before heating to 150 ℃;
the main functions of the exhaust furnace are to prevent the ammonia gas from contacting with air during decomposition to generate explosive gas, and to prevent the surface oxidation of the treated object and the support. The used gas includes ammonia gas and nitrogen gas.
S33, keeping the treatment temperature in the nitriding furnace at 480 ℃ for 4 hours;
s34, rapidly cooling and nitriding furnace and metal mold.
Most industrial nitriding furnaces are equipped with heat exchangers for rapidly cooling the furnace and the parts to be treated after the nitriding operation is completed. Namely, after nitriding is finished, the heating power supply is turned off, the furnace temperature is reduced by about 50 ℃, and then the heat exchanger is started after the flow of ammonia is doubled. At this time, it is necessary to observe whether bubbles are overflowed from the glass bottle connected to the exhaust pipe to confirm the positive pressure in the furnace. After the ammonia gas introduced into the furnace is stabilized, the flow rate of ammonia can be reduced until the positive pressure in the furnace is maintained. When the furnace temperature is decreased to 150 ℃ or below, the furnace cover can be opened after introducing air or nitrogen gas, i.e., by removing the gas in the furnace as described above.
The nitriding treatment refers to a chemical heat treatment process for making nitrogen atoms penetrate into the surface layer of a workpiece in a certain medium at a certain temperature. The metal die subjected to nitriding treatment has the characteristics of excellent wear resistance, fatigue resistance, corrosion resistance and high temperature resistance.
S4, secondary polishing
Polishing the metal mould subjected to nitriding treatment for the second time to ensure the smoothness of the surface of the metal mould;
s5 coating
Processing the surface of the metal die by adopting a PVD coating process to form a hardened coating on the surface of the metal die;
the hardening coating comprises one or more of TiN, TiC, TiCN, ZrN, CrN, MoS2, TiAlN, TiAlCN, TiN-AlN, CNx, DLC and ta-C.
The duration of the coating step was 2 hours.
Specifically, the thickness of the hardened coating was 1 micron.
S6, post-polishing
Polishing the metal mold after S5 to remove redundant coating materials;
and S61, coating a polytetrafluoroethylene coating on the surface of the die hardened coating treated in the S6.
Specifically, the thickness of the polytetrafluoroethylene coating was 20 microns.
The metal die coated with polytetrafluoroethylene has the following characteristics: 1. non-stick property: almost all of the material did not adhere to the teflon coating film. Very thin films also exhibit good non-stick properties. 2. Heat resistance: the teflon coating film has excellent heat-resistant and low-temperature-resistant characteristics. Can resist high temperature to 300 ℃ in a short time, can be continuously used at the temperature of 240-260 ℃, has obvious thermal stability, can work at a freezing temperature without embrittlement and can not melt at a high temperature. 3. Sliding property: the teflon coating film has a low friction coefficient. The coefficient of friction varies during load sliding, but only between 0.05 and 0.15. 4. Moisture resistance: the teflon coating surface is not stained with water and oil, and is not easy to be stained with solution during production operation, if a small amount of dirt is adhered, the teflon coating can be removed by simply wiping. The machine has short stop time, saves working hours and can improve the working efficiency. 5. Abrasion resistance: under high load, the wear-resisting property is excellent. Under a certain load, the wear-resistant and non-adhesive dual-purpose wear-resistant rubber belt has the advantages of wear resistance and non-adhesion. 6. Corrosion resistance: teflon is hardly attacked by chemicals and can protect parts from any kind of chemical attack.
S7, inspection of finished products
And (4) checking whether the hardened metal mold is qualified or not, finishing the hardening treatment when the hardened metal mold is qualified, and returning to S4 and sequentially carrying out the treatments of S4, S5, S6 and S7 when the hardened metal mold is unqualified.
Example 3:
the invention discloses a surface hardening treatment method for a metal stamping die, which comprises the following steps of:
s1, preliminary examination
Preliminarily checking whether the metal stamping die required to be treated meets the requirements of surface hardening treatment;
wherein the material types of the metal stamping die comprise die steel, structural steel with carbon content more than 0.3%, cast iron and hard alloy.
S2, pre-polishing
Polishing the surface of the metal die meeting the requirements of the preliminary inspection, and removing foreign matters and/or impurities adhered to the surface of the metal die;
s3 surface nitriding
The surface of the metal die is subjected to nitriding treatment, and the method further comprises the following steps:
s31, deoiling the surface of the metal mold in the S2 by using a gas deoiling method;
s32, placing the metal die processed in the S31 into a nitriding furnace, sealing a furnace cover, heating, and removing air in the furnace before heating to 150 ℃;
the main functions of the exhaust furnace are to prevent the ammonia gas from contacting with air during decomposition to generate explosive gas, and to prevent the surface oxidation of the treated object and the support. The used gas includes ammonia gas and nitrogen gas.
S33, keeping the treatment temperature in the nitriding furnace at 560 ℃ for 10 hours;
s34, rapidly cooling and nitriding furnace and metal mold.
Most industrial nitriding furnaces are equipped with heat exchangers for rapidly cooling the furnace and the parts to be treated after the nitriding operation is completed. Namely, after nitriding is finished, the heating power supply is turned off, the furnace temperature is reduced by about 50 ℃, and then the heat exchanger is started after the flow of ammonia is doubled. At this time, it is necessary to observe whether bubbles are overflowed from the glass bottle connected to the exhaust pipe to confirm the positive pressure in the furnace. After the ammonia gas introduced into the furnace is stabilized, the flow rate of ammonia can be reduced until the positive pressure in the furnace is maintained. When the furnace temperature is decreased to 150 ℃ or below, the furnace cover can be opened after introducing air or nitrogen gas, i.e., by removing the gas in the furnace as described above.
The nitriding treatment refers to a chemical heat treatment process for making nitrogen atoms penetrate into the surface layer of a workpiece in a certain medium at a certain temperature. The metal die subjected to nitriding treatment has the characteristics of excellent wear resistance, fatigue resistance, corrosion resistance and high temperature resistance.
S4, secondary polishing
Polishing the metal mould subjected to nitriding treatment for the second time to ensure the smoothness of the surface of the metal mould;
s5 coating
Processing the surface of the metal die by adopting a PVD coating process to form a hardened coating on the surface of the metal die;
the hardening coating comprises one or more of TiN, TiC, TiCN, ZrN, CrN, MoS2, TiAlN, TiAlCN, TiN-AlN, CNx, DLC and ta-C.
The duration of the coating step was 6 hours.
Specifically, the thickness of the hardened coating was 6 microns.
S6, post-polishing
Polishing the metal mold after S5 to remove redundant coating materials;
and S61, coating a polytetrafluoroethylene coating on the surface of the die hardened coating treated in the S6.
Specifically, the polytetrafluoroethylene coating has a thickness of 40 microns.
The metal die coated with polytetrafluoroethylene has the following characteristics: 1. non-stick property: almost all of the material did not adhere to the teflon coating film. Very thin films also exhibit good non-stick properties. 2. Heat resistance: the teflon coating film has excellent heat-resistant and low-temperature-resistant characteristics. Can resist high temperature to 300 ℃ in a short time, can be continuously used at the temperature of 240-260 ℃, has obvious thermal stability, can work at a freezing temperature without embrittlement and can not melt at a high temperature. 3. Sliding property: the teflon coating film has a low friction coefficient. The coefficient of friction varies during load sliding, but only between 0.05 and 0.15. 4. Moisture resistance: the teflon coating surface is not stained with water and oil, and is not easy to be stained with solution during production operation, if a small amount of dirt is adhered, the teflon coating can be removed by simply wiping. The machine has short stop time, saves working hours and can improve the working efficiency. 5. Abrasion resistance: under high load, the wear-resisting property is excellent. Under a certain load, the wear-resistant and non-adhesive dual-purpose wear-resistant rubber belt has the advantages of wear resistance and non-adhesion. 6. Corrosion resistance: teflon is hardly attacked by chemicals and can protect parts from any kind of chemical attack.
S7, inspection of finished products
And (4) checking whether the hardened metal mold is qualified or not, finishing the hardening treatment when the hardened metal mold is qualified, and returning to S4 and sequentially carrying out the treatments of S4, S5, S6 and S7 when the hardened metal mold is unqualified.
Referring to fig. 2, the effect of the above 3 embodiments in different molds is shown, wherein the average value is rounded.
According to the technical scheme, the invention has the following beneficial effects:
the invention can improve the surface wear resistance of the metal stamping die, so that the hardness of the metal stamping die is higher, and the service life of the metal stamping die is greatly prolonged; the friction coefficient is low, so that the lubricating property is good, and the processing stress is reduced; the chemical corrosion resistance of the metal die is greatly improved; the processing quality can be improved, the galling and strain of products can be prevented, the product quality is improved, and the cost is reduced; the frequency of maintenance is reduced, the trouble of repeated mould unloading, polishing and re-mould loading is saved, and the efficiency is improved.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (10)
1. A surface hardening treatment method for a metal stamping die is characterized by comprising the following steps:
s1, preliminary examination
Preliminarily checking whether the metal stamping die required to be treated meets the requirements of surface hardening treatment;
s2, pre-polishing
Polishing the surface of the metal die meeting the requirements of the preliminary inspection, and removing foreign matters and/or impurities adhered to the surface of the metal die;
s3 surface nitriding
Nitriding the surface of the metal die;
s4, secondary polishing
Polishing the metal mould subjected to nitriding treatment for the second time to ensure the smoothness of the surface of the metal mould;
s5 coating
Processing the surface of the metal die by adopting a PVD coating process to form a hardened coating on the surface of the metal die;
s6, post-polishing
Polishing the metal mold after S5 to remove redundant coating materials;
s7, inspection of finished products
And (4) checking whether the hardened metal mold is qualified or not, finishing the hardening treatment when the hardened metal mold is qualified, and returning to S4 and sequentially carrying out the treatments of S4, S5, S6 and S7 when the hardened metal mold is unqualified.
2. The method of claim 1, wherein the types of materials for the metal stamping die include die steel, structural steel containing more than 0.3% carbon, cast iron, and cemented carbide.
3. The method of claim 1, wherein in S5, the hardening coating comprises one or more of TiN, TiC, TiCN, ZrN, CrN, MoS2, TiAlN, TiAlCN, TiN-AlN, CNx, DLC, and ta-C.
4. The method of claim 1, wherein the hardened coating has a thickness of 1 to 6 microns.
5. The method of claim 4, wherein the hardened coating has a thickness of 3 microns.
6. The method of claim 1, wherein the coating step is performed for 2 to 6 hours in S5.
7. The method of claim 1, further comprising S61 between S6 and S7,
and S61, coating a polytetrafluoroethylene coating on the surface of the die hardened coating treated in the S6.
8. The method of claim 7, wherein the polytetrafluoroethylene coating has a thickness of 20 to 40 μm.
9. The method of claim 1, wherein the polytetrafluoroethylene coating has a thickness of 30 microns.
10. The method of claim 1, wherein the step S3 includes the following sub-steps:
s31, deoiling the surface of the metal mold in the S2 by using a gas deoiling method;
s32, placing the metal die processed in the S31 into a nitriding furnace, sealing a furnace cover, heating, and removing air in the furnace before heating to 150 ℃;
s33, keeping the treatment temperature in the nitriding furnace at 480-560 ℃ for 4-10 hours;
s34, rapidly cooling and nitriding furnace and metal mold.
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| CN114749356A (en) * | 2022-04-14 | 2022-07-15 | 重庆红江机械有限责任公司 | Preparation method of steel piece surface anti-drop DLC coating |
| CN114807833A (en) * | 2022-04-20 | 2022-07-29 | 西安致远航空科技有限公司 | Metal mold surface treatment process |
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| CN102877070A (en) * | 2012-06-14 | 2013-01-16 | 浙江吉利汽车研究院有限公司杭州分公司 | Surface compound treatment method for steel mould |
| CN108893707A (en) * | 2018-07-23 | 2018-11-27 | 江苏苏德涂层有限公司 | Aluminium die casting surface coated treatment technique and the cated aluminium die casting of tool |
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| CN101269558A (en) * | 2008-04-03 | 2008-09-24 | 友达光电股份有限公司 | Structure having high mould-release property |
| CN102877070A (en) * | 2012-06-14 | 2013-01-16 | 浙江吉利汽车研究院有限公司杭州分公司 | Surface compound treatment method for steel mould |
| CN108893707A (en) * | 2018-07-23 | 2018-11-27 | 江苏苏德涂层有限公司 | Aluminium die casting surface coated treatment technique and the cated aluminium die casting of tool |
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