Steel part surface sulfurizing process

Abstract

The invention discloses a steel part surface sulfurizing process which comprises the following steps: uniformly mixing an anti-friction coating material, adding a binder, and uniformly mixing again to form a pasty coating A; the antifriction coating material comprises iron powder, sulfur powder, molybdenum disulfide powder and nickel-60 powder; mixing a protective layer material with a binder to form a pasty coating B; the protective layer is made of titanium dioxide; cleaning the surface of the steel part and roughening the surface of the steel part; the coating A is coated on the surface of the steel part to form an antifriction coating, and then the coating B is coated to form a protective layer; and the surface of the steel part is heated until the anti-friction coating with the sulfide is formed, and then pressure is applied to press the coating material on the steel part. According to the steel part surface sulfurizing process, an antifriction coating with good mechanical and tribological characteristics can be formed on the surface of the steel part.

Description

Technical Field

[0001] The invention belongs to the technical field of steel surface treatment and relates to a steel surface sulfurization process. Background Art

[0002] The metal surface vulcanization treatment mainly forms a layer of sulfide on the metal surface to enhance the metal's fatigue strength, corrosion resistance and surface hardness. Specifically, after the vulcanization treatment, the metal surface hardness can be increased by more than 2 times, the fatigue strength can be increased to 3-5 times the original, and the corrosion resistance can also be greatly improved. These superior properties make the metal more stable and reliable during use.

[0003] The surface vulcanization of metals is mainly achieved through chemical reactions and physical changes. First, the chemical reaction is the adsorption of sulfur on the steel surface to form sulfides, which is the main mechanism of action. In addition, the sulfide film can also provide a protective film for the steel surface, reducing the risk of rust and playing an anti-corrosion role. Secondly, the physical change is due to the formation of extremely strong chemical bonds by sulfur on the steel surface, thereby increasing the hardness and wear resistance of the steel surface, and thus enhancing the fatigue resistance of the steel.

[0004] Common metal surface sulfidation treatment methods mainly include chemical sulfidation, sulfurization, oxidative sulfidation, etc. Among them, the chemical sulfidation method is to immerse the metal in a thiocyanate solution to form a layer of sulfide on the metal surface. The sulfurization method is to place the metal part in a container with sulfurized hydrogen gas to form sulfide on the metal surface. The oxidative sulfidation method is to partially oxidize metals such as copper, zinc, and silver and generate them in a sulfide film.

[0005] The application field of metal surface vulcanization treatment is very wide, and it can be used in various fields such as aerospace, manufacturing, automobiles, electronics, electrical appliances, medical equipment, etc. Especially in some application environments with harsh conditions, metal surface vulcanization treatment can better reflect its effectiveness and superiority. Summary of the invention

[0006] Purpose of the invention: The purpose of the invention is to provide a steel surface sulfurization process.

[0007] Technical solution: A steel surface sulfurization process of the present invention comprises the following steps:

[0008] (1) mixing the anti-friction coating material uniformly, adding a binder and mixing again uniformly to form a paste coating A; the anti-friction coating material comprises iron powder, sulfur powder, molybdenum disulfide powder, and nickel 60 powder;

[0009] (2) mixing a protective layer material and a binder into a paste-like coating B; the protective layer material is titanium dioxide;

[0010] (3) Clean the surface of the steel parts and roughen the surface of the steel parts;

[0011] (4) coating A is applied to the surface of the steel part to form a friction-reducing coating, and then coating B is applied to form a protective layer;

[0012] (5) The surface of the steel part is heated to form a friction-reducing coating having sulfide, and then pressure is applied to press the coating material onto the steel part.

[0013] Furthermore, the mass components of the anti-friction coating material are: 30-40% iron powder, 20-30% sulfur powder, 10-20% molybdenum disulfide powder, and 10-20% nickel 60 powder.

[0014] Furthermore, the binder is a phosphate inorganic binder.

[0015] Furthermore, the mass percentage of the binder in the coating A is 5-20%.

[0016] Furthermore, the mass percentage of the binder in the coating B is 5-20%.

[0017] Furthermore, the step (3) includes removing oil stains on the surface of the steel part by pickling and alkali neutralization, and roughening the surface of the steel part by using a steel brush.

[0018] Furthermore, in step (4), the thickness of the anti-friction coating is 0.1-0.2 mm.

[0019] Furthermore, in step (4), the thickness of the protective layer is 0.3-0.5 mm.

[0020] Furthermore, in step (5), the heating temperature is maintained at 800-1000° C. for 5-20 seconds.

[0021] Furthermore, the heating method of step (5) is induction heating.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: 1. The present invention utilizes the reaction Fe+S==FeS between iron and sulfur to form sulfides with anti-friction effect, and absorbs a large amount of heat generated by the reaction between iron and sulfur by adding molybdenum disulfide powder and nickel 60 powder to the anti-friction coating material, while reducing the amount of iron powder and sulfur powder to control the heat release. At the same time, molybdenum disulfide itself has a good anti-friction effect, and nickel 60 powder improves wettability with the base steel after being heated to increase the bonding strength.

[0023] 2. The present invention uses titanium dioxide as a material and applies it on the outside of the anti-friction coating to form a protective layer. The titanium dioxide protective layer can prevent the loss of released heat, maintain the high temperature at the interface between the coating and the substrate steel, and promote the diffusion of elements in the coating; in addition, it prevents the gradual oxidation of ferrous sulfide into ferrosoferric oxide and sulfur, and prevents the occurrence of the reaction 3FeS+2O2=3S+Fe3O4, which reduces the coating effect.

[0024] 3. The present invention uses a phosphate inorganic binder. When the coating is heated and cured, the metal crystal vibration causes the atoms of the metal substrate and the inorganic binder coating to diffuse, forming a diffuse solid solution interface between the metal and non-metal atoms. The solid solution interface can enhance the bonding strength between the substrate and the coating. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below in conjunction with different embodiments.

[0026] A steel surface sulfurization process in this embodiment, the process implementation process is:

[0027] (1) Iron powder, sulfur powder, molybdenum disulfide powder, and nickel 60 powder are mixed uniformly according to a predetermined ratio, and a binder is added and mixed uniformly again to form a paste coating A;

[0028] (2) Adding a binder to the titanium dioxide material to form a paste-like coating B;

[0029] (3) Clean the surface of steel parts by pickling and alkali neutralization to remove surface oil stains, etc., and use a steel brush to roughen the surface of steel parts;

[0030] (4) coating the coating A on the surface of the steel part by spraying or other methods to form a friction-reducing coating with a thickness of 0.3-0.5 mm; then coating the coating B to form a protective layer with a thickness of 0.1-0.2 mm;

[0031] (5) Heat the surface of the steel part to 800-1000℃ and maintain for 5-20 seconds to form a friction-reducing coating with sulfide, and then press the coating material onto the steel part. Since the reaction of iron powder and sulfur powder needs to be completed under high temperature conditions, induction heating is used to induce the reaction between iron and sulfur. The pressure can be applied by using a ceramic fixture or roller to press the coating material onto the steel part, thereby obtaining a stronger bonding strength.

[0032] The mass percentage of the coating material is: 30-40% iron powder, 20-30% sulfur powder, 10-20% molybdenum disulfide powder, and 10-20% nickel 60 powder. The protective layer material is titanium dioxide. The binder is a phosphate inorganic binder, and the mass percentage of the binder in the coating A and the coating B is 5-20%.

[0033] Example 1

[0034] (1) The friction-reducing coating materials of the following mass components are mixed uniformly: 40% iron powder, 30% sulfur powder, 20% molybdenum disulfide powder, and 10% nickel 60 powder, and a binder is added and mixed uniformly again to form a paste coating A;

[0035] (2) Adding a binder to the titanium dioxide material to form a paste-like coating B;

[0036] (3) Clean the surface of steel parts by pickling and alkali neutralization to remove surface oil stains, etc., and use a steel brush to roughen the surface of steel parts;

[0037] (4) coating A is applied to the surface of the steel part by spraying or the like to form a friction-reducing coating, and the coating spray thickness is 0.5 mm; then coating B is applied to form a protective layer, and the protective layer thickness is 0.1 mm;

[0038] (5) Heat the surface of the steel part to 1000°C and maintain it for 20 seconds, then apply pressure to press the coating material onto the steel part.

[0039] After testing, the coating thickness obtained in this embodiment can reach 300 μm; the surface hardness reaches HV300; and the friction coefficient is about 0.3.

[0040] Example 2

[0041] (1) The friction-reducing coating materials of the following mass components are mixed uniformly: 30% iron powder, 30% sulfur powder, 30% molybdenum disulfide powder, and 10% nickel 60 powder, and a binder is added and mixed uniformly again to form a paste coating A;

[0042] (2) Adding a binder to the titanium dioxide material to form a paste-like coating B;

[0043] (3) Clean the surface of steel parts by pickling and alkali neutralization to remove surface oil stains, etc., and use a steel brush to roughen the surface of steel parts;

[0044] (4) coating A is applied to the surface of the steel part by spraying or the like to form a friction-reducing coating, and the coating spray thickness is 0.5 mm; then coating B is applied to form a protective layer, and the protective layer thickness is 0.1 mm;

[0045] (5) Heat the surface of the steel part to 1000°C and maintain for 10 seconds, then apply pressure to press the coating material onto the steel part.

[0046] The coating thickness obtained in this embodiment can reach 250 μm; the surface hardness reaches HV300; and the friction coefficient is about 0.2.

[0047] Comparative Example

[0048] (1) The friction-reducing coating materials of the following mass components are mixed uniformly: 40% iron powder, 40% sulfur powder, and 20% molybdenum disulfide powder, and a binder is added and mixed uniformly again to form a paste coating A;

[0049] (2) Adding a binder to the titanium dioxide material to form a paste-like coating B;

[0050] (3) Clean the surface of steel parts by pickling and alkali neutralization to remove surface oil stains, etc., and use a steel brush to roughen the surface of steel parts;

[0051] (4) coating A is applied to the surface of the steel part by spraying or the like to form a friction-reducing coating, and the coating spray thickness is 0.5 mm; then coating B is applied to form a protective layer, and the thickness of the protective layer is 0.2 mm;

[0052] (5) Heat the surface of the steel part to 800°C and maintain it for 20 seconds, then apply pressure to press the coating material onto the steel part.

[0053] The coating thickness obtained in the comparative example can reach 200 μm; the surface hardness reaches HV240; the friction coefficient is about 0.24. It can be seen that the nickel 60 powder in the coating material is eliminated in the comparative example. Compared with Examples 1 and 2, the final coating thickness and the surface hardness of the steel part are reduced.

[0054] In summary, the steel surface sulfurization process of the present invention is used to treat the steel surface, so that a friction-reducing coating with good mechanical and tribological properties can be formed on the steel surface.

Claims

1. A steel surface sulfurizing process, characterized in that: The following steps are involved: (1) mixing the anti-friction coating material uniformly, adding a binder and mixing again uniformly to form a paste coating A; the anti-friction coating material comprises iron powder, sulfur powder, molybdenum disulfide powder, and nickel 60 powder; (2) mixing a protective layer material and a binder into a paste-like coating B; the protective layer material is titanium dioxide; (3) Clean the surface of the steel parts and roughen the surface of the steel parts; (4) coating A is applied to the surface of the steel part to form a friction-reducing coating, and then coating B is applied to form a protective layer; (5) The surface of the steel part is heated to form a friction-reducing coating having sulfide, and then pressure is applied to press the coating material onto the steel part.

2. The steel surface sulfurizing process according to claim 1, characterized in that: The mass components of the friction-reducing coating material are: 30-40% iron powder, 20-30% sulfur powder, 10-20% molybdenum disulfide powder, and 10-20% nickel 60 powder.

3. The steel surface sulfurizing process according to claim 1, characterized in that: The binder is a phosphate inorganic binder.

4. The steel surface sulfurizing process according to claim 1, characterized in that: The mass percentage of the binder in the coating A is 5-20%.

5. The steel surface sulfurizing process according to claim 1, characterized in that: The mass percentage of the binder in the coating B is 5-20%.

6. The steel surface sulfurizing process according to claim 1, characterized in that: The step (3) includes removing oil stains on the surface of the steel part by pickling and alkali neutralization, and roughening the surface of the steel part by a steel brush.

7. The steel surface sulfurizing process according to claim 1, characterized in that: The thickness of the anti-friction coating in step (4) is 0.1-0.2 mm.

8. The steel surface sulfurizing process according to claim 1, characterized in that: The thickness of the protective layer in step (4) is 0.3-0.5 mm.

9. The steel surface sulfurizing process according to claim 1, characterized in that: In the step (5), the temperature is heated to 800-1000° C. and maintained for 5-20 seconds.

10. The steel surface sulfurizing process according to claim 1, characterized in that: The heating method of step (5) is induction heating.