Shaft pin type steel chemical heat treatment method

Shaft pin 2020 - type steel chemical heat treatment method 04 - Wang (08 New northeast electric group high voltage switch equipment co. , LTD. ) The failure of mechanical parts and destroy most of germination in the surface layer, especially in under the working conditions can lead to wear and fatigue of components, the performance of surface layer is particularly important. Chemical heat treatment is the use of chemical reaction, sometimes combination of physical method to change steel surface chemical composition and organization structure, in order to get better than homogeneous material performance of metal heat treatment process. I company for shaft pin type steel usually adopt chemical heat treatment method of carbon altogether permeability, gas nitrogen to improve its wearability. But there are some parts after carbon and nitrogen altogether permeability appeared in the process of using a certain degree of occlusion phenomenon, it is necessary to find the reasons why this happens and process improvement methods. 1. Problems cause analysis was carried out on the shaft pin type steel carbon altogether permeability, nitrogen can improve its wearability. After chemical heat treatment of steel, in essence can be thought of as a special composite materials. The core for the original composition of the steel, surface is seeping into the material of alloy elements. Between surface and core is closely combined with crystal type, it is plating for surface protection technology such as heart, table is the combination of better. Iron and steel parts after forming cooperate relationship, under the large load matching surface between may have stuck together, that's bite. Occlusal phenomenon is the nature of the friction welding and mechanical alloying. Lack of lubrication and friction heat is the important reason for the occlusion occurs. Carbon and nitrogen altogether permeability make the carbonitriding layer on the surface of the steel is mainly composed of nitrogen compounds of carbon and nitrogen carbon solid solution. Carbon atoms in the process of carbon and nitrogen altogether permeability mainly acceleration, while nitrogen have the function of material surface hardness, because itself has a high hardness. Therefore, use the method of carbon nitrogen altogether permeability to improve the wear resistance of steel is implemented by increasing its surface hardness. In the mating surface without lubricant, tend to have a bite and possibility. 2. Process improvement method through the analysis of carbon to nitrogen gas instead of salt bath sulfur nitrogen carbon three yuan altogether permeability can solve the problem of occlusion. Sulfur nitrogen carbon altogether permeability is essentially the combination of sulfur and nitrogen carbon altogether permeability. Compared to carbon and nitrogen altogether permeability, sulfur and nitrogen carbon altogether permeability advantage can make the toughness and hardness of the coating on the surface of the steel with low sulfide layer, make good running in frictional contact surface, at the same time can be stored in the layer of microporous lubricating oil, and low coefficient of friction of sulfide itself, so the carbon sulfur nitrogen altogether permeability steel has good resistance to bite and anti-friction. In addition, due to the infiltration of sulfur, changed the hierarchical state nitrogen carbon compounds, reduces the permeability layer brittleness and scaling tendency. But carbon sulfur nitrogen altogether permeability layer of the friction and wear resistance is less than n carbon altogether permeability. In theory, three yuan after sulfur nitrogen and carbon altogether permeability surface to form carbon sulfur nitrogen compound layer, the layer is divided into the loose layer of outside and inside the dense layer of two parts, as shown in the appended drawings. Loose the aforementioned sulfide layer, is mainly composed of FeS, FeS2; Dense layer is mainly composed of nitrogen and carbon, nitrogen carbide has the characteristics of high hardness and high wear resistance. Therefore, steel after sulfur nitrogen three yuan carbon altogether permeability, the improvement of the surface wear resistance, is built on a dense layer of high hardness and low friction coefficient of porous layer on the basis of the combination. Sulfur, nitrogen, carbon three yuan altogether permeability after processing the microstructure on the surface of the steel shaft pin type steel mainly for my company of 45 steel, the salt bath sulfur nitrogen carbon ternary permeability at 565 ℃ for 150 min, CNO - Concentration of ( 34± 2) %。 Need to point out that the workpiece in different working condition of the wear resistance, antifriction, anti-seizure is slightly different, so in actual production, three yuan should be adjusted according to the performance requirements of sulfur nitrogen carbon altogether permeability process in the process of parameters such as temperature, time and concentration. Through the control of process parameters, can change the three yuan altogether permeability workpiece surface loose layer, density and the depth of compound layer, and then adjust their performance. 3. Conclusion using sulfur nitrogen carbon ternary permeability instead of carbon and nitrogen altogether permeability can be solved in the course of using the shaft pin type of steel in galling. Steel after sulfur nitrogen three yuan carbon altogether permeability, the improvement of the surface wear resistance, is built on a dense layer of high hardness and low friction coefficient of porous layer on the basis of the combination. In the actual production, can the carbon nitrogen in sulfur of three yuan including infiltration process parameters such as temperature, time and concentration of control to adjust the performance of the steel. Source: the metal processing ( Hot working) Magazine,