Plasma cleaning machine plasma nitriding composite coating structure laser cladding and activation screen:
Tooth parts are important parts that transmit loads and motions in mechanical systems. Under cyclic loads and long-term wear conditions, tooth parts often fail due to tooth surface damage or tooth body damage, and tooth failure directly affects the normal operation of the mechanical system. Due to the large number of teeth and the high cost of action, remanufacturing the teeth has significant economic benefits.
Laser cladding technology is one of the advanced remanufacturing technologies. It can repair the surface damage of parts and repair the volume damage of parts. It has the advantages of high performance and excellent bonding strength between the coating and the substrate, small damage to the substrate, and high processing accuracy. It has been applied in the remanufacturing of tooth parts.
However, with the substantial improvement in the performance of various mechanical power devices, the performance requirements for high-speed, heavy-duty and high-reliability gears are becoming more and more demanding. How to further improve the performance of laser remanufactured tooth parts is of great significance for improving the reliability and life of laser remanufactured parts.
The composite processing technology can give play to the respective advantages of different technologies, learn from each other's strengths, and cooperate organically to effectively improve the use performance of parts.
Plasma cleaning machine plasma treatment technology is one of the advanced surface treatment technologies. It overcomes the shortcomings of traditional nitriding technology (such as workpiece arcing, hollow cathode effect, etc.). The formed nitride layer not only improves the surface hardness of the material, but also Moreover, residual compressive stress is formed on the surface of the material, which is beneficial to improve the wear resistance and contact fatigue resistance of the material, and prolong the service life of the tooth parts.

After the composite treatment, the hardness of the Fe314 laser cladding layer is increased from 540 HV to 927 HV. The hardness of the coating has been greatly improved. This is because laser cladding has the characteristics of rapid heating and rapid solidification. The formed structure is relatively small, the solid solubility is large, and the solid solution strengthening effect is significant, which is beneficial to the injection of nitrogen atoms. A dense nitride layer is formed on the surface. After chemical treatment, the microhardness of the cladding layer increases significantly.
Fe314 laser cladding layer is mainly damaged by pitting and spalling pits. This is because the hardness of the surface layer of the sample is low and plastic deformation is easy to occur along the sliding direction. The closer to the surface, the more serious the plastic deformation. As the cycle progresses, the cumulative damage gradually increases and cracks are easily formed on the surface.
Under the repeated action of contact stress, the size of the crack gradually increases. When the crack expands to a sufficient length, lubricating oil can enter. Under the action of pressure, the crack forms a tiny closed area, and the oil pressure in this area increases sharply, causing the crack to continue to expand in depth, causing the small piece of metal between the crack and the surface to be like a bent cantilever beam, and then at the root. Broken, forming a flaking pit on the surface. After the composite treatment, only slight pitting damage occurred on the surface, indicating that the contact fatigue performance of the Fe314 laser cladding layer was significantly improved after the composite treatment.
The main reason for the improvement of the fatigue life of the cladding layer after the composite treatment is that the high damage defects generated by the ion implantation of the plasma cleaner prevent the movement of dislocations and improve the bearing capacity of the material. At the same time, the increase in surface hardness can reduce the plastic deformation of the metal surface under force, thereby reducing the probability of crack nucleation; on the other hand, after nitriding treatment, the surface will form residual compressive stress, which can greatly offset the external shear stress. The detrimental effect of it is beneficial to inhibit the initiation and propagation of surface cracks.
Contact fatigue is a phenomenon of surface spalling and damage caused by the cycle of contact pressure stress on the surface of the gear, which is a process of cracking and propagation.
Generally speaking, the higher the hardness, the higher the contact fatigue resistance, and the lower the hardness, the lower the contact fatigue resistance. High hardness, high shear resistance and cutting resistance, can prevent the surface layer from cracking caused by the increased surface shear stress of various reasons, thereby improving the fatigue strength of the surface layer. If the surface is soft, the cracks are likely to nucleate and increase the probability of pitting damage on the surface. Therefore, the surface hardness must be increased to increase the cutting resistance of the surface, reduce the deformation of the metal surface under the force, reduce the probability of crack formation, and prevent pitting damage.
Since the plasma treatment technology of the plasma cleaner can effectively improve the surface hardness of the material and reduce the surface tensile stress, it can effectively improve the contact fatigue resistance of the laser cladding layer, thereby further improving the performance of the parts after laser remanufacturing.