Numerical simulation of temperature field of wear-resistant anti-corrosion laser cladding self-lubricating coating on 300 M super-strength steel

Abstract

In order to improve the anti-wear properties of 300M super-strength steel for aircraft landing gear shock absorbing strut, and to break through the technical bottleneck such as cracks induced by the excessive temperature gradient in laser cladding wear-resistant anti-corrosion self-lubricating coating, the "birth and death" method and the APDL procedure of ANSYS were used to simulate the molten pool's thermal cycle for the 300M super-strength steel's laser cladding wear-resistant anti-corrosion self-lubricating coating. The change of thermophysical parameters with different temperatures for self-lubricant and wear-resistant materials , latent heat in phase change, external heat exchange during laser cladding, laser cladding power, laser cladding scanning velocity and other factors, which affect the temperature field, molten pool, temperature gradient during the laser cladding process were considered. The results indicate that the melting of the substrate requires a combination of laser and molten powder, etc. to bring the effective energy conducted to the region reach the critical value of melting, the increase rate of the melting height of the substrate decreases first and then increases with the increase of the laser power, the decrease rate of the melting height of the substrate decreases first and then becomes larger with the increase of the laser scanning speed. Due to the comprehensive factors of different temperatures and cooling rates in different laser cladding areas, the vertical section of the laser cladding wear-resistant anti-corrosion self-lubricating coating bath is a spoon-shaped molten pool. With the increase of the laser power, due to the difference in the temperature response of the energy input to different regions of the cladding layer, the temperature gradient in the Z-direction and the maximum cooling rate increases. With the increase of laser scanning velocity, the laser input energy decreases, which decreases the combined effects of high-temperature region temperature and rapid local heating of the laser. Meanwhile, the temperature gradient in the Z-direction decreases. Under the condition of maintaining the bonding strength of the cladding layer, the substrate melting zone can be controlled to minimize and lower the temperature gradient by controlling laser parameters reasonably.

Keywords

• laser cladding
• self-lubricating
• 300m steel
• temperature gradient