Study On Heat Treatment Process Of 316L Stainless Steel Formed By Selective Laser Melting

316L stainless steel has been widely used in aerospace,biomedical and other industries due to its excellent mechanical properties.The traditional manufacturing process is difficult to take into account the its plasticity while improving the strength of the 316L material.And the laser selective melting forming(SLM)technology provides the possibility to overcome this problem.The characteristics of rapid melting and solidification of the SLM process will produce unbalanced structure,coarse grains,high residual stress and other undesirable features of the formed parts,which will affect the performance of the formed parts to varying degrees.In view of the above problems,the main research contents of this article are as follows:(1)Through the analysis of the interaction mechanism between the laser and the metal powder,the reasons for the formation of the uneven structure and coarse grains of the SLM molded parts were explained,which laid the foundation for the formulation of the subsequent heat treatment process.And by analyzing different heat treatment methods and combining the characteristics of the SLM process,an annealing heat treatment process with the goal of refining crystal grains,improving structure,eliminating internal stress,and improving mechanical properties were determined.(2)On the basis of determining the heat treatment process method,the SLM-316L samples under the same process parameters were subjected to annealing heat treatment at different holding temperatures.The effects of annealing temperature on the microstructure evolution and phase structure were characterized by scanning electron microscope(SEM)and X-ray diffraction(XRD).And the effect of annealing temperature on the conventional mechanical properties such as microhardness,tensile strength,and impact strength of slm-3161 was studied.(3)The friction characteristics of the SLM-316L parts are emphatically considered.Through the friction coefficient,surface wear scar morphology and wear rate and other characterizing parameters,the difference in tribological properties of different forming surfaces of the part under different wear loads was analyzed.While the effect of annealing heat treatment system on its friction and wear performance was analyzed.(4)On the basis of the above research,based on the rapid development of new products technical route,the application case of the key parts of the knife board has been formed.Through analysis of tool performance requirements,combined with finite element simulation and prototype bench test,the effectiveness of the above research was verified.It provides a reference for the formulation of standard SLM forming parts heat treatment process.