| 316L stainless steel is an important structural material for preparing nuclear reactor parts and petrochemical pipes.316 L stainless steel parts are generally manufactured by machining forged or cast blanks.In the context of increasing requirements for reliability,microstructure,mechanical properties,and service conditions of materials produced by traditional processing techniques,they are no longer able to meet the service conditions in some fields.Improving the process flow and adopting advanced processing technologies to improve the complexity,microstructure,and mechanical properties of components has gradually become a development direction.Additive manufacturing and powder metallurgy hot isostatic pressing have emerged,but the differences in post treatment processes for additive manufacturing and the impact of powder metallurgy hot isostatic pressing process parameters are still unclear.Based on this,this article uses hot isostatic pressing to treat 3D printed 316 L stainless steel and studies the effect of hot isostatic pressing on the microstructure of 3D printed 316 L stainless steel;The influence of powder particle size distribution and hot isostatic pressing temperature on the microstructure and tensile properties of powder hot isostatic pressing 316 L stainless steel was studied.The main results were as follows: after hot isostatic pressing treatment,the pores and microstructure of 3D printed 316 L stainless steel were significantly improved,and the degree of recrystallization was significantly improved.However,the unique microstructure formed during 3D printing would produce dislocation pinning and hinder complete recrystallization.The recrystallization degree of the material treated at1180 ℃ has further improved compared to that treated at 1150 ℃.Therefore,hot isostatic pressing has broad application potential in the field of 3D printing material post-processing.Six groups of samples were prepared by hot metallurgy isostatic pressing at 1140 ℃ and1180 ℃ for 316 L stainless steel powder with particle size distribution of 15-53 μm,53-105μm,15-105 μm powder.There are very small amounts of small angle grain boundaries(about0.1 %)in the samples,while the rest are random large angle grain boundaries and twin boundaries.The material has uniform grain size,and the majority of grains have no obvious preferred orientation.No obvious texture was found,but the hot isostatic pressing temperature has a significant impact on the number of twin boundaries in the material.The powder size distribution and HIP temperature have no obvious influence on the yield strength and ultimate tensile strength of powder HIP 316 L stainless steel,but the HIP temperature has a greater influence on the elongation of the material.Powder metallurgy hot isostatic pressing 316 L stainless steel exhibits better tensile properties and elongation than stainless steel manufactured by conventional production methods,with a completely plastic dimple fracture mode.Therefore,powder hot isostatic pressing may serve as a superior substitute for 3D printing in the field of preparing highly reliable and high-performance components,and has broad development potential. |
PDF Full Text Request