The Study Of Process And Properties Of 316L Stainless Steel Injection Molding

The volume fraction of binder in the 316L stainless steel injection molding technology is relatively large. The binder system is more complicated at the same time, so choosing a suitable binder is very important for dimensional accuracy and mechanical properties of 316L stainless steel MIM products. In addition, thermal debinding method is most commonly used in the debinding process of 316L stainless steel, and the research of solvent debinding is relatively less. Therefore, this paper compares the effects of three backbone polymers, HDPE, HDPE/PP, PP, on the dimensions and mechanical properties of 316L green and sintered parts. The solvent debinding and sintering process are also further optimized.The results show that the corresponding MIM processs are determined by analysis of three feedstocks, and the distribution of structures is uniform. Feedstock B performs better than others in terms of the dimensional stabilities and mechanical properties of green parts and sintered parts. The feedstock B shortens the time of solvent debinding and optimizes the solvent debinding process. Most of PW in the binder close to 62.2% are removed in 2h.The effect of the type of solvent, the debinding temperature, the debinding time and the sample thickness on solvent debinding is compared. The solvent debinding process is optimized. PW can be substantially removed in n-heptane at 60℃ for 6h, and there is no defect in the sample. The kinetic of solvent debinding process is also analyzed, which provides a theoretical basis for the actual production.Sintering is the main stage of densification of samples, and it is also the key step in the process of metal injection molding, which determines the final performance, dimensional accuracy and microstructure of the product. Through the use of different sintering temperature, the dimension, mechanical properties and microstructure are analyzed. The sintering process is also optimized. The debound parts are sintered at 1380℃ for 3h under argon gas. The sintered samples have good morphology, uniform grain size and good mechanical properties.