Rheological, mechanical and corrosive properties of injection molded 17-4PH stainless steel
(State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China)
Abstract: The feedstock based on the binder 65%PW-30%EVA-5%SA has the best general rheological properties for the 17-4PH stainless steel powder. The 17-4PH stainless steel compacts sintered at 1 380 ℃ for 90 min have the best mechanical properties and the good microstructure with homogeneously distributed pore structure and the moderate-sized grains. Whereas the compacts sintered for 60 min and 120 min show an inadequate and an over-sintered microstructure respectively. The compacts sintered at 1380 ℃ for 90 min have the density of 7.70 g/cm3, the strength of 1 275 MPa, the elongation of 5%, and hardness of HRC36. With the increase of sintering temperature, the density, strength and hardness increase, while the elongation decreases. The 17-4PH stainless steel has good corrosion resistance, showing an activation-passivation polarization curve. But the passivation potential range is narrow and the spot corrosion potential is low, indicating a low anti-spot corrosive properties.
Key words: metal injection molding(MIM); rheological properties; mechanical properties; corrosive resistance; 17-4PH stainless steel