Effect of Aging Temperature on Corrosion Behaviors of 17-4 PH Precipitation-hardening Stainless Steel in Waste Sulphuric Acid

After aging treatment 17-4PH stainless steel has excellent mechanical properties and good corrosion resistance,and is extensively used in the filed of petrochemical engineering,chemical engineering and aerospace.In this paper,the effect of the aging temperature on the mechanical properties and corrosion behaviors of the 17-4PH stainless steel in waste sulphuric acid was investigated.The results showed that with the increase of aging temperature,the yield stress and the tensile stress of the 17-4PH stainless steel decreased,and the reduction of area and elongation increased.The fracture mode transformed from brittle fracture to ductile fracture.The free corrosion potentials of 17-4PH stainless steels after different aging temperature were E550 ℃>E620 ℃>E580 ℃.The immersion experiments showed that the corrosion resistance of the 17-4PH stainless steels aged at 550 ℃ was best,at 620 ℃ was second and at 580 ℃ was last.