Study On Thermal Deformation Behavior And Heat Treatment Process Of 0Cr13Ni8Mo2Al Stainless Steel

Precipitation hardening stainless steel has been used in the key structures of aviation, spaceflight, oceaneering and other advanced equipments widely for its high strength and toughness and well corrosion resistance. In this paper,0Cr13Ni8Mo2A1 stainless steel was a kind of martensite precipitation hardening stainless steel which had outstanding property. But it was easy to have composition segregation and coarse columnar crystal sites and other metallurgy problems because of its high contents of alloying elements. In other to ensure forging organization evenly, it had to know the best parameter of forging technology. Meanwhile, in the process of aging treatment, the type and regularity of precipitated phase was more complicated and precipitation strength was an important strengthening mechanism for 0Cr13Ni8Mo2A1 stainless steel and the precipitated phase had great influence on corrosion resistance Therefore, it was particularly important to research the hot deformation and heat treatment influence on its mechanical property and corrosion resistance.Using Gleeble-3800 thermal simulation experiment machine, the paper studied on the hot deformation behavior of 0Cr13Ni8Mo2A1 stainless steel within the scope of 900～1200℃ deformation temperature and strain rate between 0.01～10 s-1,which constructed the thermal deformation equation, and drawn the processing map. Combined with the processing map and microstructure, it determined the optimum hot working range.Treating 0Cr13Ni8Mo2A1 stainless steel at 850～1000 ℃ within the scope of solution and through the mechanical property test, it found that the solution treatment of this steel would get good comprehensive mechanical property around 925℃. Meanwhile, it studied the influence law of steel’s organization and mechanical properties by the aging treatment between 510 to 620 ℃. After aging treatment, the matrix structure of 0Cr13Ni8Mo2A1 stainless steel was tiny lath martensite. M2C, NiAl and Ni3A1 second phase particles separated out from the process of aging treatment distribute between the matrix structures diffusely. They can hinder dislocation motion and improve the strength of steel. Retained austenite content of 0Cr13Ni8Mo2A1 stainless steel increased with the temperature of aging treatment up. It led to decrease the steel’s tensile strength and yield strength. Membrane of retained austenite between martensite lath could also improve the toughness of steel.This paper did some research on pitting corrosion resistance property of 0Cr13Ni8Mo2A1 stainless steel under different heat treatment process by using FeCl3 solution immersion method and cyclic polarization curve test. It found 0Cr13Ni8Mo2A1 stainless steel after solution treatment and cold treatment had good pitting corrosion resistance property, and pitting potential was higher. Once after aging treatment, its pitting corrosion resistance, and pitting potential would be declined. It is due to a large number of second phase particles separated out in the aging treatment, and destroyed the homogeneity of material organization.