00Cr18Ni5Mo3Si2双相不锈钢晶间腐蚀性能的研究

INTERGRANULAR CORROSION BEHAVIOR OF OOCr18Ni5Mo3Si2 DUPLEX STAINLESS STEEL

本文研究了高温热处理后00Cr18Ni5Mo3Si2双相不锈钢(18-5钢)的晶间腐蚀性能。由于高温敏化加热后水冷时,沿α/α晶界和α/γ相界析出M_(23)C_6型富铬碳化物,导致碳化物附近的贫铬区,使18-5钢在EPR法和T法中均产生晶间腐蚀。高温敏化加热后空冷时,M_(23)C_6型碳化物和大量羽毛状γ′相沿晶界析出,但经EPR法和T法检验,均无晶间腐蚀倾向。无论空冷或水冷,高温热处理得到粗大铁素体晶粒的18-5双相不锈钢,在T法试验后弯曲时,均发生脆性断裂。

The influence of high temperature heat treatment on inter-granular corrosion ( IGC ) behavior of 00Cr18Ni5Mo3Si2 duplex stainless steel was investigated. The alloy heat-treated at high temperature ( above 1200 ℃) -was susceptible to IGC in the T test and EPR test because of the formation of chromium depleted zone near the grain boundaries caused by the intergranular precipitation of chromium-rich M23-C6 during water quenching. Samples aged at high temperature and followed by air cooling were immune to IGC in T test and EPR test regardless of the precipitation of M23C6 and a large amount of feather-like γ' along grain boundaries. After ageing at high temperature, followed by water quenching or air cooling, this alloy contained coarse ferrite grains and fractured brittlely in the process of bending subsequent to IGC test ( T method ) .