合金元素及模拟热处理对2205双相不锈钢之孔蚀性质影响

本文研究了Ｎｉ元素及不同模拟焊后热影响区（ＨＡＺ）组织对２２０５双相不锈钢孔蚀性质之影响。结果发现：在研究成分范围内，不同Ｎｉ含量对于底材电化学极化曲线之影响不大，其Ｅｎｐ和Ｅｎｐ均在１１００￣１２００ｍＶ之间。

合金元素及模拟热处理对2205双相不锈钢之孔蚀性质影响

The effects of nickel content and Gleeble simulated heat affected zone(HAZ) of 2205 stainless steel on pitting corrosion were investigated in this paper. The results showed that nickel content, ranging from 4.5 wt% to 6.5 wt% in base metal, had only a minor effect on the electrochemical polarization curves, with all Enp's and Epp's falling in the rang of 1 1001200 mV. Comparing with the base metal, the simulated HAZ microstructure caused an increase in the anodic current density, a distinct decrease in both Enp and Epp , and a reduction in the passive range. Furthermore, hysteresis behavior was found as revealed in each cyclic polarization curve with different cooling cycle. It indicated that the pitting corrosion resistance and repassivation ability of duplex stainless steels were deteriorated by thermal cycling. Electrolytic extraction method proved that the Q values of integral cyclic polarization curves markedly increased while the nitrogen as Cr2N exceeded 20010-6. The susceptibility to pitting corrosion of HAZ was colsely related to the amount Cr2N precipitete. The higher the amount of Cr2N precipitated, the faster the rate of pitting propagation. However, in the nitride precipitate_free zones(PFZ), no pitting corrosion resistance was observed.