摘要
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．然而不同冷速之Ｇｌｅｅｂｌｅ模拟ＨＡＺ组织，其极化曲线不但阳极电流密度增加，Ｅｎｐ及Ｅｎｐ下降，钝态区域缩小，且循环扫描以后有明显迟滞现象．显示经过不同冷却时间之热履历，已破坏２２０５双相不锈钢抗孔蚀能力，而蚀孔形成后之再钝化能力也变差．电解分离分析法证实形成Ｃｒ２Ｎ之Ｎ含量超过２００×１０－６时，循环极化曲线积分之Ｑ值有显著增加之趋势，显示ＨＡＺ组织抗孔蚀性质能力主要和Ｃｒ２Ｎ析出量多寡有关，Ｃｒ２Ｎ愈多，孔蚀生长之速率也愈快．但部份ＨＡＺ组织会形成Ｃｒ２Ｎ无析出区。
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.
出处
《电化学》
CAS
CSCD
1999年第2期130-139,共10页
Journal of Electrochemistry
