25Cr-6Ni-2Mo 系 2 相ステンレス鋼の応力腐食割れ挙動に及ぼすオーステナイト結晶粒径の影響

概要

論文の詳細を見る
The effect of γ grain size on stress corrosion cracking (SCC) behavior of a 25Cr-6Ni-2Mo duplex stainless steel was studied by means of constant load method in boiling 42%MgCl_2 solution. The main results obtained are as follows : (1) On heating at 950 or 1050℃, the growth of γ grain was nearly proportional to one-half power of holding time and SCC susceptibility increased with the grain growth of γ. By preparatory heating at 1150 or 1300℃ before the final heat treatment of 0.5h at 950℃, γ grain was coarsened remarkably and SCC susceptibility was increased up to that of SUS304. (2) On isothermal aging at 475℃ for long time, SCC susceptibility of the microduplex structure decreased remarkably as compared with that of the coarser structure. In the coarser structure, deformation twin formed easily in α by applied stress after aging, and it should be directly connected with the initiation of cracks. In the microduplex structure, however, did not form. (3) In both of the microduplex and coarser structure, the cracks propagated preferentially in α and the interface of α and γ similarly to the case of non-aging, and the crack restraining effect was observed in γ.
社団法人日本鉄鋼協会の論文
1983-05-01