湿式エメリー研磨により導入された極僅かな冷間加工が ニッケル基合金の水蒸気酸化挙動に及ぼす影響
Effect of slight cold work introduced with fine emery finish on oxidation and cracking behaviours of Ni base alloys in hydrogenated steam
著者:
熊谷 大介 Daisuke KUMAGAI 阿部 博 Hiroshi ABE 渡邉 豊 Yutaka WATANABE INSA Lyyo Fethi HAMDANI Fethi HAMDANI
発刊日:
公開日:
CrackingNi base alloySteam oxidationSurface preparation
概要
Wet polish with fine emery paper is most commonly used for final finish of SCC specimens and corrosion coupons. Although cold w ork introduced by the fine emery finish is slight, a series of experiments have demonstrated that the very slight cold work can ffect oxidation behaviors and apparent SCC susceptibility of Ni base alloys in hydrogenated steam. Oxidation tests and reverse type SCC experiments have been done in hydrogenated steam at 400C for Ni-Cr binary alloys with various Cr content from 14% t o 30% and with variety of surface finish. Specimens with colloidal silica-polished clearly showed poorer resistance to oxidatio n and cracking compared with the emery-polished specimens. Enhanced mobility of Cr in the very surface region would be the prim y reason for the improved oxidation resistance of the emery-polished specimens. The results indicate the importance of the ver slight cold work, which can be introduced even with the fine emery finish, in evaluation of SCC initiation of Ni base alloys.
