高クロム鋼溶接部のクリープ強度特性と実機溶接配管の内圧曲げクリープ試験(<特集>第14回動力・エネルギー技術シンポジウム)

Abstract

Creep tests on 9 Cr and 12 Cr steels welded joints were conducted under internal pressure conditions as well as uniaxial stress conditions. For both materials, failure occurs at fine grain HAZ region under long time region, which means type IV damage. SEM observation was carried out on internal pressure test specimens of the welded joints. It was found that density of creep voids is higher in mid-thickness of the HAZ portion than that in outer and inner surfaces. Furthermore, a recently developed demonstration test facility, which can load bending forces and internal pressure on actual boiler pipes at high temperatures, is briefly introduced in this presentation.