一、前言为了提高火力发电锅炉的效率,近年来已普遍采用高温高压技术。而超临界压力发电设备的过热器管和二次加热管则多用SUS304,321,347HTB等奥氏体系不锈钢制成。该系钢虽比铁素体系不锈钢高温强度高,但因其热膨胀系数亦大,故在运转、停车时由于热膨胀或者收缩而会造成鳞片剥落,产生热传导性降低和应力腐蚀裂纹敏感等缺陷。因而对超临界特别是600℃以上的 First, the foreword In order to improve the efficiency of thermal power boiler, in recent years has been widely used high temperature and pressure technology. The supercritical pressure power generation equipment, superheater tubes and secondary heating tubes are mostly made of austenitic stainless steel such as SUS304,321,347HTB. Although the system of high strength ferritic stainless steel than high temperature, but also because of its thermal expansion coefficient is also large, so in operation, parking due to thermal expansion or contraction will cause flaking scales, resulting in thermal conductivity and stress corrosion cracking sensitive defects. Thus supercritical especially above 600 ℃