汽轮机缸体用钢高温时效韧性与组织研究

Study on High Temperature Aged Toughness and Structure of Steam-turbine Cylinder Body Steel

本文采用仪器化冲击试验方法及微观组织分析方法,对汽轮机缸体用钢在593℃不同时间时效条件下的动态断裂韧性及显微组织进行了研究。动态断裂试验结果表明,经过438 h时效,KId值比未时效试样下降了9.5%;时效2 105 h与时效438 h相比,KId值差异不大,趋于稳定。断口分析表明,剪切唇厚度和侧膨胀值随时效时间的变化趋势与KId值随时效时间变化趋势相一致。SEM微观组织形貌和能谱分析表明,时效438 h后,晶内与晶界均析出少量碳化物,且部分碳化物颗粒发生聚集和长大;时效438 h至2 105 h,碳化物尺寸及数量变化不大,显微组织趋于稳定。

The dynamic fraCture toughness and microstructure of stream-turbine cylinder body steel under differenttime aging at 593℃ was studied by instrumented impact test and microstructure analysis. The results from dynamic fracture test show that Kidafter 438h aging is reduced by about 9.5% than that before aging. Compared with that aging for 438 h, Kzdafter aging for 2105 h changes little and tends to stabilty. Fracture analysis shows that the with aging time changing trend of shear lip thickness and side-swell value is in conrrespondence with the changing trend of Kid. Structure and energy spectrum analysis by SEM shows that a small amount of carbide is precipitated from intracrystalline and intergranular, and some carbide particles agglomerate and grow. The dimention and quantity of carbide change little and the structure keeps stable when aging from 438h aging to 2 105 h.