Super304H钢700℃时效后组织和韧性的变化

摘要

Microstructure and toughness changes of Super304H steel aged at 700℃rn was investigated using optical microscopy, scanning electron microscopy, X-ray diffraction and impact tester. Results show that M23 C6 carbide was precipitated during aging treatment. The amount of M23 C4 was increased rapidly at the initial stage and then became stable. M23C4 was precipitated along grain boundary in a chain-like manner, and with the increase of time its size increased rapidly. Aging brittleness of Super304H steel was attributed to the precipitation of M23 C6 along grain boundary, and the brittleness tended to be severe for the steel containing higher amount of M23C6.%利用光学显微镜、扫描电子显微镜、X射线衍射仪和冲击试验机等研究了Super304H钢在700℃时效过程中的组织和韧性变化。结果表明：Super304H钢在时效过程中析出了M23C6碳化物，其析出量在时效初期快速增加，一定时间后析出量趋于稳定，M23C6主要在晶界上呈链状分布，随时间延长尺寸很快长大；M23C6的沿晶析出引起了Super304H钢的时效脆化，且M23C6析出量越多钢的时效脆化程度越大。