超超临界机组不锈钢Super304H高温运行后的性能研究

Study on the Performance of Stainless Steel Super304H Used for the Ultra Supercritical Unit after Service at High Temperature

对某超超临界机组高温运行达到50000 h的奥氏体不锈钢Super304H管段取样进行了性能试验研究,结果发现:Super304H运行50000 h后的室温抗拉强度有所增加,屈服强度明显降低,650℃拉伸性能变化不明显,冲击吸收能量显著下降,硬度明显增加。金相组织正常,未发现脆性σ相;析出相主要为MX和碳化物M23C6;内壁氧化皮形成了保护性能良好的抑制膜,可有效减缓氧化皮的生长速度。

The performance test of the austenitic stainless steel Super304H pipe section of an ultra-supercritical unit running at high temperature up to 50000h was carried out.The results show that the tensile strength at room temperature increased,the yield strength obviously decreased,the tensile property at 650℃was not obvious changed,the impact absorption energy significantly decreased,and the hardness obviously increased after running for 50000h.The metallographic structure was normal and no brittle-phase.The precipitated phases are mainly MX and carbide M23C6.The inner oxide scale formed a good protective film,which can effectively slow down the growth of oxide scale.