By analysis of failure of high temperature bolt, the carbide which is found in the original austenite grain boundaries forms a network of grain boundary. The material strength and impact toughness decrease, and increase fragility. The results show that the bolts have long-term work at high temperature, high temperature creep, creep strength decrease preload by alternating the role of stress cracks in the stress concentration at the source. The crack source gradually forms micro-crack. With the expansion of ...