高温螺栓失效研究

Study on Failure of High Temperature Bolt

通过对高温螺栓的失效研究,发现在原奥氏体晶界上产生碳化物,形成网状晶界,使材料强度和冲击韧性下降,脆性增加。结果表明,螺栓在高温下长期工作,产生高温蠕变,使蠕变强度下降;当预紧力过大及受到交变应力作用时,在应力集中处产生裂纹源,裂纹源逐渐形成微裂纹;随微裂纹的扩展,螺栓失效。

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 rcsults 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 micro-cracks, the bolt becomes invalid.