摘要
为了找出汽门螺栓断裂原因,采用超声波粗晶分析、化学成分检测、力学性能检测、显微组织分析及SEM断口微区分析等技术对600MW汽轮机断裂螺栓进行综合性检测试验分析。结果表明,使用超声波技术可以有效地检测出材质为20Cr1Mo1VTiB的高温螺栓是否存在粗晶。螺栓断裂是由于部分螺栓遗传了热加工过程中的粗大晶粒组织,严重降低了材料的塑性和冲击韧性,致使其在汽门频繁动作时的冲击载荷作用下沿应力最为集中的丝扣处发生断裂。
In order to obtain cause of valve bolts cracking and prevent cracking accident occur once more, methords of ultrasonic detection, chemical composition analysing, mechanical property detection, microstructure an- alysing and SEM analysing were used to analyse the valve bolts of 600 MW turbine. Results illustrate that it is effec- tive to use ultrasonic technology to detect coarse grain of 20CrlMolVTiB bolts. In the mean time, the coarse grain size of cracking valve bolts is responsible for reducing the plasticity and dynamic ductility of bolt heavily. The bolts shall be breaked in screw where heavy stress concentration occurs when frenquent impulse load is acted on it.
出处
《无损检测》
2014年第12期76-80,共5页
Nondestructive Testing
关键词
汽门螺栓
超声波
粗晶
冲击韧性
断裂
Valve bolt
Ultrasonic
Coarse grain
Dynamic ductility
Cracking
