超声检测技术用于评价20钢高温组织转变

Application of ultrasonic testing in evaluating 20G high temperature microstructure transformation

讨论了20钢高温时效组织与超声波速度间的相关性。结果表明:随着时效时间的延长,珠光体中的片状渗碳体逐渐球化并沿晶界聚集成网状,声速以指数规律递减。分析认为:高温时效过程中,珠光体中渗碳体形态、数量及分布的改变在某种程度上削弱了原子间结合力,引起弹性模量E下降,导致超声波速度减小。因此,选择超声检测技术无损评价20钢高温时效组织状态是可行的。

The correlation between ultrasonic velocity and microstructure in 20G aged at high temperature is discussed. The results show that, with the increasing aging time, the lamellar cementite in pearlite spheroidized and congregated to network structure along the grain boundaries gradually.The ultrasonic velneity reduces according to the index law.It is analyzed that during aging, the variation of the shape and distribution of cementite weakens the inter-atomic bonding force to some extent, which is related to elasticity modulus, and results in the reducing of velocity.Hence, it is feasible to choose ultrasonic velocity as a useful tool for evaluating the microstructure transformation in 20 - steel aged at high temperature.