Abstract

Failure of an St3sp steel sample under uniaxial tension and fatigue is studied using metallographic and ultrasonic pulse-echo techniques. Samples are cut out from a welded joint, particularly from a parent metal area and an incomplete recrystallization area in the heat-affected zone. The evolution of persistent slip bands in the heat-affected zone and those in the parent metal are subjected to a comparative analysis. A relationship between Poisson’s ratio determined by the ultrasonic method and the mechanical characteristics of the material is established. Methods for estimating the plasticity life under uniaxial tension and the number of cycles before fatigue failure are proposed.

中文翻译：

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碳钢焊接接头塑性变形和疲劳热影响区的超声及金相研究

摘要

使用金相和超声波脉冲回波技术研究 St3sp 钢样品在单轴拉伸和疲劳下的失效。从焊接接头处切取样品，特别是从母材区域和热影响区的不完全再结晶区域切取样品。对热影响区和母材中持久滑移带的演变进行了比较分析。建立了超声波法测定的泊松比与材料力学特性之间的关系。提出了估计单轴拉伸下塑性寿命和疲劳失效前循环次数的方法。