室温拉伸试验的不同速率控制模式对判读低碳钢下屈服点的优劣对比

在金属材料室温拉伸试验中,应变速率控制和位移速率控制是两种常用的控制模式。本文通过在实际试验操作中获得的数据、曲线来说明位移速率控制在材料下屈服点判读方面的劣势和应变速率控制在下屈服点判读方面的明显优势。应变速率控制测得的试验力-变形曲线上、下屈服点一目了然,易于判读,下屈服强度易于计算;位移速率控制测得的试验力-变形曲线在上屈服点附近纠结杂乱,下屈服点难以判别。同时,笔者还发现应变速率控制在试样屈服瞬间由于试样表面产生滑移现象导致试验机不能准确监控试样变形即会造成试验机短时间失控,这是应变速率控制的一大难点。关于这一难点,本文还给出了假想解决方案。

Different Rate Control Mode at Ambient Temperature Tensile Test to Determine the Advantages and Disadvantages on Lower Yield Point of Low-carbon Steel

Strain rate control and displacement rate control in the metallic materials tensile testing at ambient temperature is two kinds of in common use control method.This article is attempting to explain the obvious advantages of strain rate control and the disadvantages of displacement rate control via plenty of data which is from tests.The upper yield point and lower yield point at Stress-transform diagram measured by strain rate control are clear at a glance,easy to judge.And,the lower yield strength measured ...