三种方法测定金属薄板塑性应变比值的结果比较

Comparing Results of Plastic Strain Ratio Values of Metal Thin Sheets Measured by Three Methods

分别采用半自动、全自动以及光学非接触式引伸计三种不同的方法,测定了四种不同厚度规格的DC03冷轧薄板的塑性应变比(r)值,将三种方法测定得到的试验结果进行比较,发现存在较大差异,进而分析了造成差异的原因。结果表明:半自动法测定的r值与光学非接触式引伸计法测定的r值较接近,试验结果具有较高的可靠性和重现性;而全自动法测定r值的可靠性和重现性却较差,主要是由于横向引伸计自动测量系统对横向变形量的测量不稳定,存在较大的测量误差;因此测定金属材料塑性应变比r值应优先用采用光学非接触式引伸计法,在手工装卸引伸计测定情况下,应优先选用半自动方法。

The plastic strain ratio r values of four different thickness sizes DC03 cold rolled thin steel sheets were tested by semi-auto, full-auto and video-extensometer three different methods respectively. Comparing the testing results of these three different methods, it was found that there was large difference among them, and then reasons for the large difference were analyzed. The results show that plastic strain ratio values tested by semi-auto method and video^extensometer method were nearly, and reliability and repeatability of these two methods were high. However, reliability and repeatability of full-auto method was low. It was mainly due to the measurement results of transverse extensometer automatic measurement system to the transverse deformation was uncertainty. So, when testing plastic strain ratio values of metallic material it should give priority to video-extensometer method, and in the case of manual handling extensometer, semi-auto method should be the preferred over full-auto method.