取样长度和测试速率对冷轧金属薄板表面粗糙度测试的影响

Effect of Sampling Length and Testing Speed on Measurement of Roughness Average R_a on Cold Rolled Steel Sheet

为解决冷轧金属薄板表面粗糙度测试欧系标准SEP 1940-2002中采用2.5 mm的取样长度与国标GB/T 2523-2008中采用0.8 mm的取样长度的差异问题,开展了专项对比试验,并对试验数据进行了绝对误差和相对误差分析。结果表明:面对目前国内毛化加工冷轧金属薄板表面粗糙度R_a处在0.5~2.0μm的实际情况,采用0.8 mm的取样长度,符合欧系和日系表面粗糙度测量仪的测试参数设置要求;且采用2.5 mm的取样长度与采用0.8 mm的取样长度对R_a测试结果影响不大。同时,还对日系汽车厂材料试验室测试R_a采用0.2 mm·s^(-1)的测试速率与国标GB/T 2523—2008中要求采用0.5 mm·s^(-1)的测试速率的差异问题进行了对比试验,试验数据显示两种测试速率得到的R_a无明显差异。

For solving the problem of differences between 2. 5 mm sampling length adopted by European standard （SEP t940--2002） and 0. 8 mm sampling length adopted by national standard （GB/T 2523-2008） in measurement of roughness average Ra on cold rolled steel sheet, special contrast test was carried out, and the absolute error and relative error of the testing data were analyzed. The results indicate that facing with the actual condition in China, the Ra on cold rolled steel sheet at 0. 5- 2. 0 μm, adopting 0. 8 mm sampling length corresponded to testing parameter setting requirement of European and Japanese surface roughness average testing instruments, and the sampling length of 2.5 mm and 0. 8 mm had less impact on the testing results. What＇s more, contrast test was also carried out between 0. 2 mm·s^（-1） testing speed adopted by material laboratory of Japanese automobile factory and 0.5 mm ·s^（-1） testing speed adopted by GB/T 2523-2008, and the testing data indicate that the actual Ra testing results with two different testing speeds were the same.