在做金属拉力试验时,δ,(?)这二个指标的精确测量是非常重要的.可是如何保证测量的值精确呢?一方面取决于能用量具的精确度;同时还取决于如何固定拉断后试样的位置.由于试样拉断后,断口形状多种多样.如果不能将试样在断裂处紧密对接在一起,尽量使其轴线位于一条直线上,那么就会给测量结果带来很大的误差,有时断裂后试样的温度很高(做高温拉力试验时),这样就给试样固定工作带 Accurate measurements of δ, (?) Are very important when doing metallic tensile testing, but how to ensure that the value of the measurement is accurate depends on the accuracy of the measuring device, on the one hand on how it is fixed Pull off the sample position. As the sample pulled off, the fracture shape varied. If the sample can not be in close contact at the fracture together, try to make its axis in a straight line, it will give the measurement result is very Large error, sometimes after the specimen temperature is high (high temperature tensile test), so give the sample fixed working belt