【摘要】 GB/T 228-2002《金属材料室温拉伸试验方法》规定,管段压扁试样平行长度只要大于等于标距长度与二分之一直径的长度之和即可。在实际执行中发现,在满足这一要求的前提下,平行长度对管材的延伸率测量值有很大影响,难以反映材料本身的真实塑性。本文通过试验对这一结论进行论证,并建议今后修订GB/T 228-2002《金属材料室温拉力试验方法》时,规定管材拉伸试验采用塞头管段试样。更多还原

【Abstract】 It is specified in the GB/T 228-2002 "metallic materials—tensile testing at ambient temperature" that the length of parallel section of tube specimen for tensile test should be as long as not less than the sum of marked length and half a diameter.But it is discovered that the parallel length has great influence on the tested elongation even though the length of tube specimen meets the above mentioned specification,so the test results cold not reflect the real ductility of the material itself.This article describes this phenomenon and analyzes the reasons resulted from and give some suggestion about the correct type of tube specimen which should be taken when the national standard of "metallic materials-tensile testing at ambient temperature" is revised next time.更多还原