目前是看最新版的E8/E8M 以下文字有点多 可先直接看段落下方中文 撷取部分文字 因为我有点被搞混到底想知道YS UTS ELONGATION 的速率规定是上限还固定还下限 7.6.3 Speed of Testing When Determining Yield Properties— Unless otherwise specified, any convenient speed of testing may be used up to one half the specified minimum yield strength or up to one quarter of the specified minimum tensile strength, whichever is smaller. 上限为1/2的决定YS速率or1/4的决定UTS用速率两者较小值? 还是说另外有规定specified YSmin的速率为多少? The speed above this point shall be within the specified limits. If different speed limitations are required for use in determining yield strength,yield point elongation, tensile strength, elongation, and reduction of area, they should be stated in the product specifications. In all cases, the speed of testing shall be such that the forces and strains used in obtaining the test results are accurately indicated. Determination of mechanical properties for comparison of product properties against a specification value should be run using the same control method and rate used to determine the specification value. 想同时取得YS UTS的机性应用同一种方法及速率(但之後却又分别有规定? ====================================================== 7.6.3.2 Control Method B - Rate of Straining Control Method for Determining Yield Properties — In this method, the testing machine shall be operated in closed-loop control using the extensometer signal. The rate of straining shall be set and maintained at 0.015正负0.006 mm/mm/min [in./in./min]. NOTE 23—A Rate of Straining at 0.005 mm/mm/min [in./in./min] is often required for aerospace, high-temperature alloys, and titanium applications and when specified, must be followed rather than the requirement above. 这里看不太懂为什麽可以是例外? 前一段应该是0.009~0.021的规范 ====================================================== 7.6.3.3 Control Method C—-Crosshead Speed Control Method for Determining Yield Properties– The testing machine shall be set to a crosshead speed equal to 0.015正负0.003 mm/mm/min [in./in./min] of the original reduced section ====================================================== 7.6.4 Speed of Testing When Determining Tensile Strength— In the absence of any specified limitations on speed of testing, the following general rules shall apply for materials with expected elongations greater than 5 %. When determining only the tensile strength, or after the yield behavior has been recorded, the speed of the testing machine shall be set between 0.05 and 0.5 mm/mm [or in./in.] of the length of the reduced section (or distance between the grips for specimens not havinga reduced section) per minute. ====================================================== 这里是说如果也有要测得YS就依照YS规定的速率吗? 不过似乎认识的人也都不太在意到底速率多少 可能就说 "金属喔 大概就strain 10的-3次方/sec左右吧 结果就有些拉个2分钟 有些拉个20分钟 想请益大家是看材料决定 还是看学长姐或老师有规定? 谢谢 --

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