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本工作应用一种鋁管微型拉伸試样,測定了由于改变其尺寸和加工技术条件而引起的拉伸试驗結果的变化。所改变的尺寸和加工技术条件有:試样工作部分寬度(b)、长度(l)、表面光洁度、加工变形、台阶錯位(△l)、台阶不垂直度(△h)、根部缺口深度(a)及厚度差(△f)等八項。实驗結果表明:当改变寬度b及长度l时,对于延伸率的影响可用参数F~(2/l)/l (F为工作部分的截面积)来表示;对于强度的影响通常是很小的,只有当寬度很狭时,才引起显著的降低。当增加各項加工技术条件的誤差时,延伸率和强度均将下降(加工变形除外),其中延伸率下降得特别严重。对于这种现象,文內作了一定的分析。本文最后在实驗的基础上,提出了鋁管微型拉伸試样的合理的尺寸和技术条件。
In this work, an aluminum tube micro-tensile test specimen was used to measure the change of the tensile test result due to the change of its size and processing technical conditions. The changed dimensions and working conditions include: working width (b), length (l), surface finish, machining distortion, step misalignment (△ l), step non-squareness a) and thickness difference (△ f) and other eight items. The experimental results show that when the width b and the length l are changed, the influence on the elongation can be expressed by F 2 / l / F (F is the cross-sectional area of the working part); the influence on the strength is usually very small , Only when the width is very narrow, caused a significant decrease. When increasing the error of processing technology conditions, the elongation and strength will decline (except for processing deformation), of which the elongation rate is particularly serious. For this phenomenon, the text made a certain analysis. Finally, on the basis of the experiment, the reasonable size and technical conditions of the micro tensile test of the aluminum tube are proposed.