Method for measuring yield strength of non-planar structure material

Abstract

The invention relates to a method for measuring yield strength of a non-planar structure material. The method comprises: 1, manufacturing a tension specimen, clamping the specimen in a tension testing machine, clamping an extensometer on the tension specimen, and setting the extensometer to zero; 2, directly loading on the tension specimen to carry out a tension test to obtain a complete tension test curve; and 3, selecting two points from a proportion extension section as base points, adopting the two points to obtain a straight line, adopting an intersection point of the straight line and a abscissa as an origin, adopting the origin as a benchmark to rightward find a strain point of 0.5% specimen gauge length on a strain shaft, wherein a load value corresponding to the strain point is a conditional yield load corresponding to 0.5% strain, and the yield strength of the material can be measured according to the yield load and the specimen size. With the method of the present invention, influence on measurement of the yield strength Rt0.5 of the material by roughness of the specimen can be eliminated, and the unique yield strength Rt0.5 value can be accurately, reliably and repeatedly measured.

Description

technical field [0001] The invention relates to the technical field of material testing, in particular to a method for measuring the yield strength of non-planar structural materials. Background technique [0002] The yield strength of the material (such as R t0.5 ) is one of the most important indicators to characterize the mechanical properties of materials. For non-planar structural materials (such as steel pipes), in the preparation of tensile specimens, the specimens must be flattened by slow loading, so that the specimens obtained cannot be in an ideal plane. During the test, after clamping the extensometer, operate according to the conventional tensile test method, and obtain the strain-load curve measurement as figure 1 shown. The starting segment in the curve (similar to figure 2 In paragraph a), because the sample is not completely flattened (it is bent to a certain extent), a large strain is generated under a small load. At this time, if the directly obtaine...

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Problems solved by technology

In addition, because this operation does not clearly specify the value and degree of preload, the yield strength R of the material is measured in this way. t0.5 It will be affected by the operating habits of different operators, and the actual value obtained may be the stress value corresponding to the gauge length greater than 0.5% strain in the gauge range, rather than the desired R t0.5

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