A Method for Determining the Anisotropy Parameters of Pipes

Abstract

The invention relates to a method for determining the anisotropy parameter of a pipe, which belongs to the field of pipe performance testing. The method: 1. Cut the slit sample along the pipe axis, conduct uniaxial tensile test, and obtain the yield stress of the pipe axial direction; 2. Conduct two-way loading experiments on the pipe to be tested, the loading path is linear, and record the stress Measure the strain increment ratio under the corresponding loading conditions; 3. Establish the relationship between the stress ratio, the strain increment ratio and the yield stress in each direction; establish the relationship between the stress ratio, the strain increment ratio and the thickness anisotropy coefficient in each direction; 5. , Substitute the stress ratio and strain increment ratio in step 2 into the relationship formulas established in 3 and 4 respectively, and obtain the anisotropic parameters by solving the equations: hoop yield stress, double isotensive yield stress, axial thickness Anisotropy coefficient, circumferential thickness anisotropy coefficient. The method avoids the plastic deformation of the pipe before the test and the influence of the pre-deformation on the anisotropy parameters, and the determined anisotropy parameters are more accurate.

Description

technical field [0001] The invention belongs to the field of performance testing of pipes, and in particular relates to a method for determining anisotropy parameters of pipes. Background technique [0002] Tubes are often used in the forming of tubular parts. In the production and preparation of pipes, due to the severe plastic deformation of the material, the grain structure and texture shape inside the material often change and have a certain directionality, so that the pipe has the characteristics of anisotropy. The main manifestations of anisotropy are different yield stress and thickness anisotropy coefficients along all directions of the pipe. The anisotropic characteristics of the pipe in different directions directly affect the yield behavior and plastic deformation behavior of the pipe, which will affect the deformation behavior of the pipe during the actual deformation process. Therefore, in order to accurately describe the characteristics of the pipe and formul...

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Problems solved by technology

[0005] The present invention proposes a method for determining the anisotropy parameters of pipes to solve the problem that the existing experimental testing methods cannot or cannot accurately measure the characteristic parameters of pipe anisotropy

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