Method for determining constitutive parameters of butt welded pipe welding seam in biaxial stress state

Abstract

The invention relates to a method for determining constitutive parameters of a butt welded pipe welding seam in the biaxial stress state, which comprises the following steps of: determining the constitutive parameters of the parent metal in the uniaxial stress state, thereby determining the range of the parent metal strength factor K<sim> in the perforated sample tensile finite element analogy, and the range of the hardening index n<sim>; and by determining the variation ranges of the strength factor and the hardening index, obtaining the relationship between different constitutive parameter combinations (K<sim>, n<sim>) and the combinations (F<sim>, Delta l<sim>) of tensile force and gauge length elongation, and establishing a recessive mapping relationship between the combination (F, Delta l) of tensile force and gauge length elongation and the constitutive parameter combination (K, n), thereby obtaining the constitutive parameters of the welding seam in the biaxial stress state. The method induces the planar biaxial tension stress state, which is more approximate to the true stress state of pipe deformation, in the uniaxial tension process of a perforated sample, can be used for accurately and efficiently determining the constitutive parameters of the welding seam ductility of a butt welded pipe, and is beneficial to enhancing the forming quality and the forming limit of the welded pipe.

Description

technical field [0001] The invention relates to the field of plastic forming of straight seam welded pipes, in particular to a method for determining the constitutive parameters of the weld seams of the straight seam welded pipes under the bidirectional stress state, and the technology can also be extended to the determination of the constitutive parameters of the weld seams of tailor welded blanks. Background technique [0002] Due to the characteristics of low cost, short cycle time and toughness, the bending parts of longitudinal welded pipes have been widely used in the automobile industry. The main difference between the welded pipe and the seamless pipe lies in the significant difference between the properties of the weld and the base metal, and the influence on the plastic forming performance is mainly reflected in the significant difference between the strength coefficient K and the hardening index n in the constitutive parameters of the weld and the base metal. The ...

AI Technical Summary

Problems solved by technology

[0006] In order to overcome the problem that the existing technology cannot obtain the constitutive parameters of welded pipe welds under the state of bidirectional stress, the present invention proposes a method for determining the constitutive parameters of welded seams of straight seam welded pipes under the state of bidirectional stress

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