Designing method for realizing equal load-carrying of tension-loaded butt joint with central crack on welding line, and application of K factor

Abstract

The invention discloses a designing method for realizing the equal load-carrying of a tension-loaded butt joint with a central crack on a welding line, and the application of a K factor, which belong to the field of welding and aim to solve the problem that the load-carrying capacity of the tension-loaded butt joint with the central crack is lower than that of a parent metal. If the parent metal of the tension-loaded joint with the central crack on the welding line also has a crack, the designing method comprises the following steps of: determining equal load-carrying conditions, and the fracture toughness of a weld metal and the parent metal; calculating a stress intensity factor of a parent metal area and the stress intensity factor of a welding line area meeting equal load-carrying; calculating a stress intensity factor formula; and obtaining geometrical parameter values of the welding line. If the parent metal of the tension-loaded joint with the central crack on the welding line is free from defect, the designing method comprises the following steps of: determining the equal load-carrying conditions, and the tensile strength of the parent metal; calculating the stress intensity factor formula; determining a critical stress relational expression, and the fracture toughness of the weld metal; and obtaining the geometrical parameter values of the welding line. The stress intensity factor of the welding line area is applied to the calculation of critical crack size, critical stress and remaining service life of the tension-loaded joint with the central crack. The method and the application are applied to plate butt joints welded on both sides.

Description

technical field [0001] The present invention relates to a design method of a butt joint subjected to tensile load and the application of K factor, in particular to a design method of butt joint which can make a butt joint with a central crack in the weld be subjected to tensile load according to the bearing capacity of the parent material and The invention relates to an application method of a stress intensity factor in a weld zone, belonging to the technical field of welding. Background technique [0002] As a special connection method, welded structures are widely used in civil and military production design, etc., especially for the current lightweight requirements, high-strength materials are widely used. For welded joints, due to the role of the welding process, the properties of the material have changed greatly, and the conventional mechanical properties and fracture toughness of the joint local area have been greatly reduced. Welding defects are inevitable, especial...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a design method and the application of K factor for realizing equal load bearing of butt joints with central cracks in welds and tensile loads, so as to solve the problem that the bearing capacity of butt joints with central cracks in welds is lower than that of parent joints. material bearing capacity, and the joint is prone to the problem of low stress brittle fracture; the present invention also proposes the stress intensity factor expression (stress intensity factor of the weld zone) according to the stress intensity factor (stress intensity factor of the weld zone) containing the central crack in the weld zone to obtain the weld zone Important parameters such as the critical crack size, critical stress, and remaining life under fatigue loads of butt joints with central cracks under tensile loads solve the problem of evaluating the reliability of butt joints with central cracks in service

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