Weld shape design method capable of ensuring undermatching butt joint to bear load in light of strength of parent materials

Abstract

The invention relates to a weld shape design method capable of ensuring undermatching butt joint to bear load in light of strength of parent materials, solving the problem that the bearing capacity of the undermatching butt joint is lower than that of the overmatching weld joint. The method comprises the following main steps: computing the yield strength matching ratio muMMR of the undermatching joint, determining a weld shape scheme with minimum stress concentration, establishing a relation equation between the geometric parameters of a plate butt joint and the coefficients of stress concentration at weld toes and weld roots, computing the height h of weld reinforcement, the radius r of the weld toes and the total half width of cover passes and obtaining required weld geometric parametervalues. The method can ensure that the high-strength steel or ultra high-strength steel welding structure bearing tensile load can not only adopt undermatching joint mode which obviously reduces the occurrence rate of cold cracks but also ensure the static load bearing capacity of the undermatching butt joint not to be lower than that of the high-strength parent material and the fatigue strength to be obviously higher than the as-welded equalmatching joint. The method is suitable for X-shaped groove double-welded undermatching plate butt joints.

Description

technical field [0001] The invention relates to a welding seam shape design method, in particular to a welding seam shape design method which can make low-matching butt joints bear the strength of the base metal. Background technique [0002] With the wide application of high-strength steel in ships, submarines, pressure vessels, pressure pipelines, bridges, especially low-temperature vessels and cold marine structures, the problems of welding cracks, heat-affected zone embrittlement and softening of high-strength steel have become prominent. Among them, the damage caused by cold crack defects is the most serious, and it has become one of the main reasons for the early failure of welded structures. At the same time, the performance requirements of high-strength steel welded structures have been continuously increased due to harsh service conditions, and it is difficult to completely solve these problems by adjusting the chemical composition of steel. [0003] At present, th...

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Problems solved by technology

[0007] The purpose of the present invention is to provide a weld shape design method that can make low-matching butt joints bear the load according to the strength of the base metal, so as to solve the problem that the bearing capacity of low-matching butt joints is lower than that of matching joints above equal strength (that is, the bearing capacity of low-matching butt joints is lower than that of matching joints above equal strength The bearing capacity of the base metal is not equal or not equivalent)

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