Welding structure with excellent resistance to brittle crack propagation

Abstract

A welded structure wherein steel plates having at least partial regions with a brittle crack arrest property Kca of 4000N / mm 1.5 or more are butt welded together so as to form a steel plate welded joint, wherein at least one location of the steel plate welded joint is provided with a crack control part which diverts a brittle crack which has occurred at the steel plate welded joint to a steel plate base metal side, outer edges of an insert member which forms the crack control part are formed to extend in the longitudinal direction of the steel plate welded joint from a weld metal zone of the steel plate welded joint while slanted by 15° to 50° with respect to the longitudinal direction of the steel plate welded joint, and a horizontal width direction end of the insert member is made to face a region of the steel plate where the Kca is 4000N / mm 1.5 or more, whereby even if a brittle crack occurs in the welded joint, the brittle crack can be kept from propagating through the weld joint and base metal.

Description

technical field [0001] The present invention relates to a welded structure excellent in brittle crack propagation resistance which controls and suppresses the propagation of brittle cracks when brittle cracks occur in welded joints. [0002] In particular, even when a brittle crack occurs in a welded joint of a welded structure welded by using a thick steel plate, the propagation of the brittle crack can be controlled and suppressed to improve safety, and the brittle crack propagation resistance is excellent. welded structure. Background technique [0003] In recent years, welded structures represented by welded structures for ships such as large container ships and bulk carriers, architectural structures, and civil engineering steel structures have been required to have high safety against damage such as brittle cracks. In particular, the increase in the size of container ships is very obvious. For example, large container ships of 6,000 TEU or more can be manufactured, an...

AI Technical Summary

Problems solved by technology

However, in the welded structure of Patent Document 1, it is effective when the fracture toughness of the base material is very excellent, but when the fracture toughness of the base material is insufficient, brittle cracks deviated to the base metal side Longer propagation, as the strength of the structure may be significantly reduced

In addition, there are also problems in that the volume of the refilled welded part becomes larger, the process time is prolonged, and the manufacturing cost is also increased.

However, in the case where the welded structure described in Patent Document 2 is applied to a large building, for example, a brittle crack propagating in the welded joint propagates in the welded joint where the insert material is welded to the steel plate and enters into the insert. material, propagate as it is inside the inserted material, and then possibly again in the welded seam

On the other hand, when the brittle cracks propagating in the welded joint deviate toward the base metal side of the insert material and the welded joint position of the insert material welded to the steel plate, there is also a concern that there may be the following problem as above: When the fracture toughness of the material is not sufficient, brittle cracks propagate for a long time, and the strength as a welded structure is significantly reduced

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