welded structure

Abstract

A welded structure provided with a fillet-welded joint obtained by bringing an end surface of a bonding member into contact with the surface of a bonded member having a plate thickness equal to or greater than 50 mm and bonding the bonding member and the bonded member by fillet welding, the weld leg length and / or the welding width of the fillet-welded joint being equal to or less than 16 mm. The welded structure has, on the plane at which the end surface of the bonding member and the surface of the bonded member are brought into contact with each other, a non-welded section at which the joint cross-section is no less than 95% of the plate thickness t of the bonding member. The fillet welding is adjusted so that the fillet welding metal is such that the relationship between the fracture appearance transition temperature vTrs(°C) of the fillet welding metal and the plate thickness tf of the bonded member satisfies the expression vTrs<=-1.5tf+70, and / or the relationship between the absorption energy vE-20(J) at a test temperature of -20°C and the plate thickness tf of the bonded member satisfies vE-20(J)>=2.75tf(mm)-105; whereby propagation of brittle cracking generated from the bonded member having a plate thickness equal to or greater than 50 mm and having a butt-welded joint section is arrested at the fillet-welded metal section.

Description

technical field [0001] The present invention relates to welded steel structures such as large container ships and bulk carriers (bulk carriers) constructed by welding using thick steel plates, and particularly relates to a structure capable of suppressing the propagation of brittle cracks generated from thick steel plate base materials or welded joints. It is a welded structure that stops before the large-scale destruction of the object and has excellent brittle crack propagation stop characteristics. Background technique [0002] For example, container ships and bulk carriers have a structure in which there are fewer partition walls in the cabin and a large opening in the upper part of the ship, unlike oil tankers, for example, in order to increase loading capacity and improve loading and unloading efficiency. Therefore, in container ships and bulk carriers, it is particularly necessary to make the shell plating high-strength or thick-walled. [0003] In addition, in recen...

AI Technical Summary

Problems solved by technology

This means that it cannot be asserted that there is no possibility of brittle failure propagating in a straight line along the weld

[0008] However, there are many practical results in which ships built by applying the same welding as the welding applied in Non-Patent Document 1 to steel plates with a plate thickness of less than 50 mm sail without abnormality, and it has also been recognized that steel plate base materials with good toughness (shipbuilding Class E steels, etc.) maintain sufficient ability to stop brittle cracks, so the brittle crack propagation stop characteristics of welded parts of shipbuilding steels are not particularly required in ship classification rules, etc.

Therefore, securing the safety of the hull structure using high-strength thick steel plates with a plate thickness of 50 mm or more has become a major issue

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