| 摘要 |
PURPOSE:To improve the safety against brittle fracture by using a ferritic welding wire contg. specific weight % of Ni and maintaining the min. width of the weld metal in the crack propagation direction at a prescribed size or above. CONSTITUTION:A groove is formed to low temp. steel materials 1, 2 and a weld metal 3 is deposited thereto by using the ferritic welding rod contg. 8-13% Ni. The arc welding is executed in such a manner that the min. width l of the weld metal 3 in the direction perpendicular to the plate thickness, i.e., the crack propagation direction is maintained at >=10mm in the welded joint part. Since the ferritic wire contains 8-13% Ni component, the required toughness is obtd. with the weld metal 3 and the deterioration of the strength and crack propagation characteristic thereof is prevented. The brittle crack generated in the welded structure is stopped within the joint by the above-mentioned method, by which the safety against brittle fracture is improved.
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