JPS54125148A - Welded structure of hardened steel - Google Patents

Abstract

PURPOSE: To prevent the weld zone from generation of cracks, etc., and to make possible the welding of the structure, by applying the electron beam welding to the hardenable steels before the hardening treatment, and by applying the hardening treatment to this welded structure.

CONSTITUTION: In case of welding of previously machined and ground valve sheath 2 and the nozzle tip 1, like as the fuel injection valve, etc., of the Diesel engine for instance, these two parts 1, 2, are made of untreated hardenable steel, and are welded by electron beam; after that, the hardening treatment is applied to this welded structure depending on the carburizing and quenching, or the nitriding treatment, etc. Hereby, the damage of durability, generation of cracks, etc., due to the influence of the residual stress caused by welding can be prevented; besides, the generation of defects due to the difference in the components of the parent metal and the deposited metal, which happens in the conventional method can also be prevented. The heat treatment effect makes thus manufactured structure to be equivalent to the structure which is manufactured originally as a monolithic structure. According to this method, the welding for obtaining superior structure becomes possible.

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