ELECTRON BEAM WELDING METHOD OF HIGH STRENGTH AND TOUGHNESS STEEL FOR IMPROVING IMPACT TOUGHNESS OF WELDING PART

摘要

PURPOSE: An electron beam welding method of high strength and toughness steel for improving impact toughness of a welding part is provided to improve safety at very low temperature in the welding part by absorbing impact energy efficiently in welding steel including 9% nickel. CONSTITUTION: A groove(3) is formed at 1/3 or 2/3 position in thickness of the steel material in case of butt welding of two test plates(1,1'). A nickel wire(2) is inserted to the circular, rhombic or rectangular groove, and fixed completely with electron beam welding. The content of nickel on a welding part(4) is distributed evenly, and impact toughness of the welding part is improved by generating remaining austenite over 6%. Acceleration voltage, beam current and welding velocity are adjusted according to the thickness of steel to insert the nickel wire completely. Impact toughness of the weld metal is improved at the very low temperature.