LOW-BACKPRESSURE PENETRATION ELECTRIC ARC WELDING APPARATUS AND METHOD

摘要

A low-backpressure penetration electric arc welding apparatus. Air extraction of a central negative-pressure cavity (111) of a low-backpressure protection apparatus (11) is performed by means of an air extracting apparatus (4), so that a tail flame of a penetration electric arc located in the central negative-pressure cavity and a back side of a keyhole molten pool are in a negative-pressure state of an argon atmosphere, and a pressure gradient pointing from the front side to the back side of the molten pool is formed on the keyhole molten pool, the stiffness and the electric arc stability of the penetrating electric arc on the front side of the molten pool are further enhanced, and the penetrating capability of the penetrating electric arc is improved on the premise of not changing the front side stress distribution and the temperature gradient of the keyhole molten pool. Also disclosed is a low-backpressure penetration electric arc welding method. The welding apparatus greatly increases the weldable thickness of a conventional penetrating electric arc welding process, and the welding line back side shaping of penetration welding is improved by maintaining the negative-pressure state on the back side of the molten pool.