METHOD OF HIDDEN ARC WELDING OF STEEL MATERIAL USING MULTIPLE ELECTRODES Russian patent published in 2013 - IPC B23K9/18 

FIELD: process engineering.

SUBSTANCE: invention relates to hidden arc welding using multiple electrodes for production of large-diameter steel tubes from 10-50 mm-thick billets. In welding, three and more electrodes are used to form half the molten pool. DC power supply is used for feed current to first electrode. Welding by first electrode is performed at current density of 250 A/mm² and higher, preferably, at wire diameter of 3.2 mm and smaller while welding current makes 1000 A and higher. Welding by second electrode is performed at current density of 150 A/mm² and higher, at welding current of 600 A and higher. One of spacings between electrodes on steel surface makes 23 mm and larger while remaining spacing makes 20 mm and smaller.

EFFECT: higher efficiency.

10 cl, 12 dwg, 2 ex, 8 tbl