ELECTRIC ARC WELDING PROCESS OF VERTICAL SEAM BY UP-DOWN METHOD WITH USE OF COATED ELECTRODE Russian patent published in 2006 - IPC B23K9/14 

FIELD: processes for electric arc welding by means of coated electrode, namely welding vertical seam by up-down method.

SUBSTANCE: process comprises steps of electrodynamic action upon metallic and slag baths flowing inside coating overhang on end of electrode. Such action is realized due to increasing welding current from time moment (t1) of starting short circuiting caused by flowing in of metallic or slag bath inside overhang of coating on end of electrode. At time moment t2 of arc voltage drop lower than 10 - 14 V welding current is increased by 1.5 times in comparison with its predetermined value. If for time interval (t2 - t3) more than 30 ms short circuiting is not prevented that is bridge of melt metal is not broken, welding current is increased in addition by 1.75 - 2.0 times. After time moment t4 when bridge is broken electric arc voltage increases. At time moment t5 of restoring electric arc discharge, welding current achieves predetermined value.

EFFECT: improved quality of welded seam due to elimination of long-time flowing-in of metallic and slag baths inside overhang of coating on end of electrode.

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