METHOD FOR COMPOSITION-TYPE CONTACT WELDING OF SCRATCH-RESISTANT COATINGS TO PARTS OF END SEALINGS OF PUMPING AGGREGATES IN MAIN PIPELINES Russian patent published in 2008 - IPC B23K11/00 B23P6/00 

FIELD: manufacture and restoration of worn sleeves and rings of end sealings of pumping aggregates of main pipelines for pipeline transporting of oil and gas.

SUBSTANCE: method comprises steps of preliminarily heating parts of end sealing till temperature of phase conversion; performing electric contact welding on by means of electric current pulses of belt of quick cutting steel with powder material of hard alloys deposited on it; placing belt in such a way that to turn powder material to protected surface of part; realizing welding on for 5 cycles at intervals 2 - 3 c while changing electric current pulse value by 10% relative to its initial value and changing pressure value for forcing belt to protected part by 25% relative to its initial value in each cycle; selecting initial value of electric current pulse of contact welding and initial value of forcing pressure to part depending upon material and thickness of coating and part. Invention provides improved scratch- and wear-resistance of surface layer of sleeves and rings of large size with diameters up to 160 mm and protection layers up to 0.1 - 1.5 mm.

EFFECT: enhanced scratch resistance and wear resistance of surface layers of sleeves and rings, elimination of destruction of hard alloy particles.

1 dwg, 1 ex