ALLOYING METHOD OF INNER SURFACE OF HOT-ROLLED PIPES Russian patent published in 2009 - IPC B23K26/34 C23C4/12 B21B23/00 

FIELD: machine building.

SUBSTANCE: invention relates to machine building field, particularly to pipe rolling. Method includes pre-heating of treated surface, following treatment by focused laser beam up to melting of surface coating and introduction into melt of alloy additions. Invention provides in the capacity of pre-heating of pipe to use standard intermediate heating of tubular billet at its rolling, after the final redistribution of tubular billet to limit access of oxygen into inner cavity of pipe, following treatment by laser beam to implemented at pipe temperature not lower than 850 degrees, and into content of alloying mixture to add deoxidisers.

EFFECT: increase of corrosion resistance of hot-rolled pipes generally and tubing pipes particularly.