METHOD OF MOUNTING PIPE LINE FOR TRANSPORTATION OF AGGRESSIVE MEDIA Russian patent published in 1999 - IPC

FIELD: welding technological; welding pipes covered with corrosion-resistant nonmetallic coats and used for transportation of aggressive media. SUBSTANCE: metal ferrules, no less than 30 mm in length are welded to ends of pipes made from carbon and low-alloyed steel. Ferrules consists of two layers: one layer is made from carbon or low-alloyed steel and at least one layer is made from corrosion-resistant steel at content of chromium no less than 8%. Nonmetallic corrosion-resistant coat is applied on surfaces of blanks without applying coat on sections of ferrules adjoining the joint. Thickness of corrosion-resistant layer of ferrule is no less than 5% of total thickness of its wall. Then pipes are welded together. At least root weld of joint is made by filler material from corrosion-resistant steel at content of chromium corresponding to that of corrosion-resistant layer of ferrule. EFFECT: enhanced corrosion resistance of welds; reduced consumption of alloy materials at retained weldability. 2 cl, 1 dwg