WELDED BY ELECTRICAL RESISTANCE WELDING STEEL PIPE, HAVING EXCELLENT RESISTANCE TO HYDROGEN INDUCED CRACKING (HIC) AND LOW-TEMPERATURE SHOCK VISCOSITY OF JOINT WELD RECEIVED BY ELECTRIC CONTACT WELDING AND METHOD OF ITS MANUFACTURE Russian patent published in 2017 - IPC C22C38/06 C22C38/18 B21C37/08 B21D5/12 C21D9/08 C21D9/50 

FIELD: metallurgy.

SUBSTANCE: steel has the chemical composition, containing in wt %, C: from 0.03 to 0.59, Si: from 0.10 to 0.50, Mn: from 0.60 to 2.10, Al: from 0.01 to 0.35, Ca: from 0.0001 to 0.0040, Cr: from 0.01 to 1.09, wherein the Si content and the Mn content satisfy to the weight ratio Mn/Si ranging from 6.0 to 9.0, and the rest is Fe and the unavoidable impurities. In the joint weld, the total amount of silicon, manganese, aluminium, calcium and chromium in inclusions with the equivalent circle diameter of 8 mcm or more is not more than 16 ppm wt %, related on the total weight of the joint weld 2 mm, including the base, containing the iron and unavoidable impurities.

EFFECT: increase of the tensile strength, resistance of the joint weld to hydrogen induced cracking and low-temperature shock viscosity at Charpy test.

13 cl, 4 dwg, 3 tbl