HIGH-STRENGTH LOW-TEMPERATURE WELDED REINFORCING ROD Russian patent published in 2022 - IPC C22C38/58 C22C38/50 C22C38/48 C21D8/08 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, namely to the production of continuous cast high-strength welded steel reinforcing rods with a diameter of 12 to 36 mm, used as working reinforcement of reinforced concrete structures, as well as structures operating at low temperatures up to minus 170°C. The rod is made of steel containing components at the following ratio, wt. %: carbon no more than 0.10, manganese 0.60-1.80, silicon 0.05-0.60, nickel 0.50-1.30, copper no more than 0.40, chromium no more than 0.40, vanadium no more than 0.03, niobium no more than 0.03, molybdenum no more than 0.07, if necessary, titanium no more than 0.03, arsenic no more than 0.01 and nitrogen no more than 0.01, the rest is iron and unavoidable impurities. The rod has a carbon equivalent value calculated by the expression Ceq=C+Mn/6+(Cr+V+Mo)/5+(Cu+Ni)/15, which is no more than 0.52, a microstructure consisting of tempered martensite, lower and upper bainite. The reinforcing rod has improved performance and mechanical properties, namely the ratio of b/f is no less than 1.15, the value r≥14%, while at a temperature of minus 168°C the reinforcing rod has a flow point f no less than 575 MPa, relative uniform elongation max no less than 3%, the coefficient of sensitivity to notches KNSR at least 1, where r is relative uniform elongation, %, b is rupture strength, MPa, f is flow point, MPa.

EFFECT: expansion of the range of solutions for the production of high-strength welded steel reinforcing rods.

4 cl, 3 tbl