MANUFACTURING METHOD OF ROLLED METAL WITH INCREASED RESISTANCE TO HYDROGEN AND HYDROSULPHURIC CRACKING Russian patent published in 2012 - IPC C21D8/02 C22C38/14 

FIELD: metallurgy.

SUBSTANCE: steel is molten and continuously poured into slabs; slabs are heated, pre-rolled and finally rolled and cooled in accelerated manner; at that, steel contains the following, wt %: C 0.02-0.10, Mn 0.5-1.5, Si 0.10-0.50, Nb 0.010-0.10, Al 0.01-0.05, Ti 0.005-0.05, N 0.003-0.012, S 0.002 and less, P 0.001-0.015, Ca 0.0002-0.005, Fe is the rest; at ratio of 0.03≤[C]×[Mn]≤0.12, slabs are heated to 1100-1300°C, pre-rolled with total deformation degree of 50-70% in the direction that is perpendicular to axis slab, and then, in temperature zone of 900-750°C in the direction that is longitudinal to slab axis with total deformation degree of 65-80%, cooled in accelerated manner in temperature zone of (Ar₃±30°C)-(600-400°C), first, to temperature of 600-500°C at the rate of 15-30 deg/s, and then, at the rate of 10-15 deg/s; after that, they are cooled slowly from temperature of 400°C to room temperature at the rate of 0.05-0.15 deg/s.

EFFECT: providing improved strength properties at simultaneous increase in cold resistance, low-temperature viscosity and resistance to hydrogen and hydrosulphuric cracking.

2 cl, 4 tbl, 1 ex