METHOD TO PRODUCE THICK-SHEET LOW-ALLOYED STRIP Russian patent published in 2012 - IPC C21D8/02 C22C38/58 

FIELD: metallurgy.

SUBSTANCE: billet is produced from steel containing the following, wt %: C 0.03-0.08, Mn 1.6-2.2, Si 0.12-0.40, Ni 0.28-0.55, Mo 0.20-0.45, Cr 0.01-0.1, Cu 0.1-0.4, Nb 0.03-0.07, Ti 0.01-0.04, V 0.01-0.06, Al 0.01-0.05; balance - iron and admixtures, with content of each admixture element of less than 0.05%, at the same time the quantity of sulfide non-metal inclusions does not exceed 1.5 points, and the quantity of other non-metal inclusions does not exceed 3 points. Billets are heated to 1170-1200°C, exposed to breaking down, then cooled down to 820-850°C, finish rolling is completed at 770-820°C, and a strip is quickly cooled down to the temperature defined depending on thickness of the finished strip, based on the ratio T=(250+20000/S²)±40°C, then the strip is straightened, when in the area of the first bending the amplitude of deviation from the strip plane is determined depending on the thickness of the finished strip, based on the ratio δ₁'=(1600/S²)±4 mm, besides, for each subsequent bending the amplitude of deviation is reduced.

EFFECT: higher limit of strength and fluidity with preservation of plastic properties at a level making it possible to form pipes from a strip.

2 cl, 1 ex