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

FIELD: metallurgy.

SUBSTANCE: billet produced from steel containing the following, wt %: C=0.03-0.10; Mn-1.6-2.0; Si=0.15-0.35; Ni=0.30-0.60; Mo=0.25-0.45; Cr≤0.15; Cu=0.1-0.4; Nb=0.03-0.07; Ti≤0.03; V≤0.035; balance - iron and admixtures, with content of each admixture element of less than 0.05%, having a crack resistance ratio Rsm of less than 0.25%, the size of actual ferrite grain that does not exceed 15 mcm, is exposed to breaking down and finish rolling. Breaking down is carried out at the temperature of at least 950°C with reduction rate per pass of at least 10%, excluding the last pass, to the thickness of an intermediate blank of 80-140 mm, then cooled down to 820-850°C. After finish rolling the strip is quickly cooled down to 560-640°C, straightening is carried out at the temperature of at least 350°C, then moderated cooldown is carried out to the temperature of not higher than 100°C.

EFFECT: improved strength and plastic properties of a strip.

3 cl, 1 ex