METHOD FOR PRODUCTION OF HOT-ROLLED THICK SHEETS FROM LOW-ALLOY STEEL FOR NUCLEAR AND POWER ENGINEERING

摘要

FIELD: metallurgy.;SUBSTANCE: invention relates to metallurgy and can be used for making large-size products of nuclear and power engineering. For production of rolled stock with thickness from 80 to 150 mm with guarantee of standard properties after normalization with tempering of continuously cast workpieces with thickness of not less than 315 mm, austenisation of workpieces is carried out at a temperature of 1,200–1,215 °C, rough rolling is started at a temperature not lower than 950 °C and is performed to roll thickness not less than 1.3 thickness of finished sheet with relative reduction per pass of not less than 10 %, finish rolling is started at temperature of 115±25 °C above point of Ar₃ and ends at 5–15 °C above temperature of beginning of finish rolling, then sheets are subjected to slow cooling in air in a stack. Continuous cast workpieces are made from steel containing, wt%: 0.09–0.12 C; 0.70–0.80 Si; 1.55–1.70 Mn; 0.20–0.30 Cr; 0.20–0.30 Ni; Cu ≤ 0.10; 0.015–0.030 Ti; N ≤ 0.008; 0.02–0,05 Al; S ≤ 0.002; P ≤ 0.010; Fe and impurities – balance.;EFFECT: structure of finished sheet is represented by ferrite and sorbite-like pearlite in volume ratio of not less than 30 % and is characterised by high homogeneity, wherein grains, different from prevailing number more than 1 occupy an area of not more than 10 %.;1 cl, 4 tbl