| 摘要 |
FIELD: metallurgy. ^ SUBSTANCE: there is melted steel containing wt %: 0.35 ëñ C ëñ 1.05, 15 ëñ Mn ëñ 26, Si ëñ 3, Al ëñ 0.050, S ëñ 0.030, P ëñ 0.080, N ëñ 0.1, at least one metal element X chosen from vanadium, titanium, niobium, molybdenum and chromium at amount: 0.050 ëñ V ëñ 0.50, 0.040 ëñ Ti ëñ 0.50, 0.070 ëñ Nb ëñ 0.50, 0.14 ëñ Mo ëñ 2, 0.070 ëñ Cr ëñ 2, and, not necessary, one or several elements chosen from 0.0005 ëñ B ëñ 0.010, Ni ëñ 2, Cu ëñ 5, iron and unavoidable impurities the rest. Semi-finished product cast out of this steel is further heated to temperature 1100 -1300 C and hot rolled to temperature of finish rolling of 890C or above. There is produced sheet successively wound into a coil at temperature below 580C. The coil is at least once cold rolled and subjected to at least one operation of annealing at velocity of heating Vh from 2 to 10C/sec at temperature Ts from 700 to 870C from 30 to 180 sec and at rate of cooling from 10 to 50C/sec. Coating out of Zn or alloy Zn-Y is applied on the sheet, where Y corresponds to one or more from Ni, Cr, Mg. The sheet is subjected to at least one conditioning in atmosphere of pure nitrogen or argon with a dew point below -30C at temperature 0 within ranges from 250 to 900C during time t. Also, temperature and time meet the ratio: (C) Ln(t(sec)) ëÑ 2200. ^ EFFECT: manufactured steel sheets possess high durability and plasticity which reduces weight and increases safety owing to absorption of power at impact. ^ 39 cl, 4 dwg, 4 tbl, 1 ex |
