ROUND ROLLED PRODUCTS FROM STRUCTURAL ALLOYED STEELS MANUFACTURING METHOD FOR THE FASTENERS COLD DIE FORGING Russian patent published in 2019 - IPC C21D8/06 C22C38/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, specifically to the high-quality rolled steel from alloyed steels production methods for the fasteners manufacturing by the cold die forging. Performing the workpiece heating to the temperature of 1,080–1,200 °C, hot rolling with rolling end temperature in the range of 900–1,050 °C and regulated cooling, at that, cooling after rolling is performed with a rate of 0.1–5 °C/s to T_cool=541.1–144.3[C] – 94.5[Si] – 24.6[Mn] – 9.6[Cr] – 4.84[Ni] – 52.0[Mo]±20 °C, and the final cooling is performed at the arbitrary rate. Cooled rolled products is subjected to the spheroidizing annealing at T_ann=688.8 + 20.4[Si] – 13.5[Mn] + 17.7[Cr] – 13.8[Ni] + 6.5[Mo] ± 10 °C. Rolled products are obtained from the steel containing, wt. %: carbon 0.09–0.47, silicon 0.17–0.40, manganese 0.30–0.94, chromium 0.4–1.35, nickel up to 0.8, molybdenum 0.1–0.3, sulfur is not more than 0.045, phosphorus is not more than 0.035, iron and inevitable impurities are the rest being.

EFFECT: increase in the rolled products mechanical properties.

1 cl, 3 tbl, 1 ex