Abstract: The  dual  phase  steel  adding  Nb(0.19～0.21C,0.7～0.8Si,1.9~2. 1Mn,0.02～0.04Nb)and  no adding Nb(0. 17~0. 19C,0.4~0.6Si,1.7~1.9Mn)were melted by using a 25 kg vacuum induction furnace and hot rolled to 3.5 mm plate by two-high mill then cold rolled to1.0 mm and 1.36 mm sheet in laboratory. The cold sheet heated in salt bath furnace to740~820 ℃,slow cooled to 680 ℃ then fast cooled with cooling rate ≥50 ℃/s to 280 ℃ for 240 s,air cooling. Results showed that with increasing heating temperature,the martensite content in ferrite-martensite struc- ture increased;As heating temperature was 820 ℃,the tensile strength of C-Mn-Si dual phase steel no adding Nb was up to1050 MPa,and as adding Nb to furher fine grain of structure, the tensile strength of steel was up to 1200 MPa.

摘要： 用25kg真空感应炉冶炼的含Nb双相钢(%:0.19~0.21C、0.7~0.8Si、1.9~2.1Mn、0.02~0.04Nb) 和不含Nb双相钢(%:0.17~0.19C、0.4~0.6Si、1.7～1.9Mn),经实验室双辊轧机轧成3.5 mm板，再冷轧至1.0 mm和1.36 mm钢板。冷轧板通过盐浴炉加热至740～820℃缓冷至680℃,再以≥50 ℃/s冷至280 ℃保温240 s 空冷。结果表明，随加热温度提高，铁素体-马氏体组织中的马氏体量增加；当加热温度为820 ℃时C-Mn-Si双相钢 抗拉强度可达1050 MPa,加Nb后由于晶粒进一步细化，820 ℃加热时，其抗拉强度可达1200 MPa。