Abstract: The effect of 0. 75% ~ 1. 54% Mn on structure and properties of 4)16 mm hot-rolled coil of medium-carbon cold-heading steel (/% : 0.45C, 0. 22Si, 0. 75 ~ 1. 54Mn, 0. 007 ~ 0. 008P, 0. 003 ~ 0.004S) has been analyzed and studied. The end-rolling temperature of hot-rolling coil is 880 X., slow-cooling. Results show that with increasing manganese in steel from 0. 75% to 1. 54% , the tensile strength of coil increases from 661 MPa to 821 MPa, i. e. that increases by 160 MPa； the percentage of ferrite in structure of steel decreases from 49% ~53% to 9% 〜13%, the pearlite content in structure increases obviously and the pearlite lamellar spacing reduces from 0.5 μm to 0.25μm ； and the hardenability of steel improves significantly, that is the hardenability coefficient o£ steel increases from 3. 19 mm to 8. 81 mm.

摘要： 分析和研究了0.75%1.54%Mn对中碳冷镦钢Φ16 mm热轧盘条（/%:0.45C,0.22Si,0.751.54Mn,0.0070.008P,0.0030.004S）组织和性能的影响。盘条热轧的终轧温度为880℃,缓冷。结果表明,锰含量由0.75%增加到1.54%,盘条抗拉强度由661 MPa增加到821 MPa,增加了160 MPa;钢的组织中铁素体比例由49%~53%降低到9%~13%,珠光体含量显著增加,且珠光体片层间距由0.5μm降低到0.25.μm;淬透性能得到显著提高,淬透性系数由3.19 mm增加到8.81 mm。

关键词: 锰含量, 中碳冷镦钢, 热轧盘条, 组织, 力学性能, 淬透性