时效温度对HSLA100钢组织与性能的影响
Effect of Aging Temperature on Microstructure and Properties of HSLA100 Steel
严 翔1,2, 陈 玮2, 刘武群2, 周桂峰1,2
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作者单位：1. 武汉科技大学 材料与冶金学院, 湖北 武汉 430081; 2. 武汉钢铁(集团) 公司 研究院, 湖北 武汉 430080
中文关键字：HSLA100钢； 时效； 贝氏体； 沉淀析出
英文关键字：HSLA100 steel; aging; bainite; precipitation
中文摘要：研究了HSLA100钢轧态及时效过程中组织与力学性能的变化。结果表明：HSLA100钢轧态组织为高密度位错的板条贝氏体， 板条间分布着少量M-A岛。经450 ℃时效处理后，大量球状ε-Cu相沉淀析出，此时钢板屈服和抗拉强度最高， 而-40 ℃冲击功最低。在450～720 ℃时效时，随时效温度升高，高密度板条贝氏体发生回复，ε-Cu相粗化成短棒状， 屈服强度连续下降，但在650 ℃时效时仍达到760 MPa的较高水平；抗拉强度在650 ℃时达到最低值后小幅上升；-40 ℃冲击功持续升高至700 ℃附近达到峰值。钢质纯净度是影响HSLA100钢低温韧性的一个主要因素，虽然通过升高时效温度可在一定程度上提高钢的低温冲击韧度，但增幅有限。
英文摘要：The variation of microstructure and mechanical properties of HSLA100 plates as-rolled and aged were investigated. The results show that the matrix microstructure of HSLA100 steel is lath bainite with high dislocation density and some M-A island among them. Substantial improvement in strength occurs at the expense of impact toughness on aging by 450 ℃ owing to profuse ε-Cu precipitation in the matrix. With the increase of aging temperature between 450 ℃ and 720 ℃, the partially recovered matrix and the coarsened ε-Cu precipitates presumably improve the notch toughness at -40 ℃ considerably, reaching peak values at 700 ℃ aging, and reducing the yield strength continuously, dropping to 760 MPa at 650 ℃ aging, and reducing tensile strength considerably, reaching valley value at 650 ℃ aging. The results reveal that the purity of steel is one of major elements on low-temperature flexibility, though notch toughness can be improved considerably by increasing aging temperature.