高强高塑马氏体汽车钢的快速回火调控

Rapid tempering control of high-strength and high-plasticity martensitic automotive steel

在追求汽车工业中使用的马氏体钢的高强度与高塑性的平衡时,研究提出了一种新的快速回火工艺。通过对新设计的中碳马氏体汽车钢进行快速回火处理,并与传统回火工艺进行对比,探讨了该工艺对钢材组织和性能的影响。研究采用了电子万能试验机、数字图像相关法、X射线衍射、电子背散射衍射和场发射扫描电子显微镜等先进技术,揭示了快速回火工艺通过维持高位错密度和细化析出碳化物来保持马氏体的高强度。实验结果显示,该工艺在不牺牲塑性的前提下,成功提高了材料的抗拉强度和屈服强度,在400℃快速回火时分别达到1616和1466 MPa,比传统工艺分别提高了10.2%和12.5%,同时保持了超过10%的伸长率。当回火温度为300℃时,马氏体汽车钢在保持高伸长率的同时,抗拉强度接近2000 MPa。这一发现不仅为高强度马氏体汽车钢的制备提供了新思路,也为未来汽车工业的材料选择提供了重要参考。

In the demand for a balance between high strength and high ductility of martensitic steel for automotive application,a new rapid tempering process was proposed.The research involved rapid tempering of newly designed medium-carbon martensitic automotive steel and comparison with that by conventional tempering approach to explore the impact on the steel's microstructure and properties.Employing the techniques and equipment such as tensile testing machines,digital image correlation methods,X-ray diffraction,electron backscatter diffraction,and field emission scanning electron microscopy,the study revealed that the rapidly tempered specimen maintained high dislocation density and refined precipitated carbides,thereby preserving the martensite's high strength.The results showed that the new processing successfully enhanced the material's tensile strength and yield strength to 1616 and 1466MPa,respectively,at a rapid tempering temperature of 400℃,leading to an increase of 10.2%and 12.5%over the conventional process while maintaining an elongation of over 10%.When tempered at 300℃,the martensitic automotive steel maintained a high elongation with a tensile strength near 2000MPa.These findings not only offer a new perspective on the preparation of highstrength martensitic automotive steel but also serve as a significant reference for material selection in future automotive industries.