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 1 616 and 1 466 MPa,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 2 000 MPa.These findings not only offer a new perspective on the preparation of high-strength martensitic automotive steel but also serve as a significant reference for material selection in future automotive industries.
维普
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