Effect of over-aging temperature on microstructure and properties of DP1180 steel under continuous annealing process

doi:10.13251/j.issn.0254-6051.2023.01.026

Abstract

Abstract: Microstructure and mechanical properties of the DP1180 steel were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and room temperature tensile techniques. The results show that microstructure of cold-rolled annealed steel is mainly composed of ferrite (F), martensite (M) and a small amount of bainite. When over-aged at 230 ℃, the martensite is mainly lath-like, the ferrite is polygonal, and the content of granular bainite is less. With the increase of over-aging temperature, the content of lath-like martensite decreases, granular bainite increases and carbides increase obviously. With the increase of over-aging temperature, the tensile strength decreases and the elongation increases. When the over-aging temperature is 270 ℃, the tensile strength is 1255.0 MPa, the elongation is 11.39%, and the product of strength and elongation is 14.29 GPa·%, and the comprehensive mechanical properties are the best. The reasonable over-aging temperature range of the DP1180 steel should be 230-306.8 ℃.

Key words: continuous annealing process, over-aging temperature, DP1180 steel, microstructure, mechanical properties

CLC Number:

TG156.1

Zhang Jiahao, Chen Liansheng, Gao Tianyang, Xu Haiwei, Han Yun, Li Hongbin, Tian Yaqiang. Effect of over-aging temperature on microstructure and properties of DP1180 steel under continuous annealing process[J]. Heat Treatment of Metals, 2023, 48(1): 149-154.

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