Influence of Coiling Temperature on Microstructure, Precipitation Behaviors and Mechanical Properties of a Low Carbon Ti Micro-Alloyed Steel

Metals

Wenbo Du¹  Mingxue Sun²  Yang Xu² 

[1] National Key Laboratory for Remanufacturing, Academy of Army Armored Forces, Beijing 100072, China;School of Mechanical and Automotive Engineering, Qingdao University of Technology, Qingdao 266520, China;

关键词: coiling temperature;    microhardness;    nanosized precipitation;    precipitation strengthening;   

DOI  :  10.3390/met10091173

来源: DOAJ

【 摘 要 】

The microstructural evolution, nanosized precipitation behaviors and mechanical properties of a Ti-bearing micro-alloyed steel at different coiling temperatures were studied using optical microstructure (OM), scanning electron micrograph (SEM), transmission electron microscopy (TEM), Vickers hardness and tensile tests. When the coiling temperature was 500 °C, the specimen showed mainly bainitic structure, whereas polygonal ferrite was visible as the coiling temperature increased to 650 °C and 700 °C. The Vickers hardness of tested steel reached the maximum, which can be attributed to the largest number of nanosized precipitates in ferrite at the coiling temperature of 650 °C. A coiling temperature of 650 °C was optimal for the formation of TiC because of the high diffusion rate of alloying elements and kinetics of precipitation. In the laboratory rolling experiment, when the coiling temperature was 630 °C, the steel with yield strength of 682 ± 2.1 MPa and tensile strength of 742 ± 4.9 MPa was produced. The fine-grain strengthening and precipitation strengthening were 262 MPa and 268 MPa, respectively.

【 授权许可】

Unknown