Effects of Coiling Temperature on Strength, Yield Ratio and Precipitation Behaviors of Hot Rolled High Strength Microalloyed Steel for Cold Forming
Various hot rolling schedules were applied to a Nb, V, Ti contained HSLA steel. Coiling temperature had crucial effects on not only yield strength, but also yield ratio and precipitation behavior. 600Mpa yield strength is achieved when coiled at 450℃, which is 100Mpa higher than those coiled at 570℃. However, the low coiling temperature had adverse effect to increase yield ratio, which increased from 0.78 to 0.88 as coiling temperature dropped from 570℃ to 450℃. High resolution SEM analysis shows that sizes of Nb, V, Ti precipitates are affected by coiling temperature. Coarse (Nb, Ti)(C, N) precipitates up to 5μm are observed at higher coiling temperature and to decrease tensile strength, where high coiling temperature corresponds to low cooling rate. With strong cooling and coiling capacity of Shasteel’s 1450mm width hot rolling mill, these results indicate that strength and formability of the steel can be balanced when coiling temperature has been optimized. Alloying and microalloying costs can be reduced by efficiently utilizing the capacity of rolling mill. Alumina inclusions are found to act as nucleus for Nb, V, Ti precipitates, contributing to coarsening of precipitates.
coiling temperature strength yield ratio precipitates inclusions
XU Jian-qiu JIA Yue-cai LI Hua-long
Institute of Research of Iron and Steel (IRIS), Sha Steel, Zhangjiagang city, Jiangsu province, 215625, P. R. China
国际会议
The 6th International Conference on High Strength Low Alloy Steels(第六届高强度低合金钢国际会议HSLA Steels2011)
北京
英文
651-654
2011-05-31（万方平台首次上网日期，不代表论文的发表时间）