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通过Gleeble热模拟试验机模拟在不同初始冷却温度的快速冷却,通过拉伸性能和组织、微观结构分析等手段,研究了L830管线钢冷却开始温度与力学性能之间的关系。研究结果表明:管线钢的抗拉强度随初始冷却温度的升高而升高,塑性随初始冷却温度升高先增加而后降低。在临界温度进行快速冷却获得的管线钢都具有贝氏体和铁素体双相组织。初始冷却温度由810℃升至900℃,铁素体体积分数逐渐降低而贝氏体体积分数升高。选取870℃为临界温度,管线钢显微组织中微小的贝氏体的含量为63.2%,剩余铁素体中含有大量位错,使其具有较高的强度和良好的塑性。
The Gleeble thermal simulator was used to simulate the rapid cooling at different initial cooling temperatures. The relationship between the cooling onset temperature and mechanical properties of L830 pipeline steel was studied by means of tensile properties, microstructure and microstructure analysis. The results show that the tensile strength of pipeline steel increases with the initial cooling temperature, plasticity increases first and then decreases with the increase of initial cooling temperature. Pipeline steels obtained by rapid cooling at the critical temperature have bainitic and ferritic duplex structure. The initial cooling temperature increased from 810 ℃ to 900 ℃, the volume fraction of ferrite gradually decreased and the volume fraction of bainite increased. Select the critical temperature of 870 ℃, microstructure of the pipeline microstructure of small bainite 63.2%, the remaining ferrite contains a large number of dislocations, making it with high strength and good ductility.