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运用拉伸试验、低温冲击试验、光学显微镜和扫描电镜等测试方法,分析不同卷取温度下管线钢中钒含量的变化对管线钢显微组织和力学性能的影响。结果表明:随着卷取温度的升高,显微组织显著变化。在650℃进行卷取,组织以多边形铁素体和珠光体为主,析出物数量少;卷取温度降低至550℃时,显微组织由细小的多边形铁素体和少量的针状铁素体组成,在铁素体晶界处有大量析出物,珠光体数量减少甚至消失;强度随着卷取温度的降低而升高,低温冲击韧性下降。
Tensile test, low temperature impact test, optical microscope and scanning electron microscopy were used to analyze the influence of vanadium content in pipeline steel on the microstructure and mechanical properties of pipeline steel at different coiling temperatures. The results show that with the increase of coiling temperature, the microstructure changes significantly. When the temperature was reduced to 550 ℃, the microstructure was composed of fine polygonal ferrite and a small amount of acicular ferrite There are a lot of precipitates in the grain boundary of ferrite and the number of pearlite decreases or even disappears. The strength increases with the decrease of coiling temperature and the impact toughness at low temperature decreases.