热轧工艺对X65管线钢的组织与性能的影响

Effect of hot rolled process on microstructure and properties of X65 pipeline steel

采用光学显微镜、扫描电镜和拉伸试验等方法研究了X65管线钢的显微组织、力学性能及冲击韧性,对粗轧后的高温奥氏体晶粒进行了分析。结果表明,X65管线钢板组织比较细小、均匀,铁素体晶粒呈不规则的多边形或针状,约为6μm;经5道次粗轧后的高温奥氏体晶粒呈多边形,晶粒度平均为8.5级;成品板的铁素体晶粒内部或晶界处有析出相粒子;由于晶粒组织细小且钢中有害元素、夹杂物的含量低,故板的强度和韧性高。

The mlcrostructure, mechanical properties and impact toughness of X65 pipeline steel were studied by means of optical microscope, SEM and tensile test. The grains of austenite at high temperature after rough roiling were analysed. The results show that the microstructure of X65 pipeline steel strip is fine and homogeneous, the grains of ferrite which is about 6 Ixm are irregular polygon or acicular; the grains of austenite at high temperature after five-pass rough rolling are polygon, and average grain degree is 8.5 ;there are precipitate phase particles in the inner ferrite grain or grain boundary of finished strip. The strength and toughness of X65 pipeline steel strip are high because of the fine microstructure and low content of deleterious components and impurities.