不同终冷温度下管线钢热轧板的组织与织构演变

Microstructure and texture evolution of hot rolled pipeline steel at different final cooling temperature

研究了X80管线钢在不同终冷温度下的微观组织与主要热轧织构组分的演变规律。借助光学显微镜(OM)及扫描电子显微镜(SEM)观察了热轧板的显微组织形态,利用X射线衍射技术(XRD)测定了热轧板从表面到心部不同距离的宏观织构组成,探讨了平行于板厚方向的织构变化趋势。结果表明,轧后终冷温度较高时,易于形成多边形铁素体,同时存在极少量珠光体;随着终冷温度降低,多边形铁素体数量减少,粒状贝氏体明显增多;终冷温度为550℃时,显微组织为准多边形铁素体+粒状贝氏体+M/A岛,为典型的针状铁素体复相组织。随着终冷温度的降低,沿板厚方向α取向线上的密度总体呈降低的趋势,尤以{001}<110>与{112}<110>织构组分降低幅度明显,而{110}<110>取向密度的变化趋势则有所升高。

The microstructure and macro texture components evolution of X80 hot-rolled pipeline steel at different final cooling temperatures were studied.The microstructure of hot rolled plate under different surface-to-core distance of X80 pipeline steel was observed by optical microscopy ( OM) and scan electron microscopy ( SEM) .Meanwhile, the macro texture was measured by utilizing X-ray diffraction ( XRD) method, and the texture change parallel to the thickness direction was investigated.The results indicate that polygonal ferrite is easy to form at the higher final cooling temperatures and there is very little pearlite.With decreasing of the final cooling temperature, the number of polygonal ferrite reduces, and the granular bainite increase significantly.When the final cooling temperature is at 550℃, the microstructure consist of quasi-polygonal ferrite, granular bainite and M/A Island, which is the typical acicular ferrite multi-phase microstructure.With decreasing of the final cooling temperature, the density at theαorientation line along the thickness direction overall decreases, especially for the{001} <110>,{112} <110>texture components, while the{110} <110>orientation density is somewhat increasing gradually.