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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 of X80 pipeline steel at different final cooling temperatures and the evolution of the main hot rolling texture components were studied. The microstructure of the hot-rolled sheet was observed by optical microscope (OM) and scanning electron microscope (SEM). The macroscopic textures of the hot-rolled sheet at different distances from the surface to the heart were measured by X-ray diffraction (XRD) The change trend of texture parallel to the thickness direction was discussed. The results show that polygonal ferrite and very few pearlite are easy to form when the post-rolling final cooling temperature is high. As the final cooling temperature decreases, the number of polygonal ferrite decreases and granular bainite increases obviously. The final cooling temperature At 550 ℃, the microstructure is quasi-polygonal ferrite + granular bainite + M / A island, which is a typical acicular ferrite complex phase. With the decrease of the final cooling temperature, the density along the thickness direction α tends to decrease, especially the {001} <110> and {112} <110> texture components decrease obviously, while {110 } <110> The trend of orientation density has been increased.