形变热处理工艺对低碳微合金管线钢晶粒细化的影响

以管线钢X52为研究对象，在Gleeble1500热模拟机上，进行了奥氏体未再结晶区不同形变速度、形变量和冷却速度对X52的相变行为及显微组织影响的研究。通过光学显微镜、扫描电镜分析可以发现，随变形速率、形变量和冷却速度的增加，晶粒明显变细。同时，低碳钢不同的是在奥氏体未再结晶区扎制时，第二相的析出可以抑制再结晶，并且析出物的存在不仅阻碍位错的运动，而且全造成位错的增殖，因而微合金钢细化昌粒的机理主要有：形变诱导铁素体、铁素体的动态再结晶和第二相的析出抑制晶粒长大使晶粒细化。

Effect of Heat Treatment on the Grain Refinement of Low Carbon Microalloyed Steels for Pipe-line Application

The effect of strain rate, strain amount and cooling rate in non recrystallization region on the ferrite transformation behavior and mocrostructure were studied on a Gleeble 1500 thermo methanical simulator for the low carbon pipeline steel X52. Optical microscopy and SEM observations showecl that the grains became fine with the increase of strain rate, strain amonunt and cooling rate. At the same time, the precipitated second phase can restrain the occurrence of recrystalliztion by deformation in the non recrystallization region, and the existence of second phase not only can hinder the movement of dislocation but also result in didlocation multiplication. Therefore, the mechanisms of grain refinement for micro alloyed steels which are different from the low carbon steels are due to strain induced ferrite, ferrite recrystallization and precipitated second phase which hinders the growth of ferrite and makes grains refined.