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在MMS-300热力模拟机上,利用膨胀法结合金相-硬度法,建立新开发的高速列车焊接构架用Mn-Cu-Ti-Nb低碳钢未变形和变形奥氏体的连续冷却转变曲线,研究了形变和冷却速度对试验钢γ→α相变行为及显微组织的影响。结果表明:随着冷却速率的增加,铁素体转变开始温度降低,铁素体晶粒得到细化,同时还促进了贝氏体相变。变形一方面促进了铁素体相变,细化铁素体晶粒;另一方面又抑制了贝氏体相变,使贝氏体含量降低,硬度降低。
On the MMS-300 thermal simulator, the continuous cooling transformation curve of undeformed and deformed austenite of Mn-Cu-Ti-Nb mild steel for welded structure of newly developed high-speed train is established by means of expansion method combined with metallographic- The effect of deformation and cooling rate on γ → α transformation and microstructure of the test steel was studied. The results show that as the cooling rate increases, the temperature at the start of ferrite transformation decreases and the ferrite grains are refined. Meanwhile, the bainite transformation is also promoted. Deformation on the one hand to promote the ferrite transformation, refinement of ferrite grains; the other hand, inhibit the bainite transformation, the bainite content decreases, reducing the hardness.