连续缓慢冷却贝氏体转变特征及合金元素分布的影响

Transformation Characteristic of Slowly Continuous Cooling Bainite and Effect of Alloy Elements in Microstructures

利用热膨胀仪对实验用预硬型塑料模具钢不同冷却速率进行热模拟,观察组织形貌,并用电子探针显微分析仪对不同组织区域进行定点分析,发现Mo,Si在抑制珠光体转变及粒状贝氏体转变过程中起重要作用。在冷速≤0.015℃/s冷却条件下,组织转变较为复杂,转变过程中有珠光体出现。由于内部合金元素微观分布不均匀,贝氏体组织分为片状和成团的粒状两种形貌,珠光体主要在成团粒状区域内出现。

Dilatometric tests were performed on the dilatometer under different cooling rates for the steels and the microstructures were observed.The point analysis of main elements was analyzed with the EMPA.The elements of Mo and Si were important for controlling grain transformation of the pearlite and granular bainite.When cooling rate at≤0.015℃/s,the variation of the microstructures was more complicated.The pearlite could be observed in the cooling slowly,the elements were heterogeneous distribution.The bainites were not the single microstructures,the morphology of bainites were lamellar and disordered granular.The pearlites presented at disordered granular area mainly.