齿轮钢20CrMnTiH淬透性/宏观偏析控制

针对近期ø500 mm断面20CrMnTiH淬透性波动幅度较大问题,通过改变拉速、结晶器电磁搅拌、二冷比水量等参数,对比取样分析改变参数前后的低倍组织、碳偏析量以及淬透性。结果表明,采用改变后的生产参数进行生产,等轴晶率下降幅度较小,宏观偏析以及淬透性波动幅度明显下降,产品质量提升明显。生产参数调整对比中150 A、1.5 Hz结晶器电磁搅拌参数下的宏观偏析和淬透性波动情况明显好于200 A、1.5 Hz结晶器电磁搅拌参数情况。因此,采用拉速0.35 m/min、二冷区各分段水量为40 L/min、21 L/min、13 L/min,二冷比水量0.134 L/kg、结晶器电磁搅拌150 A、1.5 Hz以及末端电搅100 A、7 Hz参数,改善了齿轮钢20CrMnTiH淬透性/宏观偏析波动大的情况。

Gear steel 20CrMnTiH hardenability/macro segregation control

Aiming at the large fluctuation of 20CrMnTiH hardenability of ø500 mm section recently, by changing the parameters such as pulling speed, mold electromagnetic stirring, and secondary cooling specific water, the low magnification structure, carbon segregation amount and hardenability before and after changing parameters were compared and analyzed. The results show that when the changed production parameters are used for production, the equiaxed crystal rate decreases slightly, the macro-segregation and hardenability fluctuations decrease significantly, and the product quality improves significantly. In the adjustment and comparison of production parameters, the macro-segregation and hardenability fluctuations under the electromagnetic stirring parameters of the 150 A and 1.5 Hz molds are significantly better than those under the electromagnetic stirring parameters of the 200 A and 1.5 Hz molds. Therefore, the pulling speed is 0.35 m/min, and the water volume of each section in the secondary cooling zone is 40 L/min, 21 L/min, and 13 L/min, 0.134 L/kg specific water volume of the secondary cooling zone, 150 A、1.5 Hz electromagnetic stirring in the crystallizer and 100 A、7 Hz electric stirring at the end, the high hardenability / macro segregation fluctuation of 20CrMnTiH gear steel is improved.