中碳钢连铸方坯内部角裂机理研究与控制
Research Mechanism and Control of Internal Crack of Billet for Continuous Casting of Medium Carbon Steel
袁守谦，姚成功，王治钧，陈列
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作者单位：1西安建筑科技大学 冶金工程学院
2西宁特殊钢股份有限公司技术质量中心
中文关键字：45钢；连铸坯；角裂；工艺
英文关键字：45 steel; billet; internal crack; route
中文摘要：45钢连铸坯在生产中易出现铸坯的内部角裂缺陷。通过低倍试验、金相法和探针能谱分析，发现缺陷处不存在异常和质点沉淀现象；基于ANSYS对结晶器凝固过程进行温度场模拟得出，缺陷萌生于结晶器内，根本原因是铸坯在结晶器中凝固传热不均导致出现铸坯偏角区热节区效应，从而诱导产生热应力作用于凝固前沿致使沿柱状晶晶间铁素体开裂。通过重新设定结晶器铜管圆角半径和优化生产部分工艺后，最终使内部角裂等到明显优化。
英文摘要：The internal crack of Billet of 45 Steel is always occurred in continuous casting process. Macroscopic test, metallographical test, electron probe and energy spectrum analysis are used to research the defects. And finally, there is no abnormal structure and particle precipitation around defects. The solidification process of billet is simulated by ANSYS and getting some conclusions. Defects are formed in the crystallizer. Meanwhile, We can infer that the root cause is the hot spot region formed at the off-corner of billet caused by uneven heat flow in the mould, so the thermal stress emerge subsequently. The region is the weakest position, the cracks formed at intergranular between two adjacent Columnar crystal. Sometimes the bulging of the billet can be found. Re-setting fillet of mold and optimization process of continuous casting the final the internal corner crack is avoided.