锰原料对低合金TRIP钢中非金属夹杂物的影响

为了研究不同锰合金原料对TRIP钢洁净度的影响及锰合金中非金属夹杂物的遗传特性,采用SEM-EDS分别检测了电解锰、金属锰和中碳锰铁中非金属夹杂物的类型、形貌和尺寸,并通过高温试验和热力学计算系统探讨了采用3种锰原料进行合金化后TRIP钢中非金属夹杂物特征.结果表明,电解锰中夹杂物主要为MnC、MnC-MnO和MnO-...

Effect of manganese raw materials on non-metallic inclusions in low alloy TRIP steel

To clarify the effects of manganese materials on the cleanness of TRIP steel and the hereditary character from manganese alloys to steels, the type, morphology, and size of non-metallic inclusions (NMI) were detected using SEM-EDS. Then, the NMI characteristics in TRIP steel were systematically discussed based on high-temperature experiments and thermodynamic calculations. The results show that, the main inclusions in electrolytic manganese were MnC, MnC-MnO, MnO-MnS and trace MnO, the main inclusions in manganese metal were single MnO, single MnS and complex MnO-MnS, and the medium carbon ferromanganese mostly contained complex MnO-SiO₂ and MnO-SiO₂-MnS inclusions, the trace MnC particles and enrichment phases of residual elements were also detected. During alloying process, the dominant NMI was Al₂O₃ after the addition of Al and Si, and then the NMIs were changed to Al₂O₃, MnS, AlN, Al₂O₃-MnS and Al₂O₃-AlN after manganese addition after Mn alloying. For TRIP steel, after alloying with electrolytic manganese, manganese metal and medium carbon ferromanganese, there was little difference in the types of NMIs in the steel. Due to the high-Al characteristic in molten steel, the MnC and MnS inclusions from manganese materials were dissolved to molten steel, and then the MnO and SiO₂ inclusions were reduced to Al₂O₃. The evolution route of manganese and silicon oxides during the smelting process was MnO/MnO-SiO₂→Al₂O₃→MnS/Al₂O₃-MnS. During the solidification, pure AlN and MnS inclusions precipitated or Al₂O₃-MnS and Al₂O₃-AlN complex inclusions were formed, due to the enrichment and segregation of Al, N, Mn and S elements. Moreover, the addition of manganese materials may promote the formation of AlN inclusion, the possible explanation was that manganese materials contained N element or Mn increased the solubility of N element.