热轧高锰钢晶间氧化的研究

Study on Intergranular Oxidation of Hot-Rolled High-Manganese Steel

热轧高锰钢板边部出现带状裂纹,大多数裂纹深度较浅,约为300~500μm。试验发现,高锰钢连铸坯边部有大量发达的柱状晶,表层几乎没有细小的等轴晶。高碳高锰钢属于易发生选择性氧化的钢种,加热过程中裸露的柱状晶晶界是氧原子扩散的通道,发达的柱状晶更易氧化,这是热轧高锰钢板产生裂纹的主要原因。因此,采取了降温轧制、缩短高温保温时间、控制残氧量等措施来减轻高锰钢板晶间氧化的程度。钢中增加铬含量也有效抑制了高碳高锰钢板在热轧加热过程中的晶间氧化。

The hot-rolled high-manganese steel plate presented zonal cracks in its edge. Most of the cracks are relatively shallow, being as deep as about 300 to 500 μm. It was found from the investigation that there were a lot of developed columnar crystals in tile eontinuously cast high-manganese steel billet, whereas few fine equiaxed crystals existed in it. The high-carbon high- manganese steel is easy to create selective oxidation, and the columnar erystal boundary exposed to air is a passage through which oxygen atoms diffuse in the steel, and the developed columnar crystals are more easy to be oxidized, which is main reason why the hot-rolled high-manganese steel plate cracked. In view of lhe above, intergranular oxidation seriousness of the hot-rolled high-manganese steel plate was reduced by rolling at reduced temperature, shortening time at high temperature, control of residual oxygen amount and so on. The intergranular oxidation of the hot-rolled high-manganese steel plate during healing for hot rolling also was effectively restrained by the increase in chromium content in it.