论文部分内容阅读
研究了SCM440钢的开裂敏感性与轧后冷却过程中的温度、脱碳程度的关系。结果表明,轧后冷却过程中SCM440大盘条在表层以下30μm以内的区域产生的微裂纹引起了冷镦开裂。在轧后冷却过程SCM440盘卷表面发生脱碳。微裂纹主要在750～800℃范围内产生,由于在这个温度范围内SCM440钢处于两相区,发生了铁素体相变,在表层形成铁素体全脱碳层,最后由于组织应力形成了沿铁素体晶界扩展的微裂纹。
The relationship between the cracking susceptibility of SCM440 steel and the temperature and the degree of decarburization during cooling after rolling was studied. The results show that the microcracks generated in the SCM440 coil during the post-rolling cooling in the area within 30μm below the surface layer caused the cold forging cracking. Decarburization occurs on the coil surface of the SCM440 after cooling during rolling. The microcracks are mainly generated in the range of 750-800 ° C. Since the SCM440 steel is in the two-phase region within this temperature range, ferrite transformation occurs and the ferrite decarburized layer is formed on the surface layer, and finally the stress due to the formation of the structure Micro-cracks spreading along the ferrite grain boundaries.