汽车大梁钢控氮工艺的优化

The optimization of nitrogen control technology for automobile beam steel

氮元素是钢中典型的有害元素,在结晶过程中,钢中氮的溶解度急剧降低,析出氮化铁(FeN、Fe 4N)位于晶界上阻止位错移动,虽可提高钢的强度和硬度,但会严重降低钢材塑性,易在后期加工过程出现开裂现象,同时氮含量易与钢中钛发生反应,降低有效钛,降低钢材性能。本文介绍了工业生产全流程氮含量变化,分析了钢中氮含量升高的主要因素并制定整改措施。通过明确转炉铁水、石灰、合金等原辅料的入炉标准,优化转炉吹炼枪位和炉后脱氧工艺,同时提高精炼埋弧效果,稳定控制大梁钢成品氮含量≤45 ppm,合格率达到95%。

Nitrogen element is a harmful element in steel,its content is too high will deterioration of hot rolling and cold rolling performance of steel,reduce the plastic toughness of steel,and even reduce the timeliness of steel or cause blue brittleness,serious may lead to processing cracking.And nitrogen content is easy to react with titanium in steel,reduce the effective titanium,affecting the performance of steel.This paper introduced the change of nitrogen content in the whole process of industrial production,analyzed the main factors of nitrogen content increase in steel,and made rectification measures.By clarifying the standard of raw materials in the converter such as molten iron,lime and alloy,optimizing the converter blow gun position and post-furnace deoxidation process,and improving the submerged arc effect of refining,we could stably control the finished nitrogen content of beam steel≤45ppm and the pass rate reaching 95%.