Abstract: The effect of Als、N in 40Mn2 round steel and superheat of molten steel on the steel bar crack is studied by using ARL8820 Direct-reading spectrometer, LECO oxygen-nitrogen-hydrogen gas analyzer, platinum rhodium thermocouple etc. The results show that of heats respectively with 0.021% ~ 0.035% Als, 0. 0065% ~ 0. 0083% N and cast liquid superheat 32 ~ 46 ℃ the Φ50 ~60 mm rolled bar surface occurs crack. After technology improvement, with controlling 0. 015% ~ 0. 025% Als, ≤0. 0060%[ N ] and the superheat of molten steel 18 ~30 ℃，the cracks on the surface of continuous casting billet non-occur and the surface quality of the products is guaranteed.

摘要： 通过使用ARL8820直读光谱仪,LECO氧氮氢气体分析仪和铂铑热电偶等方法,研究了40Mn2圆钢中的Als、N和连铸钢液过热度对钢材裂纹的影响。结果表明:Als、N和连铸钢液的过热度分别为0.021%～0.035%,0.0065%～0.0083%和32～46℃的炉次Φ50～60 mm轧材表面出现了裂纹。工艺改进后,控制钢中的Als 0.015%～0.025%,[N]≤0.0060%,连铸钢液过热度18～30℃,连铸坯表面未出现裂纹,保证了轧材表面质量。

关键词: 40Mn2 钢, Als, N, 过热度, 钢材裂纹