高寒地区用H型钢低温冲击性能分析与改进

莱钢股份炼钢厂开发生产的Q345EL H型钢主要用于高寒地区石油钻井平台建设，要求-50℃低温冲击  性能大于27 J。在生产中出现冲击韧性波动较大、个别炉次偏低的问题，对此进行了分析，认为是严重的带状组织  和钢中的非金属夹杂物含量超标造成的。通过在炼钢工序细化了脱氧制度、采用出钢预熔合成渣渣洗工艺、炼钢过程系统低温控制及“三恒”稳态浇铸等措施，在轧制工序对道次、温度及冷却方式等参数进行调整，该问题得到有效解决。

Analysis and Improvement on Low-Temperature Impact of H Shaped Steel Used of Frigid Regions

Q345EL H shaped steel is mainly used for oil drilling platform in frigid regions,which requires the impact properties at-50 ℃ more than Akv 27 J.The analysis was carried through,aiming at the problem of-40 ℃ impact toughness fluctuation of Q345El H-beam in wider range and some heats on the low side.The conclusion was drawn that serious band structure and excessive non-metallic inclusions in steel caused the above-mentioned problems.The impact toughness fluctuation is effectively resolved by constituting accurate deoxidization rule,adding pre-melting synthetic slag during tapping,low temperature control during BOF steelmaking process and the "three constant" steady-state casting such measures in steelmaking process and by adjusting pass temperature and cooling method such parameters in the rolling process.