Φ25mm细晶粒45钢的研究与生产实践

RESEARCH AND PRODUCTION PRACTICE OF FINE GRAIN 45 STEEL WITH DIAMETER Φ25mm

基于宣钢转炉方坯连铸连轧工艺流程,采用钛铝微合金成分设计,转炉冶炼终点[C]控制在0.15%~0.30%,加入铝锰钛合金1.8~2.5 kg/t进行脱氧。LF精炼过程中,碱度控制在3.0~5.0,精炼周期不小于40 min;连铸全过程采用保护浇铸,过热度控制在20~35℃;轧制过程中,钢坯的上下面、头尾部温差控制在≤50℃。通过上述生产工艺开发的Φ25 mm细晶粒45钢,其铁素体晶粒度达到8级,钢材的强度达到620 MPa以上,具有良好的强度、韧性,能够满足了汽车、机械制造行业的使用要求。

This paper introduces the process for Φ25 mm fine grain 45 steel based on billet continuous casting and rolling process of xuansteel converter,With Ti and Al micro alloy design,BOF smelting endpoint[C]is controlled at 0. 15% ~ 0. 30%,and luminum manganese titanium alloy 1. 8 ~ 2. 5 kg/t is added to deoxidige;the alkalinity is controlled at 3. 0 ~ 5. 0 and refining period is not less than 40 min during LF refining process;the protective casting is adopted in the whole process of continuous casting and superheat is controlled at 20 ~35 ℃; the temperature difference between the upper and the lower of the billet,and between head and tail is less than or equal to 50 ℃. The fine grain 45 steel with Φ 25 mm was developed by the above process,whose ferrite grain size can reach 8 level and the steel strength can reach more than 620 MPa. It can meet the requirements of automobile and machinery manufacturing industry with high strength and good toughness.