Q420B铁塔角钢裂纹的成因分析和工艺优化  

Analysis on Forming Cause for Crack of Anger Steel Q420B for Tower and Process Optimization

作　　者：姚娜[1] 兴超 

机构地区：[1]济源职业技术学院

出　　处：《特殊钢》2016年第6期32-34,共3页Special Steel

摘　　要：Q420B铁塔角钢（/%：0.12～0.17C,0.15～0.35Si,1.25～1.60Mn,≤0.035P,≤0.035S,0.06～0.09V）的生产流程为60 t转炉-LF-220 mm×290 mnm坯连铸-型钢轧制。铁塔角钢成品酸洗后发现部分批次出现裂纹和表面夹杂,分析表明,裂纹深度达1 mm,有夹杂物和氧化、脱碳现象。通过保护渣碱度从0.97降至0.79,粘度由0.236 Pa·s提高至0.450 Pa·s,连铸坯矫直温度从900℃提高至1 000℃,二冷比水量从0.9 L/kg降至0.7L/kg等工艺措施,铸坯的合格率由93%提高到97%,并有效地避免了角钢裂纹的形成。The production flowsheet for angle steel Q420B for tower （/% ： 0. 12 - 0. 17C, 0. 15 - 0. 35Si, 1.25- 1.60Mn, ≤0. 035P, ≤0. 035S, 0. 06 -0. 09V） is 60 t BOF-LF-220 mm ×290 mm bloom casting-section steel rolling. The surface cracks and inclusions occur at partial batches of finished tower anger steel products after pickling and the analy- sis results show that the depth of cracks is up to 1 mm with inclusions, oxidation and decarburization phenomenon. With the process measures including decreasing the basicity of mould shielding powder from 0. 97 to 0. 79 and increasing its vis- cosity from 0. 236 Pa · s to O. 450 Pa · s, increasing the straightening temperature casting slag from 900 ℃ to 1 000 ℃ and decreasing the secondary cooling water rate from 0. 9 L/kg to 0. 7 L/kg, the qualified rate of casting bloom increases from 93% to 97% and it is available to avoid the formation of crack of angle steel.

关 键 词：Q420B铁塔角钢 表面裂纹 成因分析 保护渣粘度 二冷比水量 

分 类 号：TF777[冶金工程—钢铁冶金]