摘要
82B高强度钢(/%:0.79~0.83C,0.15~0.25Si,0.72~0.80Mn,≤0.020P,≤0.015S,≤0.15Cu,0.18~0.30Cr)的工艺流程为BOF-LF-165 mm×165 mm坯连铸-热轧至中12.5 mm盘条-冷拔Φ5.05 mm材。线材冷拔断口的分析得出,因偏析产生明显的中心马氏体和网状渗碳体,大颗粒MgO-CaO-Al_2O_3-SiO_2复合夹杂,表面缺陷等因素导致冷拔断裂。通过钢水过热度由原25~35℃降至15~25℃,铸坯拉速由1.80 m/min降至1.65m/min,二次冷却水量由0.80 L/kg降至0.65 L/kg,软吹时间由10 min增至12 min,保证轧后250℃3 h时效等工艺措施,使铸坯中心疏松、中心偏析和缩孔级别分析从1.5,1.0和0.5~2.5降至0.5,0.5和0~0.5,夹杂物总量由0.003 5%~0.004 3%降至0.001 7%~0.002 1%,基本杜绝线材冷拔脆断出现。
The process flowsheet for high strength steel 82B （/% ： 0. 79 - 0. 83C, 0. 15 -0. 25Si, 0. 72 -0. 80Mn, 〈0. 020P, 〈0. 015S, 〈0. 15Cu, O. 18 N0. 30Cr） is BOF-LF-165 mm x 165 mm billet casting-hot rolling to qbl2. 5 mm coil-cold drawing to qb5.05 mm products. It is obtained by analysis on cold-drawn fracture of wire rod that the factors inclu- ding obvious martensite at center of wire rod and network of cementite produced by segregation, large size MgO-CaO-A12 03- SiO2 compound inclusions and surface defects lead to cold drawn fracture of wire rod. With the process measures including decreasing the overheating extent of liquid from original 25 N 35 ℃ to 15 N 25 ℃, decreasing the billet casting speed from 1.80 m/min to 1.65 m/min, decreasing the amount of secondary cooling water from 0. 80 L/kg to 0.65 L/kg, increasing the soft argon blowing time from 10 min to 12 min and insuring aging for 3 h at 250 ℃ after rolling, the rating of center po- rosity, center segregation and shrinkage cavity of casting billet decreases respectively from 1.5, 1.0 and 0. 5 - 2. 5 to 0. 5, 0. 5 and 0 - 0. 5, and the total content of inclusions in steel decreases from 0.003 5% - 0.004 3% to 0.001 7% 0. 002 1% to basically avoid the occurrence of cold drawn fracture of wire rod.
作者
李玮
白宗奇
Li Wei Bai Zongqi(Technology Center, Chengde Iron and Steel Co, Hesteel Group, Chengde 06700)
出处
《特殊钢》
北大核心
2017年第4期16-19,共4页
Special Steel
关键词
82B高强度钢
线材
冷拔断裂
马氏体
偏析
工艺改进
Material Index
High Strength Steel 82B, Wire Rod, Cold Drawing Fracture, Martensite, Segregation, Process Im-provement
