摘要
非调质钢C70S6 BYΦ60 mm棒材的生产流程为60 t UHP EAF-LF-VD-240 mm×240 mm坯连铸-连轧。连轧材经现场超声波探伤并对缺陷定位取样,通过低倍、金相显微等检验方法对缺陷进行分析,得出该缺陷为心部裂纹,其产生原因主要是铸坯加热不均和轧后冷却应力较大造成。通过改善铸坯加热工艺,将加热二段温度从1 239℃提高至1 248℃,总加热时间≥2.0 h,均热段1 232℃20～40 min,轧后冷却由堆冷24 h改成坑冷38 h,探伤不合格率由36. 80%降至0. 78%。
The production flow sheet of Φ60 mm bar products of non-quenching and non-tempering steel C70 S6 BY is60 t UHP EAF-LF-VD-240 mm ×240 mm bloom casting-continuous rolling. The parts of defects of continuous-rolled products are sampled by ultrasonic detection, defined defect position and sampling, and analyzed by macrostructure and microstructure examination. It is obtained that the defects are center cracks;its forming cause is casting bloom non-uniform heating and producing larger cooling stress after rolling. With using the measures including improving casting bloom heating process, increasing heating temperature at second zone from 1 239 ℃ to 1 248℃, total heating time ≥2.0 h, temperature of bloom at soaking zone being 1 232 ℃ for 20 ~40 min, modified the cooling process after rolling from stacking cooling for 24 h to pit cooling for 38 h, the off-qualified rate of products by ultrasonic detection decreases from original 36.80% to 0. 78%.
作者
康湉
刘向艳
杨建华
翟军
孙琦
穆立峰
马群
Kang Tian;Liu Xiangyan;Yang Jianhua;Zhai Jun;Sun Qi;Mu Lifeng;Ma Qun(Continuous Rolling Mill,Fushun Special Steel Co Ltd,fushun 113001;Blooming Mill,Fushun Special Steel Co Ltd,fushun 113001;Technology Center,Fushun Special Steel Co Ltd,fushun 113001)
出处
《特殊钢》
北大核心
2019年第2期21-23,共3页
Special Steel
关键词
胀断连杆用非调质钢C70S6
BY
探伤
心部裂纹
工艺改进
Non-Quenching and Non-Tempering Steel C70S6 BY for Fracture Splitting Connecting Rod
Ultrasonic Detection
Center Cracks
Process Improvement
