高强韧性石油装备连接件用钢生产工艺实践

Process Practice of Hight Strength and Impact Steel Used for Adapting Piece of Oil Equipment

淮钢采用90吨顶底复吹转炉+LF炉外精炼+RH真空脱气处理+Φ500mm圆坯连铸的工艺生产4130石油装备连接件用钢(/%:0.30~0.33C,0.20~0.35Si,0.50~0.60Mn,≤0.010P,≤0.003S,1.10~1.20Cr,0.20~0.30Ni,≤0.20Cu,0.20~0.25Mo,0.01~0.02V,0.015~0.040Nb)。通过控制出钢碳≥0.08%,出钢温度1630~1670℃,精炼过程利用电石和铝粒强化渣面脱氧,RH真空度≤100 Pa,真空保持时间≥25min,浇铸过程全程保护浇铸等措施,4130连铸圆坯各项指标均符合技术要求,并且经过用户锻造加工后,取样检测力学性能,屈服强度可以达到95 K级以上,冲击韧性指标也能符合标准要求,非金属夹杂物、晶粒度以及探伤结果均满足用户要求。

The Φ500mm 4130 steel for adapting piece(/%: 0.30~0.33C, 0.20~0.35Si, 0.50~0.60Mn, ≤0.010P, ≤0.003S, 1.10~1.20Cr, 0.20~0.30Ni, ≤0.20Cu,0.20~0.25Mo, 0.01~0.02V, 0.015~0.040Nb) was produced by 90 t LD with top-bottom blowing-LF-RH-Φ500 mm billet concasting-continuous at Huaigang Special Steel. By controlling LD end [C]≥0.08 %, LD end temperature 1630~1670℃, using aluminum particle and carbide to enhance slag surface deoxidation, RH vacuum ≤100 Pa, keeping vacuum time ≥25 min, protecting casting in the whole process, all technical indexes are satisfy customer’s requirements, sampling and test mechanical after forging, the yield strenght is exceed 95K class, impact results also satisfy the specification.Non metallic inclusions, grain size and Ultrasonic test results meet user requirements.