-70℃低温用09MnNiD钢Φ219mm×20mm无缝管生产实践

Production Practice of 09MnNiD Steel Φ219 mm×20 mm Seamless Tube for-70℃Low Temperature and Cryogenic Service

按照20tEAF→LF+VD→模铸3t钢锭→轧制Φ270mm圆钢→斜轧穿孔→CPE轧管→在线常化工艺流程,生产Φ219mm×20mm09MnNiD钢无缝管(/%:0.07-0.10C,0.25-0.35Si,1.35-1.40Mn,0.49-0.51Ni,0.020-0.035Al,≤0.02Nb,≤0.015P,≤0.006S)。通过控制EAF终点C≤0.04%和P≤0.008%,LF精炼S≤0.005%,VD≤67Pa,≥15min,模铸过热度≤45℃,热轧后荒管冷却速度30-70℃/min,钢管常化温度910℃,开发了Φ219mm×20mm钢管。测试结果表明:生产的钢管显微组织为F+P,晶粒度10级,-70℃冲击功KV_(2)≥275J,抗拉强度503-508MPa,屈服强度354-356MPa,以及其化学成分、非金属夹杂物、无损检测均满足GB150.2-2011标准要求。

The Φ219 mm × 20 mm seamless tube of 09 MnNiD steel(/%;0.07~0.10 C,0.25~0.35 Si,1.35~1.40 Mn,0.49~0.51 Ni,0.020~0.035 Al,≤ 0.02 Nb,≤ 0.015 P,≤ 0.006 S) has been produced by 20 t EAF→LF+VD→ ingot casting→ rolling Φ270 mm round billet→ cross piercing→CPE rolling tube→ online normalization.By controlling EAF endpoint [C]≤0.04% and [P]≤0.008%,LF refining [S]≤0.005%,VD≤67 Pa,≥15 min,ingot cast steel overheating ≤45 ℃,cooling rate of hot rolled piercing shell 30~70℃/min,and steel tube normalizing at 910℃.The test results show that the microstructure is F+P,grain size grade 10,-70℃ impact energy KV≥257 J,tensile strength 503~508 MPa,yield strength 354~356 MPa,and the chemical composition,mechanical properties,nondestructive testing meet the requirements of GB 150.2-2011 standard.