Abstract: The production process flowsheet of tube bloom for 12Mn4V, 37Mn, 26CrMo48V etc steels is 150 t EAF- LF-VD-Φ210~310 mm round bloom casting. Due to the factors including argon shielding no-close etc, during 150 t ladle to 26 t tundish process the increment value of nitrogen content in liquid △N fluctuates largely, the largest △N is up to 65 x 10^-6. With using the measures including improving shroud cleaning implement, increasing mechanical arm counterbalance, improving tight tough touch of ladle flow mouth and shroud, and maintaining argon flow rate 120 L/min and pressure 0.05 MPa, the increment value of nitrogen content in liquid from ladle to tundish is stably less than 5 X 10^-6, and the nitrogen content in casting tube bloom is 30 x 10^-6 ~60 x 10^-6.

摘要： 12Mn4V、37Mn、26CrMo48V等钢种管坯的乍产工艺流程为150 t EAF-LF-VD-Φ210~310 mm圆坯连铸。由于氩封不严密等因素,150 t钢包至26 t中间包过程钢水氮含量增加值△N波动较大,△N最大值达到65×10^-6。通过改进套管清理工具,增加机械手配重,改善钢包流嘴和套管的紧密,保持氩气流量120 L/min,压力0.05MPa等措施,使从钢包到中间包增氮量稳定在5×10^-6以下,连铸管坯氮含量为30×10^-6~60×10^-6。

关键词: 管坯, 26 t中间包, 钢水氮含量, 长水口, 氩气, 保护浇注