Maolin Hou, Aiqing Ding

(College o Engineering, Liaoning University of Technology)

Abstract：

This article discusses and analyzes the law of nitrogen increase in liquid steel and the main factors affecting the nitrogen increasing of molten steel，through the way of adding nitrogen to molten steel by bottom blowing nitrogen gas in LF refining process. It is considered that the main factors affecting the nitrogen increasing instability of molten steel are the initial temperature of LF refining，nitrogen relative element， surface active elements［O］and［S］of steel liquid，and bottom blowing rate of ladle. The large － scale production practice shows that T［O］ not more than 50 × 10^－6 and［S］is not more than 0.020 in LF refining at the initial temperature of not less than 1570 ℃. The liquid steel nitrogen enrichment test is carried out by ladle bottom blowing nitrogen gas after 20 min of refining，the flow rate is set as(6.0 ～7.0) NL/min per ton，and it is turned to 2 NL/min at 6 min before the end of refining，the nitrogen increasing rate of liquid steel is basically stable at (5 ～ 6) × 10^－6 per minute．

Key Words：

LF refine; bottom blowing nitrogen gas; nitrogen increase in liquid steel; process practice