A low-cost process of increasing nitrogen and controlling nitrogen in rh molten steel

Abstract

A low-cost RH molten steel nitrogen increasing process belongs to the technical field of steelmaking. The process route of "converter-ladle furnace refining-RH refining-continuous casting" is used for smelting; converter tapping adopts deoxidation alloying, and vanadium-iron alloy is added to match vanadium according to the target value of the steel type during the tapping process, and the molten steel temperature is raised according to the normal process in the ladle furnace , alloy fine-tuning and deep desulfurization treatment, after the molten steel is hoisted to the RH furnace, the lifting gas of the RH furnace is set to nitrogen, the flow rate is controlled according to 800-1200NL / min, and the vacuum treatment time is 8-10min. Blowing operation, to reach the level of nitrogen content in steel at 80-120ppm. The advantage is that it can partially replace the vanadium-nitrogen alloy and reduce the cost of the alloy; ensure the stability of the nitrogen content and reduce the performance fluctuation of the steel plate caused by the composition fluctuation; the RH refining stage uses nitrogen instead of argon to realize the dual functions of process and composition control, further reducing the steelmaking process cost.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and in particular provides a low-cost RH molten steel nitrogen-increasing and nitrogen-controlling process, which is suitable for the production of high-strength low-alloy steels strengthened by precipitation of vanadium and nitrogen, and can stably control steel with a relatively low-cost process. Medium nitrogen content, so as to meet the performance requirements of the steel plate. Background technique [0002] Alloy costs account for a relatively large proportion of the entire steel plate cost. Substituting low-value alloys for high-value alloys is an effective way to reduce product costs under the premise of ensuring performance requirements. Vanadium-nitrogen alloy is a new type of alloy additive that can replace ferro-vanadium. for the production of microalloyed steels. The addition of vanadium nitride to steel can improve the comprehensive mechanical properties of steel such as stren...

AI Technical Summary

Problems solved by technology

However, under conventional smelting process conditions, the composition adjustment is mainly carried out by vanadium nitrogen alloy. This method has many disadvantages: such as inappropriate ratio of vanadium nitrogen, unstable or low absorption rate of nitrogen element, etc., which has caused serious damage to the production of vanadium nitrogen steel. greater impact