Method for adding Mn into high Mn content stainless steel in smelting process

Abstract

The Mn adding method for smelting high Mn content stainless steel features that in the K-OBM-S step, pre-treated molten iron is decarbonized and alloyed in a top and bottom combine blown converter, high carbon ferromanganese in 15-25 wt% of total Mn amount is added in the II decarbonizing stage and low carbon ferromanganese or metal Mn in 75-85 wt% of total Mn amount is added in the last decarbonizing stage and reduction stage, ferrosilicon is added for reducing and trimming components, and the steel is tapped after smelting for 55-65 min, with the steel containing C 0.05-0.25 wt%, Si 0.05-2.00 wt%, Mn 3.00-10.00 wt%, P not more than 0.050 wt%, S not more than 0.030 wt%, Cr 17.00-23.00 wt%, Ni 2.50-12.00 wt%, N not more than 0.250 wt%, Pb 0-0.001 wt%, Cu 0-4.00 wt%, and Fe and inevitable impurity for the rest; and that in the VOD step, Mn in 0-5 wt% of the total Mn amount is replenished. The said Mn adding method results in short smelting period high Mn utilization and low smelting cost.

Description

Technical field [0001] The invention relates to a method for adding manganese in the smelting of stainless steel with high manganese content. Background technique [0002] Adding manganese to stainless steel can improve the performance of stainless steel. For example, adding 3% to 7% manganese to chromium-nickel austenitic stainless steel welding materials (welding wires, electrodes, etc.) can reduce welding cracks and meet the needs of welding; in saving nickel and austenitic stainless steel, In austenitic stainless steel, manganese is a very important alloying element. Its main function is to combine it with nitrogen, nickel and other elements that strongly form austenite into the steel. It can save nickel in austenitic stainless steel, which not only improves quality, performance and price. It can meet the requirements of different users, and can also solve the problem of insufficient nickel resources; add 3% to 10% Mn to high Cr-Ni-Mo austenitic stainless steel to increa...

AI Technical Summary

Problems solved by technology

When the temperature of the molten metal is higher than 1400°C, the affinity of C and O can exceed that of Mn. The existing manganese addition method will increase the amount of Mn oxidation and prolong the de-C smelting time. Not only the recovery rate of Mn is low, with an average of 74%. Moreover, the average smelting time of the K-OBM-S converter is as long as 110 minutes, which prolongs the residence time of the molten metal in the furnace and affects the life of the furnace lining.

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