Teshugang (Jul 2024)
Transformation of the Completely Enclosed Atmosphere in Ordinary Electroslag Furnace and Its Influence on Typical Steel Grades
Abstract
As the quality of electroslag steel continues to be improved， the ordinary electroslag furnace requires urgent upgrading to a fully airtight atmosphere protection system， aiming to address issues such as element burning loss， oxygen and hydrogen increase， and hydrogen porosity during the electroslag remelting （ESR） process. A novel atmosphere modification technology for electroslag furnaces has been used to conduct the comparative experiments between the traditional atmosphere protection electroslag furnace and the novel electroslag furnace on GCr15SiMn bearing steel and GH2132 superalloy， using electroslag furnaces with capacities of 5 t and 2 t， respectively.In the novel electroslag furnace， it has achieved an oxygen partial pressure as low as 1×10-6 in the mold during the melting process. The experimental results show that under traditional atmosphere protection in electroslag furnaces， the titanium yield in GH2132 is low， only 88%； The oxygen increase in GCr15SiMn bearing steel during the ESR process ，w［O］ can reach up to 5×10-6.In the novel atmosphere protection modification， the titanium yield in GH2132 reaches as high as 96%； The oxygen w［O］ increase in bearing steel during the ESR process is controlled within 3×10-6， and the oxygen w［O］ content in the electroslag ingot is stably controlled within 10×10-6. The quality of the electroslag ingots matches that of atmosphere-protected electroslag furnaces.In the remelting process， bearing steel w［O］ is controlled within 3×10-6， w［O］ in electric slag ingot is controlled within 10×10-6， and the effect of electric slag ingot is comparable to that of gas protection slag furnace. Above detection results of oxygen partial pressure in furnace and electric slag ingot show that after electric slag furnace atmosphere modification， it can effectively solve the problems like slag oxygen potential increase and the electric slag ingot caused by the oxide skin falling into the slag， which are the traditional atmosphere protection transformation technology， the recurrent heat wave emission and negative pressure suction caused by the unstable argon protection in the mold， resulting in the electrode surface oxidation， Especially for GH2132 high Ti low Al type superalloy， under the condition of adding deoxidant Al in ordinary electric slag furnace， it can only cause Al increase in electric slag ingot.
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