普通电渣炉的全密闭气氛改造及其对典型钢种的影响

Transformation of the Completely Enclosed Atmosphere in Ordinary Electroslag Furnace and Its Influence on Typical Steel Grades

随着电渣钢品质的不断提升,普通电渣炉亟须进行全密闭气氛保护的升级改造,从而解决电渣重熔过程元素烧损、增氧、增氢、氢气孔等问题。采用新型的电渣炉气氛改造技术,分别用5 t和2 t电渣炉对GCr15SiMn轴承钢和GH2132高温合金进行传统气氛保护电渣炉和新型电渣炉的对比试验。冶炼过程中实现了结晶器内氧分压低至1×10^(-6)。试验数据显示,传统气氛保护电渣炉冶炼下,GH2132中Ti收得率低,仅为88%;GCr15SiMn轴承钢电渣重熔过程中增w[O]量大,可达5×10^(-6)。而在新型气氛保护改造中,GH2132中的Ti收得率高达96%;重熔过程轴承钢增w[O]控制在3×10^(-6)以内,电渣锭中w[O]稳定控制在10×10^(-6)以内,其电渣锭效果媲美气保电渣炉。以上炉内氧分压和电渣锭检测结果表明,电渣炉气氛改造后,可有效解决传统气氛保护改造技术下,往复的热浪涌出和负压吸气导致的结晶器内氩气保护不稳定,从而造成电极表面氧化,氧化皮掉入渣中引起的熔渣氧势升高和电渣锭增氧的问题;尤其对于GH2132高Ti低Al型高温合金,普通电渣炉加入脱氧剂Al条件下,无法避免Ti的烧损,只能导致电渣锭增Al。

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.