鋼包底吹氬精煉混勻判據及合金加入位置研究

  混(hun)勻(yun)時間是衡量(liang)鋼液成(cheng)分均勻(yun)化的(de)重要指標。國內(nei)外學者(zhe)在進行水模(mo)(mo)型(xing)試驗時,通常采(cai)用(yong)“刺激(ji)-響應”技術測(ce)量(liang)監測(ce)點(dian)的(de)局部(bu)混(hun)勻(yun)時間,Kochi等(deng)在水模(mo)(mo)型(xing)試驗中測(ce)定混(hun)勻(yun)時間時,在模(mo)(mo)型(xing)底部(bu)靠(kao)近壁面處安置了1個電導(dao)探頭(tou),取從加入KCl溶液到(dao)電導(dao)率達到(dao)平衡值(zhi)95%~105%時的(de)時間為混(hun)勻(yun)時間,這是最常用(yong)的(de)測(ce)量(liang)混(hun)勻(yun)時間的(de)方法。但是電導(dao)探頭(tou)測(ce)量(liang)的(de)混(hun)勻(yun)時間僅代表該點(dian)周圍局部(bu)區(qu)域的(de)混(hun)勻(yun)時間。

  科研工作者針對由于鋼包各處混(hun)勻時間差異較大,加(jia)之(zhi)監(jian)測點位置選擇(ze)的主觀性,易造(zao)成混(hun)勻時間測量(liang)不(bu)準的問題(ti),通過數值計(ji)算的研究(jiu)方法模擬了鋼液的流動與(yu)混(hun)勻過程。

  計算結果表明(ming):隨(sui)著鋼液(ye)混(hun)(hun)(hun)勻(yun)(yun)程度(du)的增(zeng)加(jia)(jia),鋼液(ye)中(zhong)(zhong)(zhong)整(zheng)體示(shi)(shi)(shi)蹤(zong)(zong)(zong)(zong)(zong)(zong)劑(ji)濃度(du)標(biao)(biao)準(zhun)(zhun)差降(jiang)低,當(dang)整(zheng)體示(shi)(shi)(shi)蹤(zong)(zong)(zong)(zong)(zong)(zong)劑(ji)濃度(du)標(biao)(biao)準(zhun)(zhun)差在(zai)約0.02以(yi)下(xia)時(shi)(shi)(shi),鋼包(bao)混(hun)(hun)(hun)勻(yun)(yun)程度(du)已達(da)到100%,基于此提出在(zai)水模型試驗中(zhong)(zhong)(zhong)測量混(hun)(hun)(hun)勻(yun)(yun)時(shi)(shi)(shi)間(jian)時(shi)(shi)(shi),可(ke)以(yi)在(zai)鋼包(bao)中(zhong)(zhong)(zhong)3個不(bu)(bu)同(tong)高度(du)處(chu)各安裝3個電(dian)導(dao)探頭監測示(shi)(shi)(shi)蹤(zong)(zong)(zong)(zong)(zong)(zong)劑(ji)濃度(du)變(bian)化,當(dang)這(zhe)9處(chu)監測點示(shi)(shi)(shi)蹤(zong)(zong)(zong)(zong)(zong)(zong)劑(ji)濃度(du)標(biao)(biao)準(zhun)(zhun)差小于0.02時(shi)(shi)(shi),即可(ke)認為(wei)達(da)到混(hun)(hun)(hun)勻(yun)(yun)。研究了不(bu)(bu)同(tong)示(shi)(shi)(shi)蹤(zong)(zong)(zong)(zong)(zong)(zong)劑(ji)加(jia)(jia)入(ru)位(wei)置(zhi)下(xia)的混(hun)(hun)(hun)勻(yun)(yun)時(shi)(shi)(shi)間(jian),結果表明(ming),在(zai)鋼包(bao)一側距離鋼包(bao)中(zhong)(zhong)(zhong)心約1/6R處(chu)加(jia)(jia)入(ru)示(shi)(shi)(shi)蹤(zong)(zong)(zong)(zong)(zong)(zong)劑(ji)時(shi)(shi)(shi),混(hun)(hun)(hun)勻(yun)(yun)時(shi)(shi)(shi)間(jian)最(zui)短為(wei)77.5s,該位(wei)置(zhi)為(wei)理想的合(he)(he)金(jin)加(jia)(jia)入(ru)位(wei)置(zhi)。而在(zai)靠近氣液(ye)兩(liang)相區的鋼包(bao)液(ye)面邊緣處(chu)加(jia)(jia)入(ru)示(shi)(shi)(shi)蹤(zong)(zong)(zong)(zong)(zong)(zong)劑(ji)時(shi)(shi)(shi),混(hun)(hun)(hun)勻(yun)(yun)時(shi)(shi)(shi)間(jian)最(zui)長為(wei)137.3s,在(zai)該位(wei)置(zhi)加(jia)(jia)入(ru)合(he)(he)金(jin)則不(bu)(bu)利于鋼液(ye)的快速(su)混(hun)(hun)(hun)勻(yun)(yun)。