洁净钢的脱氧分析课件

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,洁净钢的脱氧分析,洁净钢的脱氧分析,一，碳氧平衡,间接氧化：,2O,2C,2CO,2O,C,CO2,C,的氧化产物绝大,多数是,CO,而不是,CO2,。,C,含量高时，,CO2,也是脱碳反应的氧化剂。,一，碳氧平衡间接氧化：2O 2C 2CO 2,C,?,O,乘积：,C+O=CO,?,G,?,20482,38.94T,1,2,036,.,2,1070,log,log,?,?,?,?,T,O,C,P,K,CO,取,P,CO,1 atm,036,.,2,1070,10,?,?,?,?,T,O,C,1Reed Thomas,Free Energy of Formation of Binary Compounds,MIT Press,1971,2J.F.Elliott,Thermochemistry for Steelmaking,Vol.2,Addison-Wesley,1963,C?O乘积：C+O=CO?G?204,温度,C,?,O,1500K,0.001781,1600K,0.001974,1700K,0.002161,1800K,0.002342,1900K,0.002517,2000K,0.002685,0,0.1,0.2,0.3,0.4,0.5,0.6,0,0.2,0.4,0.6,0.8,1,C，wt%,O,，,w,t,%,1650,温度 C?O 1500K 0.001781 1600,C+O=CO,?,G,?,20482,38.94T,1,2,036,.,2,1070,log,log,?,?,?,?,T,O,C,P,K,CO,036,.,2,1070,10,?,?,?,?,?,T,CO,P,O,C,1Reed Thomas,Free Energy of Formation of Binary Compounds,MIT Press,1971,2J.F.Elliott,Thermochemistry for Steelmaking,Vol.2,Addison-Wesley,1963,真空碳脱氧,C+O=CO?G?2048238.94T,洁净钢的脱氧分析课件,RH,真空脱碳时，,C,、,O,反应生成,CO,气体，降低真空中,CO,分压，使,C,和,O,的反应生成,CO,气体的方向进行,:,C+O=CO(g),其反应的平衡常数为,:,K=p,co,/(a,C,a,O,),=p,co,/(f,C,%Cf,O,%O),当钢液中碳和氧的浓度很小时,f,C,和,f,O,可以看做,1,，则,:,K=p,co,/(%C%O),脱碳反应的热力学,RH真空脱碳时，C、O反应生成CO气体，降低真空中C,由上式可以看出，当降低钢液上气相压力,p,co,时，,C,与,O,的积也相应减少。不同压,力条件下的碳氧平衡曲线如图所示。随着,系统压力的降低，形成一氧化碳的反应物,C,和,O,的含量也相应减少，从面达到脱,碳目的。,由上式可以看出，当降低钢液上气相压力pco时，C与O,温度为,1600,时不同分压,pCO,条件下的碳氧平衡等压曲线,温度为1600时不同分压pCO条件下的碳氧平衡等压曲线,二、硅氧、锰氧平衡,脱氧反应式：,?,?,?,?,y,x,O,M,O,y,M,x,?,?,平衡常数式：,y,x,m,O,M,1,K,?,?,当脱氧产物为纯氧化物或呈饱和态时，,a,MxOy,1,，,钢液中,M,、,O,活度系数取为,1,，,y,O,x,M,MxOy,m,a,a,a,K,?,?,二、硅氧、锰氧平衡脱氧反应式：?yxOMOyMx?平,y,x,m,O,M,1,K,?,?,取,K,m,的,倒数,，,y,x,O,M,K,?,?,K,称为脱氧常数，用以判断元素的脱氧能力。,元素的脱氧能力：一定温度下与一定浓度的脱氧,元素相平衡的氧含量的高低。,yxmOM1K?取Km的倒数，yxOMK?,?,与一定浓度脱氧元素,M,相平衡的钢液,O,含量愈高，,元素的脱氧能力愈弱。,?,与一定浓度脱氧元素,M,相平衡的钢液,O,含量愈低，,元素的脱氧能力愈强。,?,在,1600,元素含量为,0.1,时，各种元素的脱氧能,力顺序为：,Ca,、,Al,、,Ti,、,B,、,C,、,Si,、,V,、,Cr,、,Mn,依次,减小。,?,随着温度下降，平衡发生移动，使脱氧反应不断,进行,。,y,x,O,M,K,?,?,?与一定浓度脱氧元素M相平衡的钢液O含量愈高，元素的,脱氧反应式,log K,1873K,时的,K,2Al,3O,Al,2,O,3,(s),64000/T,20.57,2.51,10,-14,2B,3O,B,2,O,3,(l),10,-8,Ba,O,BaO(s),10000/T,1.8,7.26,10,-8,C,O,CO,1160/T,2.003,0.00239,Ca,O,CaO(s),8.32,10,-10,2Ce,3O,Ce,2,O,3,7.94,10,-18,2Cr,3O,Cr,2,O,3,44040/T,19.42,8.07,10,-5,Mn,O,MnO(l),12950/T,5.53,0.0413,Nb,2O,NbO,2,(s),32780/T,13.92,0.000262,Si,2O,SiO,2,(s),30110/T,11.40,2.11,10,-5,2Ta,5O,Ta,2,O,5,(s),63100/T,21.90,1.62,10,-12,3Ti,5O,Ti,3,O,5,(s),7.94,10,-17,2V,3O,V,2,O,3,(s),43490/T,17.60,2.40,10,-6,ZrO,2,(s),Zr,2O,57000/T,21.8,2.33,10,-9,脱氧反应式 log K 1873K时的K 2Al3O,硅氧平衡,根据前面所,述计算公式,可求得不同,温度下的硅,氧平衡如右,表：,温度（,）,Si,?,O,2,1580,1.41,10,-5,1590,1.73,10,-5,1600,2.11,10,-5,1610,2.57,10,-5,1620,3.12,10,-5,硅氧平衡根据前面所述计算公式可求得不同温度下的硅氧平衡如右表,锰氧平衡,根据前面所,述计算公式,可求得不同,温度下的锰,氧平衡如右表：,温度（,）,Mn,?,O,1580,0.0348,1590,0.0379,1600,0.0413,1610,0.0449,1620,0.0489,锰氧平衡根据前面所述计算公式可求得不同温度下的锰氧平衡如右表,三、单独元素的脱氧能力,在,1650,、脱氧产物,活度为,1,的条件下，,元素脱氧能力：,Ca Al Ti C,Si V Cr Mn,?,?,?,?,y,x,O,M,O,y,M,x,?,?,三、单独元素的脱氧能力在1650、脱氧产物活度为1的条件下,锰的,脱氧,Mn+O=MnO(l),?,G,?,=,285025,126.84 T,0,0.2,0.4,0.6,0.8,1,1.2,1.4,1.6,1.8,2,0,0.5,1,1.5,2,Mn,%,O,%,1650,?,脱氧能力很低；,?,局部锰含量高，可局,部脱氧；,?,随温度降低，锰脱氧,能力增强；,?,与硅、铝同时使用，,增强硅、铝的脱氧能,力。,锰的脱氧Mn+O=MnO(l)?G?=285025,硅的,脱氧,Si+2O=SiO,2,(s),?,G,?,=,585700,226.86 T,0,0.01,0.02,0.03,0.04,0.05,0.06,0,0.5,1,1.5,2,Si,%,O,%,1650,?,具有较强的脱氧能力；,?,随温度降低，脱氧,能力增强；,硅的脱氧Si+2O=SiO2(s)?G?=5857,铝的,脱氧,2Al+3O=Al,2,O,3,(s),?,G,?,=,1243660,394.7 T,?,非常非常强的脱氧,能力；,?,随温度降低，脱氧,能力增强；,?,为大多数钢种采用。,0,10,20,30,40,50,0,0.02,0.04,0.06,Al,%,O,p,p,m,1650,铝的脱氧2Al+3O=Al2O3(s)?G?=12,0,0.02,0.04,0.06,0.08,0.1,0,0.02,0.04,0.06,0.08,0.1,Al,C,Si,%C,、,%Al,、,%Si,%,O,真空条件下,C,、,Al,、,Si,成分的氧化趋势,00.020.040.060.080.100.020.040,0,0.02,0.04,0.06,0.08,0.1,0,0.001,0.002,0.003,0.004,0.005,Al,C,%C,、,%Al,%,O,00.020.040.060.080.100.0010.00,