中间包涂料对钢液洁净度的影响

实验研究了镁质、氧化铝质和镁钙质三种中间包内衬涂料与钢水反应,考察了其对钢中T.O, T.N及Al, Ti, Si, Mn含量、夹杂物组成、数量和尺寸分布的影响,并分析了钢水在钢/涂层界面对涂层的渗透和侵蚀程度. 结果表明,在1550℃下,相比于镁质涂料和氧化铝涂料,镁钙质涂料能对钢液T.O和成分有更好的控制,终点氧含量在8.5′10-5,对钢液的二次氧化很少,并有利于细小夹杂物的形成,其中<1 mm夹杂物占98.13%;钢中首先是Al, Ti被氧化,之后是Si, Mn被氧化;氧化铝涂料被损坏的机理主要是冲刷脱落,镁质和镁钙质涂料的损坏则以渗透侵蚀为主. 镁钙质涂料对钢液的二次污染小,有利于洁净钢的生产.     

酒钢CSP流程SPCC钢夹杂形成机理

对酒钢CSP流程SPCC两个浇次在LF进站、LF中期、LF出站、中包、铸坯和轧制过程分别取钢样,用SEM-EDS分析其夹杂物及成分. 结果表明,在喂铝线后,钢液中很快形成大量形状不规则Al2O3夹杂物,随着精炼进行夹杂物存在两种变性路线：Al2O3-MgO·Al2O3-CaAlMg复合夹杂物和Al2O3-CA6-CA2-CA-低熔点夹杂物. 经过钙处理后大部分夹杂物可较好地变性到低熔点液相区或固液两相共存区. 夹杂物变性越好,则钢液中夹杂物球形化率越高,总量也越小,夹杂物成分对其尺寸也有重要影响. 分析了外层被钙铝酸盐和CaS包裹的双层夹杂物的形成机理,前者由于钢中Ca还原MgO·Al2O3尖晶石中Mg或Al2O3中Al;后者由于在铸坯凝固过程中温度降低及元素S的偏析,造成液芯中S浓度升高,其与Ca在已有的固体夹杂物核心的表面析出CaS. 在轧制过程中,前者变形能力较好,后者的外层CaS易与内部核心分离,甚至产生微裂纹.     

中间包结构及包衬耐火材料对钢水清洁度的影响

通过中间包砌筑结构的变化,分析了钢水内不同级别的颗粒夹杂物上浮的机率;又通过中间包内渣层中示踪剂的变化,分析了包衬耐火材料在单炉钢水冲刷下的侵蚀量,从而定量判定了中间包结构及包衬耐火材料侵蚀对钢水清洁度的影响程度。     

Consteel-LF-VD-CC生产55SiMnMo钢种的洁净度研究

针对贵钢在使用55SiMnMo中空钢实心坯制造的钎杆出现因硬性夹杂导致断裂的问题,对55SiMnMo中空钢生产工艺Consteel-LF-VD-CC进行全流程取样,对钢中气体含量和夹杂物进行分析,找到钢水洁净度的限制性环节,并由此得出改进措施. 钎杆断裂面的夹杂物分析显示,主要为较大粒径的带棱角的纯Al2O3硬性夹杂以及不规则形状的MgO-CaO-SiO2复合夹杂. 分析钢样可发现以下工艺问题：LF精炼后期渣面裸露吸气,钙处理后夹杂物变性不完全,钢包开浇过程中存在明显吸气和卷渣现象. 铸坯中T[O]含量为9×10-6,显微夹杂物以MnS, Al-Mn的复合氧化物夹杂为主,大型夹杂物以SiO2-Al2O3-MnO-CaO复合夹杂为主.     

电渣重熔过程结晶器旋转对钢中夹杂物的影响

基于自行设计的双极串联结晶器旋转电渣重熔炉,采用ASPEX全自动夹杂物分析仪研究了结晶器转速对M2电渣锭洁净度的影响。结果表明,不论结晶器是否旋转,电渣锭中的夹杂物组成基本不变,主要由Al2O3, Al2O3–MnS, Al2O3–SiO2–CaO–MnS, MgO–Al2O3–SiO2–CaO–MnO, MgO–Al2O3–SiO2–CaO–TiO2–MnS, Al2O3–SiO2–CaO–MnO–TiO2组成,其中以Al2O3, Al2O3–SiO2–CaO–MnO–TiO2和Al2O3–MnS数量最多。结晶器静止电渣重熔时,钢中的夹杂物数量较多,且存在50 ?m以上的大颗粒夹杂物,而结晶器转速为6和13 r/min时,夹杂物数量减少,大颗粒夹杂含量大大降低;转速增至19 r/min时,夹杂物数量及尺寸又进一步增加,同时钢中全氧含量、氮含量明显增加。电渣锭中大颗粒夹杂物得以去除的主要原因是结晶器旋转导致金属自耗电极末端的熔融层变薄、熔滴尺寸变小,渣–金接触面积增大,促进了夹杂物被熔渣去除;过快的转速会增加自耗电极氧化、减少渣–金接触时间,从而降低电渣重熔过程的精炼能力。     

钙质中间包覆盖剂的研制与应用

通过添加适当的稀释剂、引气剂和保气剂 ,优化覆盖剂的组成、粘度、熔化温度和熔化速度 ,研制出的钙质中间包覆盖剂自由碳含量低 ,在使用过程中粉尘少、不结壳、不挂渣 ,铺展性能和保温效果好。使用该覆盖剂后 ,中间包渣中SiO2 、Al2 O3、S、MnO的含量大幅度增加 ,说明该覆盖剂对钢液中的SiO2 、Al2 O3、S、MnO等夹杂物具有极强的吸附作用 ,可起到净化钢水、提高钢坯质量的冶金效果     

铝镁尖晶石炭钢包砖的研制

在高铝质材料基质中加入MgO粉,并添加适量的碳素材料及抗氧化剂,研制出了铝镁尖晶石炭钢包砖。该铝镁尖晶石炭砖质量稳定,在太钢第二炼钢厂70t钢包上使用两年多来,包龄基本上稳定在75次左右,并且使用过程中侵蚀均匀,与打结包相比,挂渣少,无剥落。     

不锈钢渣理化性质分析与应用研究

借助于XRD、SEM和DSC/TG等测试分析手段进行不锈钢渣理化性质分析与表征.结果表明:不锈钢渣化学成分主要是SiO2和CaO,其次是MgO、Al2O3及Fe2O3;矿物组成包括硅酸三钙(Ca3SiO5)、硅酸二钙(Ca2SiO4)、硅钙石(Ca3Si2O7)、硅酸钙(CaSiO3)及RO相;微观结构由许多尺寸大小不等的颗粒组成,孔隙大、结构疏松;内外照射指数IRa和Iγ均小于1.0,符合GB 6566-2010标准;当不锈钢渣质量百分比掺量为30%时,28 d抗压强度基本达到P· C32.5复合硅酸盐水泥标准,且7 d活性指数显著高于28 d活性指数.并依据研究结果分析不锈钢渣在水泥、混凝土及建筑材料领域资源化利用的可行性.     

Properties and Application of Slide Nozzle Plate for High Oxygen Steel

Several kinds of slide nozzle plate such as Al2O3-C-ZrO2,MgO,Al2O3,Spingel-C and Al2O3-C SN plate for high oxygen steel used in BaoSteel have been analysed,the appearance and size of the SN plate after using have been measured.The Al2O3-C SN plate has longer service life in casting high oxygen steel,and the wear mechanism of different SN plates is discussed.     

Effect of magnesia-calcium hexaaluminate refractories on the quality of low-carbon alloy steel

High-performance alloy steel is distinguished by its purity. Inclusion contamination and oxygen addition to the steel due to long contact between the refractories of the tundish and the steel should be avoided. In this study, the static crucible method was used in the interaction experiments between MgO–CA₆ composite and low carbon alloy steel. The effects of different proportions of MgO–CA₆ on the content of alloying elements in steel were analyzed. Morphology, quantity, size, and distribution of inclusions were also examined. The results indicated that more inclusions (e.g., MnO, FeO, and MnS) were generated between the MgO material and alloy elements (e.g., Fe and Mn) in molten steel. The oxygen content in molten steel of CA₆, MgO–0.28CA₆, and MgO–0.70CA₆ materials, as well as the number of inclusions, were sharply reduced. The particle size was smaller, resulting in good molten steel purification ability. The oxygen content of the steel in contact with the MgO–0.28CA₆ material was relatively low, characterized by a reduction in the proportion of inclusion area and particle.     

Experimental Study on Composition Optimization for Refining Slag Containing BaO

Laboratory study was carried out on deep desulfurization of molten steel by CaO-Al2O3 based refining slag containing BaO at 1873K to achieve lower sulphur level in steel. A mathematical model of desulfurization was established with the methodology of quadratic orthogonal regression. According to the modle, the influence of Al2O3/CaO, MgO, CaF2, BaO in slag on desulfurization rate was analyzed. The results showed that the desulfurization rate almost linearly decreased with the increase of Al2O3/CaO, and it increased firstly then decreased when MgO and BaO content increased respectively, yet the trend is on the contrary as CaF2 content increased.Based on the comprehensive analysis, the optimum composition of the refining slag was achieved under the experimental conditions.     

超低碳铝硅镇静钢精炼过程中夹杂物的行为及其对钢组织的影响

针对RH精炼并结合典型的渣-钢化学平衡实验,研究了超低碳铝硅镇静钢精炼过程中夹杂物的变化以及钢包顶渣组成对钢中夹杂物的影响. 用激光共聚焦高温扫描显微镜在线观察了再加热过程中钢的微观组织变化,讨论了夹杂物对钢的晶粒长大的影响. 结果表明,本实验条件下精炼前钢中夹杂物是以Fe-Mn氧化物为主的复合夹杂,夹杂物数量和大小受渣碱度、Al2O3含量及CaO/Al2O3比值的影响较大,当碱度为1.5及Al2O3含量为20%时,夹杂物数量最少. 以成分优化的钢包渣与精炼末期钢样进行的平衡实验显示,夹杂物为Al2O3-MgO或Al2O3-MgO-SiO2-MnO为主的复合夹杂,随渣中w(MnO)的增加,复合夹杂中Mn含量有增加的趋势,使钢的晶粒长大过程需要更高的再加热温度. 钢样再加热后,钢中夹杂物变为以Al2O3, MgO, SiO2复合夹杂为主,三者总量占夹杂物总量的90%或以上,复合夹杂中MnO含量受加热制度影响.     

电炉用镁尖晶石质捣打料的研究与应用

分析了目前电炉炉底用MgO-Fe2O3-CaO质捣打料化学矿物组成及使用现状,针对钢厂电炉冶炼操作条件的变化,开发出了新一代的镁尖晶石质电炉炉底捣打料。对体积稳定性、烧结性、耐高温性、抗渣性及显微结构分析后,并通过钢厂实际试用表明：镁尖晶石质耐火材料在使用过程中发生MgO＋Al2O3→MgO.Al2O3反应,伴随膨胀使材料自身过烧收缩受到抑制,减轻或避免了炉底的开裂剥落,明显提高了炉底寿命。     

Wettability of tundish periclase lining by steel

Results of a study of the wettability of the tundish periclase lining by molten steel using a sessile drop method are presented. The wetting angle θ tends to decrease with increase in temperature and contact time on adding glass fiber and Fe₂O₃ powder in excess of 2% to the magnesite powder; a similar effect is observed in steels high in manganese. An increase in angle θ is observed on adding carbon fiber or glass fiber (not in excess of 1%) to the magnesite powder; the angle θ tends to increase with increase in MgO powder grain size and with carbon contained in steel in excess of 0.04%. __________ Translated from Novye Ogneupory, No. 1, pp. 63–68, January, 2006.     

燃煤飞灰化学成分随粒度分布规律的试验研究

在对国内几家电厂电除尘器收集的燃煤飞灰进行混配、筛分及全灰化等处理后，采用常量法对分电场、分粒径灰样的化学成分进行了分析。结果发现：飞灰中SiO2,Al2O3,TFeO,CaO和MgO等化学成分的含量随电场及飞灰的粒度呈一定规律分布，Al2O3含量则随着粒度的减小而逐渐增加，CaO和MgO的含量随粒度变细也有增加的趋势，针对造成这种分布规律的机理进行了初步的分析。     

内弹道稳定剂对中高燃速RDX-CMDB推进剂燃烧性能的影响

以一种中高燃速改性双基推进剂配方为基础配方,添加不同粒度的Al_2O_3及不同品种的内弹道稳定剂,研究了6~20MPa下推进剂燃速和燃速压强指数的变化规律,并对其燃烧机理进行了分析。结果表明,添加Al_2O_3后推进剂的燃速降低,且随着压强的升高,燃速降低的幅度减小;不同品种的内弹道稳定剂对燃速及燃速压强指数降低和提高的幅度不同,TiO2提高了推进剂高压段的燃速,MgO几乎不影响推进剂燃速,而Al_2O_3、ZrO_2均降低了推进剂的燃速。添加不同粒度的Al_2O_3后,均使燃烧表面的催化剂含量(浓度)降低,改变了催化剂的催化效率,从而导致添加芳香铅A催化剂的推进剂中Al_2O_3粒径分别为10μm和2.5μm时,燃速相应降低0.25mm/s和1.25mm/s。不同品种的内弹道稳定剂对燃烧表面催化剂含量、分散均匀性、催化活性的影响不同,TiO_2、MgO的活性高于Al_2O_3和ZrO_2,从而表现出添加TiO_2、MgO的推进剂燃速高于添加Al_2O_3、ZrO_2的推进剂。     

不同氧化物对磷酸盐玻璃结构与性能的影响

在化学组成为40Na 2O·60P2 O 5的基础上,用CaO、MgO取代Na 2O或用Al2 O 3、B 2 O 3和SiO2取代P2 O 5制备5种磷酸盐玻璃体系,用X射线衍射(XRD)和傅立叶变换红外光谱(FTIR)对玻璃结构进行了表征,并测定了该玻璃体系样品的密度、化学稳定性等基本性质。研究发现,用CaO取代Na 2O和Al2 O 3取代P2 O5可以显著改善玻璃的化学稳定性;用SiO2取代P 2 O 5时,玻璃的化学稳定性下降;由于配位问题,B 2O 3和MgO对磷酸盐玻璃结构与性能的影响出现转折点。     

Experimental Study Refining on Composition Slag Containing Optimization for BaO

Laboratory study; was carried out on deep desulfurization of molten steel by CaO-Al2O3 based refining slag containing BaO at 1873K to achieve lower sulphur level in steel. A mathematical model of desulfurization was established with the methodology of quadratic orthogohal regression. According to the modle, the influence of AlO3/CaO, MgO, CaF2, BaO in slag on desulfurization rate was analyzed. The results showed that the desulfurization rate almost linearly decreased with the increase of Al2O3/CaO and it increased firstly then decreased when MgO and BaO content increased respectixely, yet the trend is on the contrary as CaF2 content increased. Based on the comprehensive analysis, the optimum composition of the refining slag was achieved under the experimental conditions.     

镁质挡渣墙的研制、生产与应用

以高纯烧结镁砂和电熔镁砂为主要原料研制出了具有良好物理性能、施工性能、抗爆裂性能和使用性能的挡渣墙用镁质浇注料。探讨了养护温度、养护时间和环境湿度对坯体性能的影响。在某钢厂 4 8t中间包中的实际使用结果表明 ,镁质挡渣墙对钢水中CaO、SiO2 和A2 O3夹杂物具有明显的吸附作用     

碳酸钠焙烧铝系钒铁炉渣共提取钒与铝

通过对铝系钒铁炉渣碳酸钠焙烧-水浸全过程的矿物分析、热力学计算及对比实验,研究了炉渣中钒、铝同步转化、溶出的机理与规律. 结果显示,焙烧进程中渣中镁铝尖晶石MgO×Al2O3相、CaO×2Al2O3相逐渐消失,MgO相生成,并生成碱熔相Na2O×Al2O3和钒酸盐. 随焙烧温度及时间增加,Na2O×Al2O3和钒酸盐相明显增多,钒、铝溶出率增加. 焙烧熟料经水浸后,液相呈碱性,钒、铝分别以可溶性钒酸钠和铝酸钠的形式进入水相,固相残留物为少量未反应的镁铝尖晶石及新生成的MgO和Ca(OH)2. 在磨矿粒度<75 mm、配碱系数1.0、焙烧温度1000℃及焙烧时间4 h的优化条件下,钒的溶出率可达90%,铝的溶出率可达75%.