电磁制动对薄板坯结晶器内冶金行为的影响

为进一步提高多模5孔块电磁制动系统在高效连铸过程中的应用效果，以某钢厂FTSC薄板坯结晶器以及新型多模块连续电磁制动(MM-EMB)系统为原型，将结晶器内流场特征以及钢渣界面波动程度作为评判标准，采用数值模拟手段对不同电磁条件下的结晶器流场进行多物理场的耦合计算，重点揭示了在6 m/min的高拉速条件下，对电磁制动系统施加不同电流强度时，多模块连续电磁制动系统中不同线圈组合对薄板坯连铸结晶器内流场特征的影响规律。研究结果表明，结合5孔水口的结构特点，电磁制动(MM-EMB)系统依据其作用范围可将5组线圈分为2组控制单元，其中上部控制单元包含2组线圈，主要作用域为钢液流场上回流区域，当2组线圈施加电流由400 A增加到1 000 A时，可以有效降低钢液流股冲击钢渣界面的速度，减小钢渣界面波动；下部控制单元包含3组线圈，主要对结晶器内下回流起稳流作用，当3组线圈电流增大至800 A时，涡心位置和窄面冲击点明显下降，下回流强度和范围得到了有效控制。当将2组控制单元共同作用于结晶器钢液流场，下部控制单元线圈电流为800 A时，上部控制单元2组线圈施加电流取800 A可以达到最佳制动效果。将数值...     

双流低频电磁连铸过程中磁场分布的数值模拟

采用数值模拟的方法研究了双流低频电磁连铸过程中磁场分布规律.建立了单、双流低频电磁连铸中包括铸锭、结晶器、线圈和屏蔽罩的二维轴对称有限元模型.利用ANSYS软件包进行划分网格及计算,模拟出了磁场在连铸结晶器区域的分布.研究了电流频率、电流强度、电流方向和线圈距离对金属熔体内磁感应强度的影响.计算结果表明:单流时,电流频率升高,磁感应强度降低;电流强度增大,磁感应强度升高.双流时,无论电流方向是同向还是反向,同一铸锭的远端磁场强度要大于其近端磁场强度,相邻线圈电流方向为反向时,铸锭内磁场强度高于相邻线圈电流方向为同向的情况;增大线圈之间的距离时,铸锭远端和近端的磁感应强度的差值降低.     

电磁制动对CSP漏斗型结晶器流场和液面波动的影响

针对铸坯断面为1 500 mm×90 mm的漏斗型结晶器,在拉速为5 m/min的条件下,通过耦合湍流模型、多相流模型以及电磁制动模型,计算了电磁场作用下结晶器内流体流动与液面波动特征.数值模拟结果表明,应用电磁制动能显著改变结晶器内钢液流动行为,使结晶器内流场分布更加均匀.此外,当施加的磁场强度为0.2和0.3T时,结晶器最大液面波动高度从未施加电磁制动时的15mm减小至9.2mm和2.33 mm.综合考虑到电磁制动效果与生产成本,合理的磁场强度应控制在0.2～0.3 T.     

电磁搅拌对特大方坯结晶器内流场及温度场影响

以某厂断面为410 mm × 530 mm的特大方坯结晶器为原型,利用ANSYS有限元软件建立三维数值模型,研究电磁搅拌对结晶器流场及温度场的影响。施加电磁搅拌后,钢液受到径向电磁力,液面呈现旋转流动趋势。结晶器内钢液最大切向速度随着电流的增加而增大,随着频率的增加而减小。电磁搅拌的电流大小由0 增加到500 A时,液面波动由1.21 mm增加到4.35 mm。电磁搅拌能够使钢水的高温区局限于连铸结晶器上部,钢水温度更加均匀。同时钢液的水平旋流能够抑制初生坯壳的生长,降低坯壳的生长速度,使结晶器出口处坯壳厚度变薄。综合分析,该厂在实际生产时合理的电磁搅拌的电流大小应为400 A,频率为1.5 Hz,此时钢渣液面波动约为2.73 mm,温度场较为均匀。      

Φ150 mm圆坯结晶器电磁搅拌数值模拟研究

以结晶器电磁搅拌器为研究对象,建立了Φ150 mm断面结晶器电磁搅拌过程的电磁场与流场耦合的三维数学模型,并采用有限元软件进行求解。分别模拟不同条件下的结晶器电磁搅拌电流和不同电磁搅拌频率作用下钢液在结晶器内流动状态的规律。研究结果表明:随搅拌电流的增大,钢液的切向流速增加,上部环流区缩短,下部旋转流动区域上移并扩大,搅拌电流和频率对钢液流动的影响相反;在电磁搅拌过程中,电磁搅拌使结晶器内钢液产生旋转流动阻止过热钢液下移,减弱冲击深度,使热区明显的上移。     

圆坯连铸结晶器电磁搅拌数学模拟

用数学模拟对马钢一钢厂圆坯连铸结晶器(断面尺寸为φ450mm)电磁搅拌过程进行了研究,找出变化规律,确定合理的工艺参数,优化结晶器流场．电磁搅拌过程的计算结果表明：磁场强度随搅拌频率减小、搅拌电流增大而增大;电流强度不改变磁场分布;在结晶器高度方向上磁场分布呈现中间大两端小的特征,流场在搅拌力作用下更趋于合理．最佳搅拌工艺参数为：搅拌电流350A,频率2Hz．     

GCr15钢大方坯结晶器电磁搅拌工艺参数优化研究

摘要：为明确不同电磁搅拌条件对结晶器内钢液流动、传热行为的影响规律,对现场大方坯连铸结晶器电磁搅拌工艺参数的配置提供依据,采用ANSYS Fluent及Maxwell研究了320mm×280mm断面GCr15高碳轴承钢连铸过程中结晶器电磁搅拌工艺参数对结晶器内钢液温度场、磁场特性、注流冲击深度及液面波动的影响规律。研究结果表明,在M-EMS作用下,结晶器内钢液温度的耗散明显优于无电磁场作用工况,有利于改善结晶器内温度均匀性。注流的冲击深度随电流强度的增大而降低,而频率改变对钢液冲击深度影响不明显。当电磁搅拌电流强度一定时,随着搅拌频率增加,液面波动趋于平缓;当搅拌频率一定时,随着电流强度增加,液面波动变剧烈。对于320mm×280mm断面GCr15高碳轴承钢不同工艺进行工业试验,只改变结晶器电磁搅拌参数,从300A/2Hz调整到350A/3Hz,铸坯横截面中心碳偏析指数从1.06降低到1.01,铸坯纵截面中心碳偏析指数的平均值从0.98升至0.99,适合该钢种结晶器电磁搅拌工艺参数为350A/3Hz。     

跨结晶器电磁搅拌器磁场特性测试和分析

对 2 8 0mm× 3 80mm方坯连铸机跨结晶器电磁搅拌器进行了在线静态磁场测试 ,通过测试结果分析得出 ,在制订搅拌工艺时 ,应根据结晶器内外磁场强度的差别 ,选择合适的电流强度 ,以提高搅拌效果和搅拌线圈的使用寿命。     

连铸结晶器内电磁制动过程的数值模拟

电磁制动的磁场分布与电磁制动的冶金效果密切相关，建立了描述连铸结晶器内电磁制动过程的三维数学模型，在交错网络下利用半隐式压力校正算法求解了动量方程和感生电流方程，研制了带形电磁制动结晶器内的磁场和流场，并将计算机结果与实测值进行了比较，结果表明，合理的电磁制动磁场强度为0.04～0.24T。     

圆坯中频电磁软接触连铸结晶器内磁场分布数值模拟

 用数值模拟方法研究了圆坯中频电磁软接触连铸结晶器内磁场分布,讨论改变结晶器结构参数、工艺参数和电参数等因素对结晶器内磁场的影响。结果表明,结晶器内磁场强度在结晶器高度方向上先增大再减小,在感应线圈中心偏下处,磁感应强度达最大;综合考虑结晶器结构和透磁性,切缝宽度选为05 mm,切缝数为8;当自由液面位于感应线圈的中心位置时能获得最大的磁感应强度;随着电流和频率的增加,结晶器内磁感应强度也随着增加。     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.     

Seven Rare Earth Projects Involving Close to 3 Billion Yuan Investment Landed In the HighTech Zone

正On May 22,Baotou Rare Earth Industry Cooperation Consultation MeetingProject Agreement-signing Ceremony was held in Ningbo,nearly 40 enterprises from Ningbo,Guangdong,Hunan,and Shanxi participated in project consultation.After multi-lateral communication,agreements were signed for a total of 7 rare earth projects successfully.