板坯连铸结晶器非稳态流场的模拟研究

本文运用数值模拟研究方法,研究高拉速厚板坯连铸非稳态结晶器流动特性,研究浸入式水口堵塞、水口不对中对结晶器流场、液面流速和对初生坯壳的影响。高拉速厚板坯连铸,铸坯质量下降,90%表面缺陷集中在铸坯边角区域,最严重的缺陷是铸坯中心和角部纵裂。非稳态工况对结晶器的流场影响因素更为显著,研究发现水口堵塞程度、水口出口流速、流量分配比是结晶器液面流速不对称、液面波动的主要影响因素,水口不对中是钢液流股对结晶器初生坯壳局部热冲击的主要因素,因此高拉速连铸应尽量避免非稳态工况操作,确保产品质量和效率的双赢。     

天钢板坯结晶器流场物理模拟及连铸工艺优化

为研究结晶器内钢液流场,通过对工艺参数的优化,进一步提高铸坯质量,以天津钢铁集团有限公司4#-VAI板坯连铸结晶器为原型进行水模试验,通过调节拉速、水口浸入深度,研究了结晶器内流场形态、液面波动、流场冲击深度和保护渣形貌等的变化情况。模拟试验表明,在现有参数和水口尺寸情况下,结晶器流场合理、液面渣层平稳、坯壳厚度均匀,能够满足铸坯质量要求。     

高拉速板坯连铸结晶器液面波动影响因素研究

应用CFX软件,模拟高拉速板坯连铸结晶器流场和液面波动,计算F数,研究了拉速、结晶器规格、水口参数、结晶器吹氩等因素对结晶器液面波动的影响。通过与F数对比,各因素对结晶器液面波动影响态势与F数基本一致。高拉速下,最佳F数值为3～5,此时结晶器液面波动小且平稳,结晶器液面钢液中心线流速为0．05～0．1m／s。     

板坯连铸结晶器内液面波动的水模型研究

以某厂板坯连铸结晶器为原型,采用1:1的水模型进行试验,以瞬时波高为判断依据,研究了拉速、浸入式水口出口角度、水口浸入深度、水口底面结构等工艺参数对板坯结晶器内流场和液面波动行为的影响.提出了优化结晶器流场的工艺参数,为在实际生产中减少结晶器内卷渣提供了依据.结果表明:拉速对板坯连铸结晶器内液面波动的影响最大,水口倾角...     

板坯连铸浸入式水口浸入深度对卷渣行为的影响

板坯连铸中,浸入式水口浸入深度对保护渣卷入有着非常重要的影响.针对某厂板坯结晶器流场、钢液表面流动情况展开研究,通过数值模拟对不同浸入水口浸入深度进行对比分析,并采用水模型试验进行验证.结果表明,浸入深度为100 mm和110 mm时,结晶器液面表面流速较高,最高分别为0.215 m/s和0.210 m/s;浸入深度为...     

凝固坯壳对高拉速板坯连铸结晶器钢水流动特征的影响

 采用全比例的水力学模型,利用刺激-响应法、波高传感器、流速仪研究了考虑凝固坯壳时高拉速板坯连铸结晶器内的钢水流动、液面特征与卷渣特征。结果表明：考虑凝固坯壳后钢液到达液面的时间缩短;在高拉速条件下(2.4 m/min), 有坯壳时结晶器液面最大平均波高与表面流速比没有坯壳时分别大31 % 和17.5 %,使卷渣更容易发生。其主要原因在于考虑坯壳后结晶器下部钢液的自由流动空间变小,下回流的钢液流动受到抑制,上回流的能量变大。所以在高拉速结晶器水模拟试验过程中,有必要考虑凝固坯壳的影响。     

厚板坯连铸结晶器流场数值模拟

针对鞍钢新轧钢第一炼钢厂厚板坯连铸结晶器建立了三维湍流数学模型和三维实体模型.应用有限元软件对厚板坯连铸结晶器内的流场进行了模拟,计算了铸机拉速、浸入式水口出口倾角和水口浸入深度等工艺参数对结晶器内钢液流动的影响.对比表明,数值模拟结果与水模实验结果相符.     

基于PIV技术的板坯连铸结晶器内钢水流动行为研究

利用粒子图像测速技术,以200 mm×2040 mm板坯连铸结晶器为原型,建立1∶4水模型进行实验,对结晶器内钢液流动形态、流速及各流态所占比例、液面波动、以水口为中心结晶器两侧对称点速度随时间的变化、水口两侧液面水平流速、水口两侧对称位置液面至结晶器底部垂直方向速度和钢液对两侧窄面的冲击深度进行系统地研究和分析,并对比拉速的影响.研究表明,粒子图像测速技术不仅可以测量结晶器内流场流速,还可以对流场对称性进行全方位、多角度定量分析,为研究连铸参数变化,比如拉速、水口结构和水口浸入深度,对板坯连铸结晶器内钢液流动及对称性的影响提供一种较为精确的方法和思路.通过分析得出,在本实验条件下拉速0.5 m·min-1优于0.6 m·min-1.      

475 mm特厚板坯连铸结晶器浸入式水口优化数值模拟研究

特厚板坯连铸技术主要应用于特种装备制造领域,市场需求量较大。浸入式水口的结构是决定结晶器中流场流动行为的关键因素。本研究通过建立三维数值模型,研究浸入式水口侧孔倾角对475 mm特厚板坯结晶器内流场流动行为、温度场和凝固坯壳分布的影响。结果表明,水口侧孔倾角对钢液流动行为影响显著：当侧孔倾角由-20°调整至-10°时,射流冲击深度由660 mm减小至545 mm,结晶器自由液面平均温度升高4 K;此外,侧孔倾角的减小使凝固坯壳尤其是窄面坯壳厚度增加6 mm。综合考虑,当水口侧孔倾角为-10°时,结晶器性能最佳,此时的液面流动较活跃,结晶器保护渣和液面之间的传热性良好,出口处的壳体厚度均匀,足以满足生产需要,可有效避免漏钢现象发生。     

结晶器内钢液面波动分析与控制

通过水模试验对邯郸钢铁集团有限责任公司邯宝炼钢厂连铸结晶器液面波动原因进行分析。结果表明,随着板坯连铸机拉速提高、吹氩量增加、铸坯断面的增加,结晶器钢液面波动量增大;随着浸入式水口浸入深度增加和水口出口角度增大,结晶器内钢液面波动量减小。选择合适的拉速、恒速浇铸、优化浸入式水口形式和浸入深度、保持适当的吹氩量、执行标准化操作,可以降低结晶器钢液面波动量,提高连铸坯质量。采取优化措施后,结晶器钢液面波动量逐渐恢复到±3 mm以内,热轧卷板边部翘皮和夹杂缺陷比例逐月降低,缺陷率从2010年11月0.41%控制到2011年4月以后0.1%以下。     

熔炼次数对M17返回料合金成分、组织和性能的影响

实验结果表明,M17铸造高温合金(%:0.16C、8.79Cr、5.79A1、4.93Ti、3.29Mo、15.20Co、0.78V、0.015B、0.073Zr、0.002S、0.001P、0.001 1O、0.001 0N)经25 kg真空感应炉返回重熔后,Si含量随重熔次数的增加而略有增加,合金中主要元素和其它杂质元素S、P、H的含量变化不大,而氧、氮略有增加;合金中初生碳化物由新合金中的草书体逐渐向返回合金块状转变,初生碳化物的遗传性堵塞合金凝固时的补缩通道,使返回料合金的疏松倾向增大,高温塑性下降较大。     

China's Major Non-ferrous Metals Imports & Exports

正~~     

Zinc Production by Province in 2014

正~~     

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.