钢轨钢生产中硫的控制

 钢轨钢对钢水洁净度和非金属夹杂物控制均有较高要求。针对高硫铁水冶炼现状,为实现钢轨钢的洁净生产,攀钢在铁水预处理、转炉冶炼、钢水精炼方面进行了硫控制技术的开发与应用,形成了提高钢的洁净度和控制钢中非金属夹杂物的数量和形态的洁净钢生产工艺技术,实现了350km/h高速铁路用钢轨的生产。高速轨成品w(［S］)≤0.008%的合格率达到95%以上,钢轨w(T［O］)降至0.001 5%以下,夹杂物的分布形态得到有效控制。     

150 t BOF-LF-VD-CC流程无铝脱氧工艺高速轨钢冶炼过程的夹杂物行为

时速350 km高速钢轨要求钢中全氧含量T[O]≤20×10^-6,非金属夹杂物B、C、D类≤1.0级。国内在重轨钢冶炼中,通常采用无铝脱氧工艺,即采用SiCaBa合金强化脱氧,形成了低熔点的Mn-Al-Si-Ba-Ca多元型氧化物夹杂,该类夹杂物在精炼中全部排出钢液。研究了铁水预处理脱硫-150 t顶底复吹转炉-LF-VD-280 mm ×380 mm连铸流程冶炼钢轨钢U71MnG时的夹杂物行为,包括无铝脱氧工艺钢轨钢中氧化物夹杂的组成及特征,转炉终点[C]对钢水氧活度的影响以及LF精炼渣碱度和VD后期软吹氩搅拌对钢氧含量和夹杂物的影响。结果得出,钢轨头部的≤20μm氧化物夹杂为精炼时二次脱氧产物,通过控制转炉终点[C]＞0.15%,控制精炼渣碱度(CaO)/(SiO₂)=2.5~3,∑(FeO+MnO)≤1.0%可有效降低钢轨钢中氧化物的数量和尺寸。     

350km／h高速轨钢非金属夹杂物控制

夹杂物对高速轨钢的质量有重要影响，考虑到可接受的较低夹杂物百分比要求以及其成为攀枝花钢铁（集团）公司大规模生产350km／h高速轨钢需求的限制环节，研究了350km／h高速轨钢的非金属夹杂物控制技术。优化了钢包炉（LF）吹氩模型、钢包渣组成的控制，并且提出了钢水的钙处理技术。利用所研究的技术，增加了夹杂物的去除比率，重轨钢中夹杂物的组成、分布和形态发生了变化，结果导致平均全氧量减少到10．17×10^-6，非金属夹杂物综合可接受的百分比从48．21％增加到98．1％。试验结果表明该冶金工艺可满足攀枝花钢铁（集团）公司大规模生产350km／h高速轨钢的需求。     

重轨钢非铝脱氧工艺研究

介绍了攀钢重轨钢非铝脱氧工艺，在满足钢中脆性夹杂物控制的前提下，采取“预脱氧＋终脱氧”的工艺，达到钢液脱氧良好，钢轨内部质量大幅提高，钢轨T[O],[Al]及氧化物夹杂评级完全满足200km/h高速铁路钢轨标准的要求。     

350Km/h高速轨用钢的关键冶金技术研究

350 Km/h高速轨对铸坯洁净度以及质量提出更高的要求,本文主要讨论了提高攀枝花钢铁集团公司350 Km/h高速轨用钢洁净度以及铸坯质量的技术方法。通过采取一系列集成创新技术,象BOF脱磷、钢包精炼、结晶器电磁搅拌以及动态轻压下、脱磷率、洁净度以及形态控制等方面得到了很大提升。成分满足[S]≤0.015%,[P]≤0.025%,[H]≤1.5×10~(-6),Als≤0.004%,T[O]≤20×10~(-6),铸坯中心疏松和偏析≤1.0,中心裂纹和中间裂纹≤0.5,中心碳偏析指数≤1.05,A类和B类夹杂物控制水平分别≤2.0和1.0,优化后的工艺满足生产350 Km/h高速轨用钢技术需求,并且实现了稳定生产。     

转炉--CAS--连铸工艺生产低碳铝镇静钢中非金属夹杂物的研究

采用添加示踪剂方法研究了转炉— CAS精炼—连铸工艺生产的低碳铝镇静钢中的非金属夹杂物 ,发现出钢或 CAS精炼过程钢包炉渣与钢液作用生成的夹杂物 ,其中尺寸在 30 μm以下的夹杂物很难从钢液中完全上浮排除。铸坯中主要的非金属夹杂物为来源于钢包炉渣与钢液作用生成的球形夹杂物、块状 Al2 O3夹杂物和簇群状 Al2 O3夹杂物。连铸坯 T[O]在 ( 1 4～ 1 7)× 1 0 - 6之间 ,非金属夹杂物含量在 2 .3mg/ 1 0 kg左右 ,表明该工艺可以生产较高洁净度的低碳铝镇静钢铸坯。     

提高低合金钢钢水质量的研究

结合攀钢实际情况,在生产低合金钢时,出钢过程向钢包内加入高碱度精炼渣,出钢后加入调渣剂,并在LF炉补加少量高碱度精炼渣和0.30～0.60 kg/t铝丸;以及将精炼后钢包底部软吹氩时间延长至6 min以上,改善了钢中夹杂的去除条件,大幅度提高了钢水质量,钢中T[O]平均为14.69×10-6,[S]平均为0.007%,[N]＜50×10-6,非金属夹杂中B、C类夹杂较少,A、D类夹杂多为0.5级.     

帘线钢精炼工艺技术研究

针对高品质帘线钢对钢中夹杂物组分及钢液洁净度的严格要求,系统地开展了钢包顶渣组成和精炼工艺流程的研究。理论研究结果和生产实践表明,精炼过程将钢包顶渣二元碱度(CaO/SiO_2)控制在1.0左右,渣中Al_2O_3含量控制在6%~8%,可以将夹杂物基本控制在低熔点塑性区域;与De S-LD-LF-Ar-CC工艺相比,采用De SLD-LF-RH-CC生产工艺可以在实现夹杂物塑性化转变的同时进一步降低钢中T[O]、[N],提高钢液洁净度。所生产的帘线钢吨钢断丝率平均为0.47次/t,疲劳寿命在2万次以上。     

高洁净度汽车用非调质钢中非金属夹杂物研究

对ω(T[O])低于0.0010%高洁净度非调质钢中非金属夹杂物进行了研究.发现在LF精炼中,由于采用高碱度炉渣和强扩散脱氧,钢液中铝脱氧生成的含较高Al2O3的夹杂物向镁、钙铝酸盐类夹杂物转变.经VD处理钢液ω(T[O])降低至0.0010%以下后,在钢水试样中已很少观察到氧化物类夹杂存在.在高洁净度非调质钢中存在许多复合夹杂物,中心部位为MnS,而边缘部位为在较低温度下依附在已生成的MnS类夹杂物上析出的TiN等.     

关于钢洁净度指数的讨论

首先从高品质钢的洁净化、精准化、均质化和细晶化四个方面引申出了钢中非金属夹杂物的问题,阐述了"非金属夹杂物不是钢的所有问题,但所有钢都有非金属夹杂物的问题"、"非金属夹杂物是钢的天然成分,可以通过研究非金属夹杂物的生成机理来确定其控制方略,进而改善钢的质量"等重要观点。讨论了总氧含量(T.O)作为钢洁净度指数的不足之处,进而提出了钢的洁净度指数(I_c=xT.O+y(Al_2O_3)),即对于铝脱氧钢,式中y为零,夹杂物的控制主要强调钢中T.O含量要低;对于硅锰脱氧钢,式中x为零,夹杂物的控制主要强调夹杂物中的Al_2O_3含量要低。基于此洁净度指数,总结了多种钢的洁净度和非金属夹杂物的控制目标。文中还讨论了稳态浇铸与非稳态浇铸对钢洁净度的影响,提出了钢水洁净度水平最好的情况是非稳态持续时间短,且钢中非金属夹杂物控制水平好。最后讨论了钢中非金属夹杂物数量和个数表征的几个经典问题,包括如何计算夹杂物的平均含量和平均尺寸、夹杂物尺寸组的大小和数量的关系、如何把二维的夹杂物尺寸分布结果转化为三维的结果。     

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.