电炉冶炼低钛轴承钢工艺实践

在电炉冶炼中通过氧化去除钢水中的残余钛,使出钢终点w(Ti)≤0.001 0%,精炼过程中使用低钛合金、造渣料、辅助材料等使精炼渣碱度控制在4~6,精炼过程的钛增幅≤0.001 2%,钢中成品w(Ti)≤0.003 0%,可提高轴承的疲劳寿命。     

马氏体不锈钢冶炼质量优化

通过工艺改进和AOD的使用,基于不锈钢冶炼过程的“脱碳保铬”原理,结合AOD冶炼工艺优化,获得高质量钢水成分为:w(C)=0.02％～0.04％、w(Si)=0.49％～0.53％、w(Mn)=0.60％～0.69％、w(Cr)=12.90 ％～13.57％、w(Ni)=3.95 ％～4.34％、w(S)≤0.015％、w(P)≤0.028％、w(O)≤80×10-6、w(N)≤150×10-6、w(H)≤3×10-6,并使球状氧化物评级不超过2.0.新工艺大幅提高了马氏体不锈钢的钢水洁净度,满足了熔炼成分及各项理化指标的要求.     

LF-RH生产超低碳钢种生产实践

超低碳钢种生产成分要求w(C)≤0.015 0%。传统RH生产超低碳钢种工艺多采用RH—连铸单联工艺路线生产超低碳钢工艺稳定性差,生产不稳定。本文根据日钢实际生产情况,介绍一种新型生产工艺,通过LF-R H工序的工艺优化、关键点控制,对成分、钢水可浇性等方面进行攻关,成功试验LF-R H工艺生产超低碳钢种的可行性。为超低碳钢种生产工艺的多样性、成熟型提供新的思路。通过LF-RH生产工艺碳成分稳定控制≤0.015%,RH钢水出站钢渣w(Fe+MnO)≤2%等关键指标稳定可控。     

轴承钢LF精炼深脱硫工艺的研究

为进一步降低轴承钢的硫含量,从脱硫热力学和动力学两方面着手,通过现场试验数据分析,对影响脱硫的炉渣成分、碱度、硫容量和w(Ca)/w(Al)等主要因素进行讨论,提出了LF精炼工艺优化措施。结合工业优化试验,结果表明:控制精炼渣w(SiO_2)≤5%,R≥10,w(FeO+MnO)≤0.5%,w(CaO)/w(Al_2O_3)=1.6~1.7时,轴承钢精炼脱硫率能达到94%,w(S)≤20×10~(-6)。     

湘钢提高特厚钢板内部质量生产实践

通过优化LF渣系,VD和LF的吹氩制度以及连铸的工艺参数,有效地提高了钢水的洁净度和板坯质量,优化后钢水中w(P)≤0.015%、w(S)≤0.003%、w(O)≤4×10-6、w(H)≤1.3×10-6、w(N)≤40×10-6。板坯的中心偏析和疏松均为C类1.0级,钢板中心偏析和疏松均为C类0.5级;钢板平均探伤合格率提高了3.15%,探伤合格率最高达到了99.51%。     

超低碳超低硫钢控硫工艺研究

介绍了首钢股份公司迁安钢铁公司在冶炼超低碳超低硫钢过程中工艺、操作等方面的经验,并试验对比低硫钢和超低硫钢对硫含量的控制,得出了硫含量的控制工艺路线,成品w(S)≤0.003 5%的过程能力指数由0.85提高至1.13。通过铁水预处理、转炉主副原料控制、生产计划优化、出钢渣洗、RH脱硫等措施可将低硫钢种90%板坯成品w(S)控制在0.003%以内,与低硫钢种RH工序前均采取相同工艺的前提下,不同的是在RH合金化后,加入脱硫剂将钢液w(S)从0.002 6%降低至0.001 4%,最终超低硫钢成品w(S)全部控制在0.002%以内。     

夹杂物对20Mn23AlV钢中厚板边部开裂缺陷的影响

采用连铸工艺生产的20Mn23AlV钢铸坯(w(C)=0.04%～0.12%,w(Si)≤0.50%,w(Mn)=21.50%～25.00%,w(P)≤0.030%,w(S)≤0.030%,w(Al)=1.50%～2.50%,w(V)=0.04%～0.10%),在热轧过程中容易出现边部开裂缺陷,严重影响了正常生产。通过对铸坯缺陷部位进行化学成分分析和扫描电镜分析,认定中厚板边部开裂的主要原因是:在第三脆性温度区间,氮化铝在奥氏体晶界析出,降低奥氏体晶界的结合能,进而降低了钢的塑性;钢中锰含量高,凝固过程中柱状晶组织发达,易形成穿晶组织、裂纹等缺陷;在连铸生产过程发生卷渣,卷入铸坯的夹杂物与基体的延展性不同,随着轧制的进行而产生裂纹。对炼钢及连铸过程工艺参数进行了优化,降低了钢中氮化铝夹杂数量,减少了保护渣卷入钢水中的频次,中厚板边部开裂率由28%降低至3%以下。     

大功率风电主轴承用GCr15SiMn2轴承钢Φ800 mm锻材试制

大冶特钢通过70 t电弧炉→LF→RH精炼→20 t模铸钢锭→锻造的工艺试制出直径Φ800 mm高碳铬轴承钢GCr15SiMn2大规格锻材,产品用于制作5 MW及以上大功率风电机组主轴承。采用控制钢中残余元素w[Ti]≤0.001 6%、高碱度渣精炼[CaO(48%～55%)-SiO₂(3%～8%)-Al₂O₃(30%～40%)-MgO(4%～6%),碱度R≥6]、RH真空处理、保护浇注、合理的浇注工艺(浇注温度和速度)及两镦两拔锻造(综合锻造比≥4)等措施,钢材的低倍组织级别1.0级,钢中B细、D细、DS类夹杂物均不大于1.0级,碳化物带状级别CZ7.5级,钢的淬透性J45 mm达到61.0HRC,各项性能均满足标准要求。     

构筑成形工艺用高品质SA508-3钢连铸坯试制

为满足构筑成形工艺用高品质SA508-3钢连铸坯开发需要,本研究突破了连铸板坯低硫、低磷与低氧纯净度控制的技术难点,通过长流程冶炼工艺,结合低拉速、低过热度以及铸坯凝固末端压下技术,实现了高纯净、高致密、高均质的250 mm厚SA508-3钢连铸坯技术开发。经低倍、化学成分及夹杂物检测分析,铸坯中只存在较轻的缩孔、疏松缺陷;钢中杂质元素：w(P)≤0.006%,w(S)≤0.0015%,w(T.O)≤0.0015%,w(H)≤0.0002%,碳含量波动≤0.03%;A,B,C,D和Ds五类夹杂物均≤1.0级,满足高品质核电锻件构筑成型用SA508-3钢的技术要求。     

超纯轴承钢的精炼工艺

通过控制电炉(供氧强度、渣中氧化铁比例、出钢挡渣率、出钢钢液的氧活度)、钢包炉(精炼渣系、脱氧剂、钢液温度、精炼时间、底吹氩压力、精炼钢包耐火材料的选择、铁合金种类的选择)、真空脱气(真空度、真空时间、底吹氩压力)的工艺参数以及真空后的软吹氩搅拌、并采用IPAS系统和控制钢液浇铸速度,使超纯轴承钢(SFGCr15)的w(S)、w(Ti)、w(O)分别达到0.003%、0.001 2%和0.000 7%以下,钢中非金属夹杂物也处于较好水平,满足了国际顶尖轴承厂家对轴承钢的超纯要求.     

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.