纯铁电渣重熔的碳、硫控制

本文深入研究了超低碳超低硫纯铁产品YT01B电渣重熔冶炼工艺,查明了钢锭增碳和影响脱硫效果的主要原因。通过采用三元提纯渣系、改进提纯渣质量、控制提纯渣在冶炼过程中的氧化性变化等措施,解决了钢锭下部增碳和脱硫差的问题,使电渣冶炼纯铁增碳量在0．0011％以下,平均脱硫率达到62％,成品碳、硫含量均〈0．003％。     

低碳低硅钢精炼渣脱硫的实验室研究

本文通过实验室研究,开发了LF炉脱硫精炼用低碳低硅精炼渣系.通过半球法熔点测试试验,确定渣系的合理成分配比,低碳低硅渣系的成分是高温氧化铝微粉(40%)、石灰(50%)、萤石(2%)、碳酸钡(8%).通过实验室低碳低硅精炼渣系脱硫试验得出,自配渣系与工厂里使用的AD粉渣系相比,两者的脱硫效果相当,均为79%左右.但自配渣系在增碳增硅方面,与工厂使用的AD粉渣系相比,增碳增硅量较少,使得自配渣系优于工厂使用的AD粉渣系,自配渣系基本达到低碳低硅钢的精炼要求.     

电渣重熔高温合金渣系对冶金质量的影响

 电渣重熔渣系的组成直接关系到高温合金的冶炼质量和表面质量。分析了高温合金电渣重熔渣系选择的基本要求和组成特点,确定了高温合金电渣重熔常用渣系的基本类型。通过研究高温合金电渣重熔渣系对冶金质量的影响可知：高碱度渣系具有较好的脱硫效果;为了降低渣料中的不稳定氧化物,应在使用前对萤石进行提纯;可以采用改变渣系组元和加入铝粉的方法,从而减少铝、钛等易氧化元素的烧损;选择低熔点渣系,可有效减少和避免含钛高温合金在电渣重熔过程中易出现的锭身表面渣沟、腰带缺陷、锭身分流眼等表面缺陷。提出的高钛低铝型高温合金电渣重熔渣系配比（质量分数）为：CaF2 65%～70%、[Al2O3]12%～15%、[CaO]12%～15%、[MgO]3%～8%、[TiO2]2%～5%。高铝低钛型高温合金电渣重熔渣系配比（质量分数）为：[CaF2]60%～65%、[A12O3]15%～20%、[CaO]15%～20%、[MgO]0～5%、[TiO2]0%～2%。     

碳质引弧剂代替钛质导电渣引弧生产G20CrNi2MoA电渣钢

因标准要求G20CrNi2MoA渗碳轴承钢电渣锭中的Ti含量≤0．005％，在母材[Ti]为0．005％-0．009％时，原使用钛质导电渣引弧，2．5t电渣锭中可含量为0．003％-0．011％部分高于0．005％，但改用碳质引弧剂(碳70％，萤石30％)引燃生产的重熔锭中的Ti含量降至0．002％-0．005％，达到标准规定残余n含量的要求。已用碳质引弧剂生产碳素钢、合金结构钢、轴承钢、合金工具钢、不锈钢和高温合金53000t电渣锭，其成本较使用导电渣低。     

电渣重熔过程电源频率对电渣锭洁净度的影响

电渣重熔采用低频供电可以提高功率因数、降低电耗,并实现电力系统的三相平衡。然而,其对电渣锭冶金质量特别是洁净度的影响还缺乏足够的数据支撑。为了研究电源频率特别是低频操作对电渣重熔锭洁净度的影响,采用实验室小型低频电渣重熔炉,以304奥氏体不锈钢、GCr15轴承钢为研究对象,详细分析了不同的电源频率对电渣锭化学成分、气体含量、夹杂物分布的影响规律。研究结果发现,与工频电渣重熔相比,不论是不锈钢还是轴承钢,当采用低频电源(2、1、0.4、0.1 Hz)电渣重熔后(在其他工艺参数如渣系、渣量、电流、电压、气氛等完全相同的情况下),电渣锭中的氧质量分数(0.010%～0.013%)大幅增加,对氮含量影响很小。电渣锭中的铝含量明显增加,而其他化学成分变化很小。与此相对应,低频电渣重熔锭的夹杂物数量也明显增加,且增加的夹杂物主要以氧化铝为主,但是夹杂物主要以小于10μm的细小夹杂为主,大颗粒夹杂物略有增加,但是数量较少。氧含量增加的主要原因是低频电源的直流倾向增大,使重熔渣池中的氧化铝发生了电解(30%Al₂O₃+70%CaF₂渣系...     

氩气保护对电渣重熔气阀钢NCF3015铝钛烧损的影响

气阀钢NCF3015 Φ280 mm×1700 mm电极（/%:0.03～0.08C,13.5～15.5Cr,30～33.5Ni,1.7～2.1Al,2.4～2.9Ti,0.65～0.80Mo,0.65～0.80Nb,0.002～0.006B）经全同轴式惰性气体保护电渣重熔成Φ340 mm0.80 t电渣锭。在使用三元预熔渣70CaF₂-15Al₂O₃-15CaO以熔速为4 kg/min的全氩气保护条件下,试验了气阀钢NCF3015电渣过程中Al、Ti烧损的烧损量及Si的变化情况和脱S率,并阐述了机理。结果表明,Al相对Ti是主要的烧损元素,Al的平均烧损量为-0.071%,Ti的平均烧损量为-0.035%。从底部至顶部Al,Ti的烧损都逐渐减小,与常规电渣重熔烧损率相比,氩气保护对减小Al,Ti的烧损作用显著。Al、Ti的烧损导致重熔初期Si含量略增。该渣系有一定的脱硫效果,平均脱S率36.7%。     

012Al模具钢电渣重熔工艺的优化

在1t锭型的012Al模具钢电渣重熔工艺优化试验中，在保证重熔锭质量的前提下，通过重熔过程均匀加入铝粉等工艺措施。采用55?F2-30%Al2O3-5?O-5%MgO四元渣系，当填充比为0.48时，电耗较0.2填充比降低43.5%。且比70?F2-30%Al2O3的元渣系0.48填充比的电耗降低29%。     

改善34CrNiMo6含硫电渣钢B类夹杂物的工艺实践

34CrNiMo6钢(/%:0.30~0.38C,0.50~0.80Mn,≤0.40Si,0.015~0.035S,≤0.035P,1.30~1.70Ni,1.30~1.70Cr,0.15~0.30Mo)的冶金流程为30 t EAF-LF-VD-浇铸Φ470 mm电极-3.6 t ESR锭(Φ610 mm)-锻成Φ280 mm棒材。在分析冶炼过程中影响钢中B类夹杂物级别因素的基础上,通过将电极氧含量从20×10~(-6)降至11×10~(-6)、同时电极S含量由0.035%提高到0.045%,进而减少重熔过程FeS等附加剂的添加量,将萤石-Al_2O_3-SiO_2-MgO重熔渣系中萤石由45%提高到60%及SiO_2由15%降低到5%等措施,生产钢材的B类夹杂物级别由原先的2.5级降至≤1.5级,并且钢中硫分布均匀适中,保证了电渣钢的质量。     

核电用超纯奥氏体不锈钢316H电渣重熔氢含量控制

为研究电渣重熔过程氢含量控制影响因素，电渣重熔生产Φ590 mm电渣锭时试验了4种不同组成的电渣渣系，同时电渣重熔过程配合氩气保护。通过试验不同渣系组成及不同氩气流量下保护气氛，最终确定电渣重熔在w(CaF₂)∶w(Al₂O₃)∶w(CaO)=60%∶30%∶10%组成渣系下，采用40 L/min的氩气流量控制，可使Φ590 mm电渣锭成品氢含量控制在5×10^-4%以下。     

316L超低碳奥氏体不锈钢超细丝原料生产实践

采用1 t 3相有衬电渣炉-底吹氩精炼-铸φ90 mm棒-100 kg电渣重熔工艺流程成功地生产出满足生产φ0.018 mm超细丝洁净度要求的316L不锈钢原料（/%:≤0.03C、≤1.0Si、≤2.0Mn、≤0.035P、≤0.030S、16～18 Cr、12～15Ni、2～3Mo）。通过渣料为（/%）25CaF₂-25Al₂O₃-50CaO,3根纯铁自耗电极的熔炼过程逐步加铬铁、镍板和硅铁,获得要求的成分,并用AlSiMn合金和SiCa粉脱氧,底吹氩气搅拌,直接浇铸成φ90 mm铸棒,再经φ160mm电渣重熔炉精炼成100 kg锭。结果表明,电渣锭中总氧含量为（15～20）×10^-6,平均夹杂物含量为16.2个/mm²,95%夹杂物尺寸小于5μm,没有发现大于10μm的夹杂物,可满足生产超细不锈钢丝的要求。     

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.