EAF-LF/VD-CC工艺生产压力容器钢的洁净度研究

为了解天津钢管集团公司EAF-LF/VD-CC工艺生产压力容器钢12Cr1MoVG的洁净度水平,通过系统取样、示踪剂追踪、综合分析等方法,对LF处理前后、中间包钢水和连铸坯中总氧、显微夹杂及大型夹杂物的数量及变化情况进行了全面研究.结果表明,LF/VD精炼后钢液w(T[O])平均为15×10-6,中间包为17×10-6,铸坯为(18～24)×10-6,其中头坯＞尾坯＞连浇坯＞正常坯.铸坯中的显微夹杂物数量是3.53个/mm2,主要为球形钙铝酸盐、硅铝酸盐和铝酸盐与硫化物的复合夹杂,90%以上的夹杂物尺寸小于10μm;铸坯中大型夹杂物有铁铝硅酸盐、钙镁硅酸盐等,来源于钢的二次氧化、钢包卷渣、耐火材料侵蚀、结晶器卷渣等.     

X80管线钢洁净度研究

对X80管线钢中非金属夹杂物进行金相观察、大样电解和扫描电镜分析。结果表明:从LF进站到铸坯过程中显微夹杂物呈显著的下降趋势,降幅达77.77%,在LF和RH精炼过程中,夹杂物数量降低最为明显;铸坯中夹杂物主要类型为CaO-CaS-Al2O3复合夹杂,其xCaO/xAl2O3小于12 CaO·7Al2O3的xCaO/xAl2O3=1.71,夹杂物变性效果较差。X80管线钢从转炉终点到铸坯过程中,平均T.O呈下降趋势,LF进站到钙处理后,平均w(T.O)减少了2.06×10-6,RH精炼过程平均w(T.O)降低了2.27×10-6,需提高LF精炼操作水平和RH精炼操作稳定性。RH出站到铸坯是一个增氮的过程,增氮质量分数为2.27×10-6,保护浇铸水平较高;铸坯中大型夹杂物数量为1.46 mg/10 kg,夹杂物主要为球状的钙铝酸盐夹杂物、硅铝酸盐夹杂物以及与镁铝尖晶石形成的复合夹杂物。     

优化精炼工艺生产SPHC钢的洁净度研究

针对优化精炼工艺生产SPHC钢的洁净度进行研究,采用系统取样和综合分析,对RH精炼后、LF精炼后、中间包和铸坯钢样中T.O和N含量,显微夹杂物的变化规律以及铸坯中大型夹杂物进行了系统的分析。结果表明:采用铁水预处理(脱硫)→120t顶底复吹转炉→RH(钙处理)→连铸工艺生产的SPHC铸坯中的w(T.O)和w(N)分别为23×10-6和17×10-6,化学成分满足要求,每10kg铸坯大型夹杂物为4.76mg,与原工艺生产的铸坯洁净度基本一致,进一步优化RH精炼工艺可使SPHC铸坯具有很高的洁净度。     

IF钢中细小夹杂物的控制

 高纯净度钢的生产是21世纪钢铁企业面临的重大课题,对钢中全氧含量和夹杂物含量的控制是生产高纯净IF钢的关键技术。为此笔者提出一种全新的夹杂物控制技术——反应诱发微小异相去除钢液中细小夹杂物的工艺,设计了一种具有该种功能的复合球体,并开展了工业现场试验研究。试验结果表明：反应诱发微小异相去除细小夹杂物工艺是一种成本低、效率高、简便易行的夹杂物控制技术,它可以显著降低IF钢中非金属夹杂物数量。与传统工艺相比,采用该技术对钢液进行处理后,铸坯中氧化物夹杂的数量明显减少,尺寸变小,铸坯的平均w(［TO］)最低可达7×10-6,吨钢成本可降低5～10元。     

80 t转炉-钢包吹氩-连铸冶炼过程对Q235A钢气体夹杂含量的影响

检测和分析了80 t顶底复吹转炉-钢包吹氩-连铸流程冶炼Q235A钢(0.14%～0.22%C、0.30%～0.65%Mn)在转炉终点、转炉出钢过程合金化后、钢包吹氩、中间包、钢水和铸坯中的氧、氮和夹杂物含量.结果表明,转炉终点氧含量为350×10-6,加脱氧剂和合金化后,氧含量降低42%,经钢包吹氩,钢中氧含量进一步降低,铸坯中平均氧含量25×10-6;钢中氮含量由转炉终点20×10-6增至铸坯40×10-6;钢包加脱氧剂、合金化后吹氩,钢中可去除约50%夹杂物,使铸坯中夹杂物含量≤45×10-6,一般夹杂尺寸≤10μm,最大尺寸为20μm.     

316L不锈钢精炼过程中夹杂物成分演变

从"AOD-LF→钙处理→连铸"进行全流程取样,重点分析316L不锈钢中氧氮含量、夹杂物数密度和成分.研究发现:在冶炼过程中,钢中w(T.O)逐渐降低,钙处理后为24×10-6,较AOD还原结束时降低183×10-6,浇铸时存在二次氧化,铸坯试样中w(T.O)增加8×10-6.AOD还原期结束时,夹杂物类型主要为SiO...     

汽车用板IF钢开浇炉次板坯洁净度的分析

为系统研究某厂IF钢开浇炉次铸坯洁净度变化规律,对铸坯合理判级提供依据,采用氧氮分析、定量金相检验以及大型夹杂物检测等试验对某钢厂开浇炉次IF钢铸坯洁净度进行研究。结果表明,距引锭头部4 m处,铸坯w(T.O)=35.3×10~(-6),w(N)=48.7×10~(-6),显微夹杂物含量为8.5个/mm~2,钢水二次氧化严重,其中含示踪元素La、Ce的显微夹杂物比例分别为33%和55%,钢水受钢包渣和中间包渣影响较大。距引锭头部16 m处,w(T.O)=18.7×10~(-6),铸坯洁净度有较大的改善。随浇铸进行,洁净度好转趋势较为平缓,距引锭头部28m处,w(T.O)逐渐降低到16.3×10~(-6),铸坯洁净度与连浇第2炉、第3炉正常炉次基本一致。     

20CrMnTi齿轮钢LF精炼渣优化

针对某厂20CrMnTi齿轮钢生产过程中全氧含量控制偏高,夹杂物控制水平差等问题,研究利用FactSage热力学软件计算结果着重探讨精炼渣碱度、w(CaO)/w(Al_2O_3)、MI指数与Al_2O_3夹杂吸附能力的影响关系,最终得到适用于该厂生产齿轮钢(20CrMnTi)的LF精炼渣系范围为:w(CaO)=50%~55%,w(Al_2O_3)=22%~26%,w(SiO_2)=10%~12%,w(MgO)=5%~7%。使用该渣系进行工业试验,铸坯中全氧质量分数由17×10~(-6)降至14×10~(-6),且铸坯中显微夹杂物尺寸也明显降低,由2.0μm降至1.4μm,且工艺优化后铸坯中观察到的绝大部分夹杂物都在1 500℃液相线以内变化,夹杂物变性效果良好。     

气瓶钢中非金属夹杂物研究

针对国内某钢厂EAF-LF-VD-CC工艺生产的气瓶钢,通过全流程系统取样、综合分析的方法,对LF处理前后、VD喂线处理后、中间包钢水和连铸坯中总氧(T[O])、显微夹杂及大型夹杂物的数量及变化情况进行了全面研究,分析了夹杂物产生的原因.结果表明:经过LF和VD精炼后钢液中显微夹杂物数量由16.7个/mm2减少到6.1个/mm2,VD喂线后夹杂物变性不完全,中间包过程钢液的二次氧化严重,铸坯中T[O]能稳定在(10±2)×10-6,铸坯中大型夹杂物为0.2 mg/kg.     

X80管线钢洁净度研究

对X80管线钢中非金属夹杂物进行金相观察、大样电解和扫描电镜分析。结果表明:从LF进站到铸坯过程中显微夹杂物呈显著的下降趋势,降幅达77.77%,在LF和RH精炼过程中,夹杂物数量降低最为明显;铸坯中夹杂物主要类型为CaO-CaS-Al2O3复合夹杂,其XCaO/XAl2O3小于12CaO·7Al2O3的XCaO/XAl2O3=1.71,夹杂物变性效果较差。X80管线钢从转炉终点到铸坯过程中,平均T.O呈下降趋势,LF进站到钙处理后,平均W(T.O)减少了2.06×10-6,RH精炼过程平均W(T.O)降低了2.27×10-6,需提高LF精炼操作水平和RH精炼操作稳定性。RH出站到铸坯是一个增氮的过程,增氮质量分数为2.27×10-6,保护浇铸水平较高;铸坯中大型夹杂物数量为1.46mg/10kg,夹杂物主要为球状的钙铝酸盐夹杂物、硅铝酸盐夹杂物以及与镁铝尖晶石形成的复合夹杂物。     

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

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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.