浅析转炉终点控制对夹杂物的影响

针对高碳钢SWRH72A的生产,在精炼工艺相同的情况下,不同的转炉终点控制方法 ,钢水中的夹杂物种类和大小有所不同。在转炉终点碳含量控制低的情况下,对于脆性夹杂物,如钛夹杂和铝夹杂,其数量和大小都有所减少。     

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。     

基于非铝脱氧工艺的GCr15轴承钢中Ds类夹杂物控制

当前在轴承钢中氧含量已经能够控制在极低水平的情况下,Ds类夹杂物成为影响其质量稳定性的主要因素之一。为解决这一问题,本研究提出了利用非铝脱氧工艺,不使用铝作为脱氧剂,而采用硅锰预脱氧、渣面扩散脱氧、真空终脱氧、精炼过程造低碱度渣的方式生产GCr15轴承钢。与传统铝脱氧生产工艺相对比,非铝脱氧工艺轴承钢中主要夹杂物为硅酸盐,含有少量钙铝硅复合夹杂物,减少了形成Ds类夹杂物的镁铝尖晶石和钙铝酸盐,显著降低了Ds类夹杂物的含量,在轧材中能够将Ds类夹杂物稳定控制在0.5级以下,评级为0级的样品占比高达91.67%。该工艺能够获得稳定的生产效果和产品质量,并为高品质轴承钢生产提供理论及技术指导。     

Inclusion control of oil drilling steel SAE4137

针对转炉流程生产石油钻井钢SAFAl37的夹杂物控制的技术难点,采用Factsage软件研究了钢水脱氧工艺、钢包渣组成控制以及钙处理工艺。工业试验结果表明,试验钢脱氧工艺合理,脱氧后钢水氧活度均控制在5．0×10-6以下,平均3．2×10-6。试验圆钢的夹杂物数量少,夹杂物完全球化,钙处理效果较好;精炼过程夹杂物转变良好,钢包渣对夹杂物的吸附能力较强,夹杂物评级各项夹杂均低于1．5N。试制的SAFAl37圆钢力学性能满足要求,夹杂物控制工艺对钢材力学性能没有影响。     

莱钢低碳铝镇静钢冶炼生产实践

针对目前低碳铝镇静钢的质量要求,莱钢根据各工艺控制的难点,通过优化转炉脱氧工艺,采用动态脱氧机制,实现脱氧前移,有效去除钢水夹杂物;自主研发了转炉顶渣快速调整技术,为精炼快速成渣打好基础;优化精炼工艺,实现高效低成本冶炼技术,有效缩短了精炼时间,进一步降低了生产成本。     

SWRH82B硬线钢CaO- Al2O3- SiO2系夹杂物塑性化控制的生产实践

为了研究SWRH82B硬线钢通过控制精炼渣的组成实现夹杂物塑性化的可行性,通过对炼钢过程中各工序的精炼渣和钢液进行取样,并对精炼渣成分、钢液总氧含量以及夹杂物的形貌、尺寸、成分等进行检测分析。结果表明,采用无铝化脱氧,并将精炼渣的碱度控制在0.8~1.2,Al2O3质量分数控制在10%以下时,能使CaO- Al2O3- SiO2系夹杂物成为塑性夹杂物;钢水经过RH真空精炼后夹杂物尺寸变大,并且夹杂物的Al2O3质量分数降低,SiO2质量分数升高,通过相关检测分析了造成此现象的原因,并提出了改进措施。     

38CrMoAl钢精炼过程夹杂物生成及演变规律

国内某厂冶炼38CrMoAl高铝钢时由于钢中非金属夹杂物超标而导致的钢材质量不达标情况时有发生。该钢的工业试验采用了“转炉(LD)-LF精炼(铝脱氧及合金化、高碱度渣精炼)-RH真空精炼-软吹-连铸”工艺流程。为了更好地去除钢中非金属夹杂物,采用分级分段的取样方法对工业试验进行取样,从而对钢中非金属夹杂物生成原因以及演变规律进行研究。结果表明,采用高碱度渣精炼可以有效降低夹杂物中Al₂O₃的质量分数,使之改性为钙镁铝酸盐夹杂物;RH软吹时夹杂物平均成分落在液相线内。     

低飞溅气保焊丝钢ER70S-6夹杂物的塑性化控制

针对气保焊丝钢ER70S-6中大颗粒不变形夹杂易在拉拔过程引起断丝的问题,通过FactSage软件对其夹杂物的塑性化控制进行了热力学分析以及工业试验。计算结果表明,非铝脱氧的低飞溅气保焊丝钢中夹杂物熔点随Al_2O_3含量的增加先降低后升高,随MgO含量的增加呈上升趋势;钢液中Ca、Mg、Al的含量随着精炼渣碱度的升高而升高。实际生产过程中,随着精炼渣碱度提高,夹杂物中Al_2O_3和MgO含量有所上升,夹杂物的变形能力降低。     

高速重轨钢的脱氧与夹杂物控制

以U75V高速重轨为例,对冶炼过程的全氧含量和夹杂物的形貌、尺寸及成分进行了系统分析,对重轨钢精炼过程的脱氧与夹杂物控制进行了探讨.结果表明,炉渣碱度高有利于Si的脱氧,LF精炼后可将钢中全氧质量分数降至15×10-6以下,但高碱度会导致钢中脆性夹杂物增多;高真空虽然对碳脱氧有利,但易引起钢中铝含量升高,不利于夹杂物的...     

山钢集团莱芜分公司45tLF炉渣系工艺研究

针对山钢集团莱芜分公司窄带钢生产中夹杂物超标控制不稳定,造成客户在使用过程中出现弯裂、重皮等质量缺陷,通过优化LF炉精炼渣系,优化造泡沫渣工艺条件,提高了精炼渣对夹杂物的捕捉能力及顶渣埋弧效果,促进了夹杂物的去除及快速脱氧、脱硫,提高了钢水洁净度,降低了夹杂物含量,满足了客户需求.     

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.