简化退火高强度冷镦钢SCM435盘条的研制

马钢采用铁水预处理-50t顶底复吹转炉冶炼-65tLF精炼-6流140mm×140mm方坯连铸-SMS控轧控冷高速线材轧机工艺流程,生产Φ5.0～22.0mm简化退火0.35C高强度冷镦钢SCM435盘条。通过LF精炼及连铸保护浇铸和电磁搅拌,铸坯中氧含量达18×10^-6。经控轧控冷生产的线材抗拉强度平均为746.5MPa,较常规工艺轧制的线材低200MPa。因此,控轧盘条球化退火时间较常规轧制盘条减少50%。     

控轧控冷工艺对SCM435钢盘条组织和性能的影响

试验钢SCM435（/%:0.33~0.38C,0.15~0.35Si,0.60~0.85Mn,≤0.025P,≤0.025S,0.90~1.20Cr,0.15~0.30Mo）盘条的生产流程为80t BOF-LF-280 mm×325 mm铸坯-160 mm×160 mm热轧坯-热连轧成Φ16 mm盘条。试验研究了160 mm×160 mm热轧坯由常规轧制工艺（开轧1060℃,精轧930~950℃,吐丝860~900℃,冷却速度0.5~0.6℃/s）和控轧控冷工艺（开轧1060℃,精轧820~850℃,吐丝780~820℃,冷却速度0.4~0.5℃/s）对SCM435钢热轧盘条组织和力学性能的影响。结果表明,随着精轧温度的降低和冷却速度的减小,钢热轧盘条的组织得到改善,抗拉强度明显降低;常规工艺轧制SCM435钢热轧盘条的抗拉强度平均952 MPa,组织为铁素体+珠光体+贝氏体+马氏体,控轧控冷工艺轧制的SCM435钢热轧盘条的抗拉强度平均817 MPa,组织为均匀的铁素体+珠光体。结合控轧控冷工艺原理对钢的组织和性能变化进行了分析。     

异型钢丝用65Mn热轧盘条的生产实践

经过弹簧钢产品长期的研发和生产实践,安钢形成了异型弹簧钢丝用65Mn热轧盘条稳定的转炉冶炼、LF精炼、方坯连铸及控轧控冷工艺。规格Φ6.5 mm的65Mn盘条抗拉强度为1075 MPa~1115 MPa,断面收缩率达到50%以上,且组织索氏体比例达到80%以上,能够满足用户制作异型弹簧钢丝的各项要求。借助光镜和扫描电镜对生产中出现的开裂问题进行了分析,盘条局部增碳和组织异常是导致开裂的主要原因,通过采取有效措施避免了类似质量问题的发生。     

宣钢SWRH82B盘条控冷工艺的研究

利用Gleeble热模拟试验机对宣钢SWRH82B盘条的CCT曲线进行测量绘制,采用金相法进行验证,研究了冷却速度对SWRH82B组织相变的影响。结合宣钢设备现状,确定适用于宣钢Φ12.5 mm规格的SWRH82B盘条生产的控冷工艺为相变前冷速控制为7~10℃/s为宜。     

65Mn盘条马氏体异常组织分析

针对Φ5.5 mm规格65Mn盘条在拉拔时出现脆断现象,通过显微组织观察,发现盘条断口处存在大量马氏体异常组织,采用化学成分分析、扫描电子显微镜线扫描和面扫描等方法对马氏体产生的原因进行了分析,排除化学成分异常、铸坯芯部偏析的可能,判定是因为小规格盘条在冷却过程中受冬季环境影响冷却速度过快而造成了马氏体转变。同时,经过回火试验,发现可通过高温回火改善本批65Mn异常盘条的拉拔性能。经过生产控冷试验,优化其生产工艺,冬季65Mn盘条控冷工艺调整为1～6台风机,50%风量,保温罩2～4段开,其余关闭,避免产生异常组织。     

稳定HRB500盘条通圈性能的工艺措施

介绍了唐山市德龙钢铁有限公司Φ8 mm、Φ10 mm规格HRB500盘条的产品质量状况,针对出现的问题进行了工艺优化。通过优化化学成分和微合金化物料,合理控轧控冷,依靠微合金化元素的沉淀强化和细化晶粒效果来稳定盘条线圈内的性能。工艺优化前后产品质量对比表明:优化后盘条线圈内搭接点与非搭接点力学性能指标差值明显降低,屈服强度最大差值从50 MPa降至20 MPa、抗拉强度最大差值从70 MPa降至25 MPa、伸长最大差值从4.0%降至2.0%,盘条线圈内力学性能稳定性得到有效提高。     

ML45Mn2冷镦钢盘条的研究与开发

120 t转炉-LF-VD-350 mm x430 mm铸坯-150 mm x 150 mm轧坯-轧制流程生产的ML45Mn2钢Φ16 mm和Φ18 mm盘条采用的主要工艺为:碱度1.5-2.0精炼渣,52 t中间包,电磁搅拌,轻重压下,开轧温度1 010 ~ 1 070 °C,精轧温度820 - 850°C,卷曲温度780 - 820°C,冷速0. 15 -0.4 °C/s等工艺。检验结果显示,MI45Mn2钢盘条热轧态平均抗拉强度797 MPa,平均断面收缩率50.3% ,1/4冷镦合格,金相组织为珠光体+铁素体,断面平均硬度值为92.5HRB,带状组织1.5-2.5级,满足技术要求。     

Φ5.3mm盘条高精度轧制工艺与实践

结合线材生产线设备布置情况,制订了Φ5.3mm盘条高精度轧制方案,通过严格控制轧线温度,成品孔型重新设计,精确计算减定径机组轧件尺寸与速度,在计算机控制系统采用Φ5.0mm盘条轧制程序表的基础上,开发出了椭圆度不超过0.20mm的Φ5.3mm高精度盘条,尺寸精度达到Φ5.3mm±0.1mm。     

鞍钢ER70S-G焊丝钢技术质量问题解决对策

研究了Φ5.5 mm ER70S-G焊丝钢盘条生产过程中存在的典型技术质量问题,通过优化控轧控冷工艺,解决了ER70S-G焊丝钢成品丝镀铜不均匀、成品丝焊接过程送丝稳定性差、盘条表面红锈等问题,优化后的产品满足用户生产要求.     

出口韩国Φ5.5mm拉丝用高线盘条的试制

从化学成分的控制和控冷、轧制工艺参数的制定等方面，介绍了昆钢出口韩国Φ5.5mm拉丝用高线盘条的试制情况，并对盘条冷却曲线和组织以及力学、工艺性能进行了数据分析。     

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.