钨合金白口铸铁共晶碳化物团球化的研究

针对钨合金白口铸铁脆性大,应用于承受冲击载荷的工况下安全性差,使用范围受到严格限制,探讨了碱金属元素钾、钠对钨合金白口铸铁组织和性能的影响。结果表明:钨合金白口铸铁经钾、钠处理后,共晶碳化物由网状分布变为团块状甚至团球状分布,碳化物明显细化,分布均匀性增大,分析了共晶碳化物团球化的机理。碳化物形态的改善,导致钨合金白口铸铁的冲击韧性和抗冲击磨损能力明显提高。     

钨合金白口铸铁衬板的研究和应用

研究了用钾、钠变质处理钨合金白口铸铁时对其组织和性能的影响。结果表明，变质处理后，共晶碳化物由网状分布变成断网状、团球状分布。碳化物明显细化和分布均匀化，碳化物形态的改善，致使该铸铁的冲击韧性和抗冲击磨损性能明显提高，其衬板应用于球磨机研磨矿粉，使用安全，可靠，寿命达到高锰钢衬板的3倍以上。     

低合金白口铸铁的稀土变质机理及新工艺

本研究首先实验肯定了抗磨低合金白口铸铁可以通过稀土变质处理使M₃C型碳化物成为板块状及断开分布,从而明显地提高了它们的韧性及抗磨性。
稀土变质剂在白口铸铁结晶过程中的作用经试验确认为:(1)形成硫氧化物有利于初生奥氏体在熔体中各处形核,及在固液界面富集造成成份过冷区使奥氏体枝晶轴次发达。两昔均有利于将共晶碳化物隔断;(2)促使共晶转变温度降低,则有利于离异共晶的增长,而扩大共晶转变温度范围;则有利于共晶结晶的体积形核;最后稀土在增长的共晶碳化物上选择吸附则对获得板块状碳化物有利。
以上述的稀土变质机理假说为依据,试验开发了采用综合孕育剂及综合变质剂的两步变质处理的新工艺,在采用较少的稀土变质剂用量时,仍可获得较高韧性的白口铸铁。     

等温球化处理过程中热变形白口铸铁中碳化物的ostwald长大现象

对亚共晶白口铸铁经高温形变后所获得的碳化物在等温球化过程中球化长大进行了研究。结果表明：碳化物是以大粒子吞食小粒子和短棒状碳化物溶断及律端溶解自身球化的方式球化长大的，其特征是碳化物尺寸逐渐增大，数目逐渐减少，碳化物长大速度符合经验公式V＝1．172×10-3／（0．326＋0．0064t）2，而其含量保持不变，长大规律符合ostwald熟化规律。     

稀土变质钒白口铸铁中碳化物球化机理

探索了用变质方法改善钒白口铸铁中碳化物的形貌和分布。用稀土综合变质剂对钒白口铸铁进行了变质处理,使钒白口铁中方块状先共晶碳化物和条状共晶碳化物变为圆整时球状碳化物,韧性和机械性能明显提高。
研究表明,一定的钒量是碳化物获得球化的必要条件。变质过程中产生的大量的高熔点的硫化物、氮化物是VC非均质形核的基体,对VC以离异共晶方式生长起着重要作用。稀土的脱硫脱氧作用,提高了VC—熔体间的界面能,降低了VC的表面能的各向异性,使VC各个生长锥以在致相等的速度增长,从而长成球形。同时,高的界面能有利于在生长过程中球面的稳定性。
稀土综合变质剂正是综合了提供非均质形核基体与提高VC—熔体界面能、降低界面能各向异性的优点,而且前者与后者之间互相促进,因而发挥了较强的球化作用。     

低合金白口铸铁的稀土铝氮综合变质机理

通过稀土铝氮综合变质处理使低合金白口铁中碳化物成为团块状,并使韧性显著提高。根据稀土、铝和氮三种变质元素分别及一同加入铁水后浇注成试样的物理冶金检测结果,讨论了各变质元素在熔体中的物化行为及这些行为对白口铸铁凝固的影响,尤其对碳化物结晶的影响。     

钨系抗磨白口铸铁的研究

研究了钨对低合金白口铸铁显微组织、机械性能和抗磨性的影响。研究结果表明:钨含量在3.5～8.0％的铸铁经适当热处理可形成点状石墨析出;钨含量增加,碳化物的显微硬度增加,抗拉强度和冲击韧性提高;钨系抗磨铸铁具有优良的耐磨性能,达到甚至超过了马氏体高铬白口铸铁。     

稀土对余热淬火低合金耐磨蠕铁组织和性能的影响

研究了稀土对余热淬火低合金耐磨蠕铁中石墨形态及碳化物尺寸的影响。试验表明，稀土能使低合金铸铁组织中的板条状碳化物细化，其原因主要和细小均匀分布在基体中的蠕墨对碳化物长大起阻碍作用有关。生产实践表明，这种稀土变质低合金铸铁在余热淬火处理条件下能获得较好的韧性及耐磨性。     

高铬白口铸铁的结构研究

用扫描电镜、X—射线衍射分析仪及光学显微镜对5种亚共晶成份高铬白口铸铁的铸态结构进行了研究。结果表明,高铬白口铸铁中的碳化物组成及形态依赖于Cr/C值而变化,晶界处存在Cr,Si元素偏析。     

脉冲电流参数对过共晶高铬铸铁近液相线熔化后凝固组织的影响

对过共晶高铬铸铁近液相线溶化后的凝固过程进行脉冲电流处理,研究了脉冲电流参数（脉冲电压和频率）对凝固组织的影响.发现脉冲频率和电压的增大都有助于过共晶高铬铸铁凝固组织中碳化物的细化和粒化.脉冲频率的增大促进大量细小颗粒状初生碳化物的析出,离异共晶现象变得更加明显,层片状共晶碳化物减少.脉冲电压的增加促进初生碳化物细化和粒化,片状共晶碳化物变短.过高的电压也促进离异共晶,导致更多的初生碳化物的形成.     

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.