45钢矩形连铸坯中心裂纹的分析和控制

统计分析了[P]、[S]、[Mn]/[S]和钢水过热度等工艺因素对钢厂45钢(0.44%-0.50%)160 mm×200 mm矩形坯中心裂纹的影响.根据分析结果,采用控制[P]≤0.020%、[S]≤0.015%、[Mn]/[S]≥40,钢水过热度≤25℃,拉速1.8 m/min时优化二冷水量等工艺措施,使中心裂纹发生率由原来的82.76%降低到22.41%,1级以上中心裂纹发生率由原来的22.41%降低到0.51%.     

LD-氯站流程生产Q235B钢连铸板坯中间裂纹的分析与控制

针对LD-氩站流程生产Q235B钢230 mm连铸板坯出现的中间裂纹,利用光学显微镜、扫描电镜和能谱仪对中间裂纹宏观和微观特征进行了系统分析。结果表明,判断扇形段接弧不良、辊缝精度差、辊子错位等是中间裂纹形成的外因;裂纹带上有粗大的晶粒,且有明显的Mn、S等元素以及复合夹杂物形态聚集是铸坯产生中间裂纹的内因。通过控制接弧精度≤±0.3mm、辊缝精度≤±0.5 mm、二冷比水量0.50 L/kg、成品[S]≤0.030%、[Mn]/[S]≥15等工艺措施,减少甚至杜绝板坯中间裂纹的发生,提高了连铸板坯的心部质量。     

连铸小方坯变形和角裂漏钢的研究

通过对唐钢第一炼钢厂仿罗可普连铸机生产的连铸小方坯的现场调查、测试和统计，分析了连铸小方坯变形和角裂漏钢的特点及规律，系统研究了钢液成分S含量和[Mn]/[S]、C含量、P含量，连铸工艺参数浇注温度、结晶器冷却、二次冷却水量、冷却均匀性和设备状况结晶器倒锥度、结晶器振动偏摆、引锭杆不对中等因素对连铸小方坯的变形和角裂漏钢的影响。指出钢液[Mn]/[S]过低是导致小方坯变形和角裂漏钢的主要内在因素，而浇注温度高、二次冷却不均是其外在影响因素，并分析了小方坯的主要变形(菱变、塌肩)的形成机理，认为角裂是由偏离角纵裂和对角线裂纹复合而成的。     

涟钢常规板坯纵裂纹产生原因及控制措施

本文根据涟钢板坯连铸机的生产实践,对铸坯表面纵裂纹的特征和形成过程进行深入研究,重点分析和总结结晶器及其冷却、钢中[Mn]/[S]值、保护渣性能、设备状态等对表面纵裂纹的影响,并提出相应的控制措施。     

板坯中间裂纹产生原因及防止措施

针对天铁热轧1#板坯连铸机生产的板坯中间裂纹严重的问题,通过低倍检验分析形成板坯中间裂纹的影响因素。结果表明:拉坯速度、Mn/S比、设备辊缝精度与铸坯中间裂纹密切相关,其中设备精度是影响铸坯中间裂纹的主要因素;将拉速控制在0.85m/min,可以防止Q235B钢铸坯中间裂纹产生;当钢中Mn/S>90,普碳钢铸坯无中间裂纹产生;将辊缝偏差调整至0.3mm以下,可有效防止铸坯中间裂纹的产生。     

宝钢厚板边裂成因分析和改善

边裂是影响宝钢厚板质量的一个重要因素.对厚板边部的非连续弧形裂纹缺陷取样,进行金相分析,并对连铸板坯进行对比轧制试验,证实钢板边裂是由连铸板坯角部横向裂纹引起.分析了影响板坯角部横裂的结晶器保护渣、二冷水、结晶器、浇注速度等工艺因素.在此基础上,提出了改善板坯角部横裂的有效措施,即改进保护渣性能、优化二冷水水量分配、弱化结晶器冷却、稳定结晶器锥度和采用合适的浇注速度等等.实施以上措施后,钢板边部裂纹大幅度减少.     

连铸板坯网状裂纹成因及影响因素的研究

采用金相显微镜、SEM、TEM和EDS等方法,分析了因连铸板坯表面冷却不均匀引起γ→α反复相变导致碳氮化物在晶界析出,并在外力(热应力、弯曲矫直应力等)作用下产生沿晶界开裂的网状裂纹的形成机理,以及钢中[C]、Mn/S、[Al]、[V]、连铸冷却强度等对连铸板坯网状裂纹的形成和扩展的影响.     

LF-VD过程控制硫化物夹杂级别的研究

从LF/VD的脱氧工艺、钢中的[Mn]/[S]、Als含量以及搅拌状况等方面对硫化物夹杂级别的控制作了试验研究,其结果表明,Ca合金脱氧对其影响重大;[Mn]/[S]＞160时可以使硫化物夹杂的评级控制在1级以下;即使在低Als状态下,硫化物夹杂物以Ⅱ类形式析出;且搅拌的作用具有多重性.     

连铸小方坯变形和角裂漏钢的研究(续)

通过对唐钢第一炼钢厂仿罗可普连铸机生产的连铸小方坯的现场调查、测试和统计，分析了连铸小方坯变形和角裂漏钢的特点及规律，系统研究了钢液成分S含量和[Mn]，[S]、C含量、P含量，连铸工艺参散浇注温度、结晶器冷却、二次冷却水量、冷却均匀性和设备状况结晶器倒锥度、结晶器振动偏摆、引锭杆不对中等因素对连铸小方坯的变形和角裂漏钢的影响。指出钢液[Mn]／[S]过低是导致小方坯变形和角裂漏钢的主要内在因素，而浇注温度高、二次冷却不均是其外在影响因素，并分析了小方坯的主要变形(菱变、塌肩)的形成机理，认为角裂是由偏离角纵裂和对角线裂纹复合而成的。     

SS400钢板坯三角区裂纹和中心裂纹成因及预防

对济钢一炼钢３＃板坯铸机生产ＳＳ４００钢,铸坯产生三角区裂纹和中心裂纹的原因进行了分析,并介绍了在铸机精度、浇注工艺和钢水条件等方面所采取的控制措施,有效地解决了这两种裂纹的出现的问题。     

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.