工程车转向臂下端轴断裂原因分析

采用扫描电镜测试、金相检验、硬度测试、化学成分分析等方法对某型号重载工程车转向臂下端轴的断裂原因进行了分析。结果表明:该轴的断裂属于疲劳断裂,轴肩过渡处圆角未达到设计要求以及机加工刀痕、冶金缺陷引起该位置应力集中是导致其疲劳断裂的主要原因。     

堆取料机走行减速机故障原因分析

对斗轮堆取料机走行减速箱齿轮齿面断裂口及齿面磨损处进行宏微观分析。认为：该齿轮系是在应力集中条件产生早期疲劳断裂。造成齿轮疲劳断裂的原因主要是,热处理工艺过程中齿轮渗碳不完善,造成齿轮表面脱碳,致使材料力学性能未达到设计要求,齿轮的疲劳抗力降低,加之圆角加工较差,工作时产生应力集中,加速了齿轮的疲劳断裂。     

线材粗轧减速机齿轮轴断裂失效分析

粗轧减速机高速轴齿轮在使用中断裂,通过对制作工艺、轧制能力、显微组织、化学成分、齿轮设计参数等方面的分析,结论是疲劳断裂,齿轮热处理质量差及设计参数不合理是产生疲劳断裂的原因.     

基于动载荷谱的齿轮弯曲疲劳寿命预测

为了探讨齿轮弯曲疲劳寿命计算问题,将齿轮疲劳总寿命分为两个阶段,即疲劳裂纹萌生寿命和裂纹扩展寿命.通过ADAMS软件仿真实验齿轮的工作情况,使其接近真实状况,得到齿轮载荷谱.根据齿轮载荷谱,利用有限元ANSYS软件分析在齿轮齿根危险截面处的最大应力.采用断裂力学、雨流法和Miner疲劳损伤累积模型,对考虑动载荷情况下的齿轮弯曲疲劳寿命进行预测,推导了齿根裂纹萌生期和扩展期的疲劳寿命计算公式.在高频疲劳试验机上对算例齿轮进行了双齿脉动加载齿根弯曲疲劳寿命实验研究,理论计算结果与实验结果基本吻合,验证了本文理论分析的正确性.      

内燃机车车轴断裂原因分析

通过对断口花样的综合分析，查明了内燃机车车轴断裂的原因，于由轴与轴套接触不当而产生相对运动，致使匹配两表面微振磨损，形成划痕和磨损坑并发展成大量微裂纹，而随后在循环载荷作用下，由微振磨损产生的裂纹处开始发生疲劳裂纹扩展，并导致了最终疲劳断裂。     

线材精轧机螺旋伞齿轮失效分析

分析了２０ＣｒＭｎＴｉ钢渗碳螺旋伞齿轮在线材精轧机服径过程中早期失效的原因。分析结果表明，齿轮材料正常，其疲劳断齿是齿根未硬化，强度不足和齿根部刀具切痕生产应力信中共同作用的结果。     

引风机轴断裂失效分析

该引风机轴断裂性质是疲劳断裂，造成断裂的主要原因是不恰当的补焊工艺。补焊时形成的裂纹是疲劳断裂的纹源。基体钢材晶粒粗大也是造成该轴早期断裂的原因。     

空气透平压缩机齿轮裂纹原因分析

对空气透平压缩机齿轮裂纹进行了分析，结果表明，裂纹起源于齿根表面脆性氧化物夹杂处。由于该处应力较集中，加之材质强度偏低导致疲劳强度亦偏低，裂纹由此萌生并逐渐扩展成疲劳裂纹。     

酸洗拉矫机减速机弧形锥齿轮失效分析及改进技术

介绍了宝钢四冷轧酸轧拉矫机弧形锥齿轮齿根疲劳断裂、齿面剥落、齿尖压溃等失效情况,在对失效齿断裂面宏观形貌、齿轮弯曲、接触强度校核、化学成分、齿轮热处理硬度、金相组织、啮合情况等做详细分析的基础上,确定弧形锥齿轮失效的主要原因,并采取提高弧形锥齿轮弯曲和接触强度安全系数、齿轮材料改善、齿轮加工齿面修形、拉矫机运行负载限制等措施,对弧形锥齿轮进行改进设计.     

基于具有动态特性的小波变换的齿轮轮齿表面故障诊断

利用小波变换方法来处理轮齿表面故障的诊断问题。在疲劳试验中，测量来自齿轮传动箱及齿根应力的振动加速度以及观察轮齿表面。随着疲劳试验的进展，齿轮的轮齿表面由于剥落损伤而受损。当一个轮齿失效时，使用振动分析，可以诊断出失效的轮齿。然而，由于邻近的多数失效轮齿的原因，诊断出每一个失效的轮齿是困难的。使用齿根应力的时间-频率分析能够可以发现轮齿表面的失效位置。     

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.