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John Kronsbein 《金属精饰学会汇刊》2013,91(1):23-26
Several types of rectifier have been used during the last thirty-five years to supply heavy current d c for plating and allied processes. Developments have followed different, sometimes conflicting, trends in various countries. Selenium, germanium and silicon are each acclaimed best, but each design has its minor disadvantages. After studying these drawbacks, a new concept of rectifier design using silicon is now introduced, providing the utmost simplicity with reliability and long life. 相似文献
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为减少更换截齿工作量,提高掘进机截割部可靠性,开展重型掘进机截齿的失效分析及对策研究,对金相组织进行观察对力学性能进行分析.结果表明:从金相组织来看,18Cr2Ni4WA截齿碳氮共渗后,最表层碳氮化合物数量较多,耐磨性较高,基体板条马氏体和残余奥氏体韧性好;5CrNiMo钢截齿形成均匀而细小的回火托氏体,抗高温回火及抗热疲劳性能优;18Cr2Ni4WA碳氮共渗截齿比20CrMnTi截齿的抗拉强度提高9.25%,冲击韧性提高41.8%;两种截齿工业性试验寿命分别提高100%和20%. 相似文献
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通过在共晶、过共晶A1-Si合金中加入元素Bi的试验.研究了Bi元素对高硅合金的影响。Bi在A1-Si合金中形成A1-Si-Bi多元合金,具有偏晶转变的结晶特点,由于Bi的物理性能及在A1-Si合金中的不溶性、自润滑性,并以高弥散游离态分布于基体中使A1-Si合金的尺寸稳定性和耐磨性得到较大提高。 相似文献
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Gunilla Bökmark Göran Holmbom Per-Olof Persson Jan Sidén Lennart Granlund 《金属精饰学会汇刊》2013,91(3):122-130
This report presents a survey of various surface treatments to improve the wear resistance of aluminium. Over 25 different treatments have been produced and evaluated in laboratory and in application tests. Three plastically formable alloys and one pressure die casting alloy were included.The different coating systems have been characterised with respect to structure and morphology by scanning and transmission electron microscopy. The laboratory wear tests were performed by using Taber abraser and pin on disc as standard methods. As a comparison, a non-standard reciprocating adhesive wear test set-up was used. In addition, a corrosion test by accelerated outdoor exposure (SCAB) was performed. The application tests were a rotating PTFE sealed sleeve, a station chain in a food packing machine and a yarn feeder.The results from the abrasive and adhesive laboratory wear tests have been correlated to the results in the application tests. For some of the evaluated coating systems the correlation between the laboratory and the application tests is reasonably good. However, substantial difference in performance was found for other systems. 相似文献
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等温淬火球铁(ADI)优越的耐磨性 总被引:5,自引:0,他引:5
等温淬火球铁(ADI),由于其强度高,韧性好,硬度高,有优越的耐疲劳性和特有的应变强化能力,因而具有优越的耐磨性.此外ADI还具有重量轻,成本低,能源消耗低,减震性好等特点.ADI已经成功地替代了多种炭钢和低合金钢铸件,锻钢件,表面淬火和氮化处理的钢件,铜合金铸件,组装件等,已经广泛应用于工业的各个部门,取得了明显的经济效益.文中列举了其在需要减小摩擦力的滑动摩擦条件下,需要摩擦力工作又要求耐磨条件下,磨料磨损以及某些特殊磨损条件下的应用实例. 相似文献
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研究了准贝氏体钢销盘磨料磨损和冲击磨料磨损的耐磨性和磨损机制,确定了回火温度对耐磨性的影响,探讨了残余奥氏体的机械稳定性及其对耐磨性的作用。结果表明:准贝氏体钢渗碳层的耐磨性接近或优于18Cr2Ni4WA钢;以微切削型磨料磨损为主的准贝氏体钢渗碳件,宜采用180℃回火,以应变疲劳型磨料磨损为主的准贝氏体钢渗碳件,宜采用280℃回火;残余奥氏体的机械稳定性对材料的耐磨性具有重要作用。对于微切削型磨料磨损,机械稳定性高的残余奥氏体不利于提高耐磨性;对于应变疲劳型磨料磨损,机械稳定性高的残余奥氏体明显提高耐磨性。 相似文献
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基于某大型加工车间普通车床中心架支撑爪经常因磨损严重而废弃,对目前市场上的中心架支撑爪进行调查及组织观察,分析发现目前使用的支撑爪材料为球墨铸铁.将支撑爪材料改为镍硬铸铁,进行耐磨性测试,通过热加工,发现在保证工件不被磨损的前提下,采用镍硬铸铁,将极大提高支撑爪耐磨性能.将镍硬铸铁应用在支撑爪上,不但能降低因磨损更换带来的经济损失,更能保证加工工件的精密性. 相似文献
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用RF-Mg-Ti对低碳铸造高速钢(6W6Mo5C44V)模具材料进行变质处理,消除了钢中网状共晶碳化物,细化了基体组织,减轻了W、Mo元素偏析,变质处理后,高速钢硬度,红硬性和强度变化不大,但断裂韧性(K1c)和疲劳裂纹扩展门槛值(ΔKth)有所提高,冲击韧性(ak)提高1倍以上,耐磨性也明显提高,各项性能指标达到了锻造高速钢水平,用RE-Mg-Ti变质处理低碳铸造高速钢,可以实现“以铸代锻”。 相似文献
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在对浅球形零件拉伸过程中凹模入口处切向压应力以及临界起皱切向压应力分析的基础上 ,针对不同凹模结构进行了内皱校核 ,证明了凹模入口尺寸对消除内皱的重要性 ,进而给出了成形零件在不同精度要求下凹模入口尺寸的计算方法 相似文献
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针对V法铸造工艺的特殊性,分析了V法铸造涂料快干性、粘附性、致密性、透气性和涂挂性的影响因素,介绍了涂料性能的测试方法.将研制的V法铸造涂料用于高锰钢铸件,试用结果表明,涂料具有较快的干燥速度、与薄膜较好的粘附性、合理的透气性和致密性及良好的涂挂性,可满足V法铸造耐磨铸件的工艺要求,有效提高耐磨铸件的质量. 相似文献
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超高锰钢耐磨性及其冲击磨料磨损行为的研究 总被引:1,自引:0,他引:1
通过动载荷冲击磨料磨损试验及磨损后磨面硬度测量,利用SEM和TEM观察磨损表面形貌和磨损亚表层组织,研究了超高锰钢的耐磨性和冲击磨料磨损行为.结果表明,冲击功为0.5 J和1.0 J时,碳含量较低的超高锰钢耐磨性与普通Mn13相当,碳含量较高的超高锰钢耐磨性高于普通Mn13;冲击功为2.0 J时,超高锰钢具有好的耐磨性,是普通Mn13的1.21倍,磨面硬度较高.超高锰钢冲击磨料磨损后磨损亚表层的变形组织主要由高密度位错和变形带组成,磨损亚表层的变形带相互交叉、截割.依据实际工况条件,加工硬化和冲击韧度适当配合的超高锰钢耐磨性良好. 相似文献
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GAO Bo HAO Sheng-zhi ZOU Jian-xin JIANG Li-min ZHOU Ji-yang'''' DONG Chuang .State Key Lab. of Materials surface Modification by Laser Ion Electron Beams Dalian China .Department of Materials Engineering Dalian University of Technology Dalian China 《材料热处理学报》2004,25(5)
MAGNESIUM ALLOYS exhibit high strength toweight ratio and stiffness and are finding theirapplications in air,automobile and electronic industries.Despite the worldwide growing interests inmagnesium alloys,their inferior wear resistance is aserious impediment.Considering that wear is asurface-related behavior,surface modification canresolve the problem.Recently,intense and pulsed energetic beams areemerging as new and effective methods for surfacemodification.The High Current Pulsed Ele… 相似文献