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1.
轧制塑性变形对W-Cu复合材料组织性能影响   总被引:1,自引:0,他引:1  
于洋  于欢  张文丛  王尔德 《粉末冶金技术》2013,31(3):163-166,173
对不同Cu含量[20%~50%(质量分数)]的热挤压后的W-Cu合金坯料进行轧制,通过对比得出最佳轧制工艺参数,并制备出微观组织均匀、致密度高、性能优异的W-Cu合金板材。结果表明:轧制力随着道次轧下量的增加而逐渐增大,并且当一次轧下量超过60%时,轧制力急剧增加;随着轧制变形量的增加,Cu相发生变形,W相形状基本不发生变化,但W相有细化的趋势;轧制变形能在保持W-Cu合金热挤压后高组织均匀性、高致密度、高性能的基础上获得薄板甚至是箔材。  相似文献   

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对于斜轧机,使用阶梯形轧制方式,能有效地改善咬入条件并减少轧件尾卡的可能性。本文介绍这种新型轧制方式的控制系统软件包及其主要功能。成都无缝钢管厂φ250mmAccu-Roll轧管机组的实际运行结果表明,该控制系统灵活方便,运行可靠,提高了作业率和钢管成材率,取得了较好的经济效益。  相似文献   

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A one-dimensional mathematical model for powder materials on a metal substrate rolling process has been developed on the basis of a numerical recurrent solution of static equilibrium conditions in the finite difference form for a specified elementary volume of metal. The correct account of the laws concerning the relative density distribution, mechanical properties, and econometric parameters, and also the presence of the elastically deformed metal substrate in the deformation confinement volume are the peculiarities of this model. Translated from Poroshkovaya Metallurgiya, Nos. 1–2(411), pp. 13–21, January–February, 2000.  相似文献   

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For ultra-thin strip rolling, the conventional rolling force models are no longer applicable. To obtain accurate rolling force in the shape and gauge control process, Fleck proposed a new roll flattening model. In this study, experimental analysis, finite element simulation, and theoretical analysis were conducted to evaluate the Fleck model. The experiments and simulations show a clear neutral zone in the deformation zone with decreasing strip thickness. The finite element simulation results show that the proportion of the elastic unloading zone is small, when an elastic unloading phenomenon appears in the neutral zone. Thus, to simplify the rolling force model, the effect of an elastic zone could be ignored. Based on this finding, we develop a rolling force model with quick calculation speed, high precision, and convenient online application. Finally, the accuracy of the simplified model is verified by the measured rolling force.  相似文献   

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Conclusions On the basis of a comparative analysis of results of numerical experiments carried out by various methods, it is shown that the method proposed by the authors is well suited for practical calculations, with the aid of a computer, of the power and force parameters of the cold rolling of strip. In the present stage of development of cold rolling as a process for the manufacture of powder metallurgy strip, the method could be used for providing starting data in the design of the mechanical units of metal powder rolling mills.Translated from Poroshkovaya Metallurgiya, No. 7(151), pp. 11–21, July, 1975.  相似文献   

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大断裂区域片岩地层巷道围岩大变形类型与机理研究   总被引:1,自引:0,他引:1  
通过对大断裂区域片岩地层巷道工程中出现的大变形问题进行分析研究,将大变形类型划分为岩性决定型、结构决定型、地形偏压型和爆破扰动型。在对大变形形成机理分析的基础上,提出了综合治理措施,现场应用中取得了良好的效果,可为矿山等其它类似地下工程施工提供借鉴。  相似文献   

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对悬臂轧机油膜轴承烧坏的原因进行全面分析,并提出相应的管理对策.  相似文献   

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采用被动式工艺生产冷轧带肋钢筋须经过减径、成型两台轧机连续轧制.要求钢材的秒流量相等,否则将造成断线停产或线材在拉丝机卷筒上打滑,致使卷筒严重磨损.用双层卷筒拉丝机提供动力生产冷轧带肋钢筋时,线材直径与卷筒直径的匹配是在一个小的调整范围,通过轧机拉力控制在一定范围变化,可保证成品尺寸符合公差要求而不产生打滑,从而避免了卷筒严重磨损.  相似文献   

12.
电磁振动雾化速凝金属镁粉的表征分析   总被引:1,自引:0,他引:1  
通过用电磁振动雾化-速凝法制备了粉粒度小于0.5 mm的镁粉,研究了这种速凝镁粉在1 000℃的阻燃时间.结果显示,速凝镁粉阻燃时间为17~21 s,而铣削-钝化镁粉阻燃时间为11~14 s.用x射线衍射的方法,检测和计算了速凝镁粉的晶面间距和晶面指数.速凝镁粉的结构属于JCPDS卡片,卡号:4-770,镁的密排六方晶体结构,a=3.209 5 A,c=5.210 4 A,其密排六方结构未因电磁振动雾化-速凝制备方法而改变.  相似文献   

13.
本文通过一步烧结法制备了三种不同含碳量的WC-Ti(C,N)-(Ti,W)C-(Ta,Nb)C-Co脱β层硬质合金,通过扫描电镜(SEM),电子探针微区分析仪(EPMA)分析合金的微观组织和成分分布,以及测定维氏硬度HV30,断裂韧性KIC等性能指标,研究碳含量对其微观组织和物理力学性能的影响,研究结果表明:在三个合金的表层均形成了缺Ti,Ta,Nb的立方相,而富Co粘结相的脱β层。微量的C含量变化对合金的组织和性能产生重要的影响,合金的脱β层厚度和WC的平均晶粒度均随着C含量的增加而增大。随着碳含量的增加,维氏硬度HV30降低,断裂韧性KIC增加。  相似文献   

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"The purpose of this study was to determine whether a participatory style of leadership was more effective than a lecture style of leadership in inducing an attitude change when the leader explicitly offered to reward compliance or threatened to punish noncompliance. 35 groups of 4 to 8 pupils in the fifth and sixth grades of a public school met with a leader who tried to change their preferences for comic books. 6 experimental conditions were established… ." Among the results were the findings that both reward and punishment produced more public compliance than the control conditions and that participatory leadership induced more change than lecture leadership when the leader was associated with neutral power or power to reward compliance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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通过对国内外不同矿点炼焦煤变质程度、胶质层指数Y值、奥亚膨胀度b值、高温塑性、煤岩显微组分和成焦光学组织结构分析研究,发现变质程度、胶质层指数Y值和奥亚膨胀度b值相同或极其接近的炼焦煤高温塑性和单种煤成焦光学组织结构差异悬殊。其原因不在于镜质组含量的高低,而在于成因因素造成的镜质组性质不同。指出,胶质层指数和奥亚膨胀度指标在表征其结焦性时存在局限性,高温塑性和单种煤成焦光学组织结构对炼焦煤结焦性的科学评价至关重要。  相似文献   

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"The present study sought to determine how a player in different positions of relative power could exercise this power in the form of various game playing strategies so as to induce an individualistic S to adapt to a cooperative orientation." The greater the power S experiences over another, the more trusting he can permit himself to be; S will respond differently to varying degrees of co-operativeness in another under conditions of equal power. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

17.
The variations of optical density and fluorescence of lucensomycin are good indices of the binding of this polyenic antibiotic to membranes. The former parameter reflects more generally the binding to any site present in the membrane, while the latter is more specific for binding to cholesterol. The chromophore of the lucensomycin-cholesterol complex has a relatively long lifetime, is almost immobile in the membrane, and is not accessible to water-soluble fluorescence-quenching agents. The stoichiometry, evaluated fluorometrically, corresponds to about two cholesterol molecules per polyene. In colloidal cholesterol suspensions, the extent of binding as a function of free polyene concentration is described by rectangular hyperbolae, the dissociation constant being, however, dependent on the sterol concentration. In erythrocyte membranes, on the other hand, and even more markedly in model systems containing appropriate solvents, the combination between lucensomycin and the sterol sites is described by sigmoid titration curves, indicative of cooperative effects, and probably due to solvation of cholesterol.  相似文献   

18.
粗金粉(Au含量70%~80%)和粗银粉(Ag含量90%以上)混合熔铸成含金较高的阳极(Au:Ag≈1:3),采用一次电解工艺分离提纯,最终产品金锭成色>99%,银锭中银含量>99.9%.工艺过程简单,投资操作费用较低.  相似文献   

19.
A 9-year-old male child had a IV ventricular medulloepithelioma of classical histology, showing tubulopapillary and undifferentiated areas. The unusual feature, however, was the presence of melanin pigmentation in the cells, which was further confirmed by electron microscopy. So far 28 cases of medulloepithelioma have been reported in the English literature. However, none of them showed melanin pigmentation. To the best of our knowledge this is the first case of pigmented medulloepithelioma in the English literature.  相似文献   

20.
翟爱霞  王佳 《粉末冶金技术》2012,30(3):219-222,228
采用酒石酸钾钠为络合剂、抗坏血酸为还原剂还原硫酸铜制备了微米级Cu粉,并考察了抗坏血酸溶液浓度、反应温度、酒石酸钾钠的用量对Cu粉微观形貌的影响,通过SEM、XRD对Cu粉进行表征。结果表明:制备的产品为类球形或多面体的纯Cu,粒径范围为1.3~6.0μm;随着酒石酸钾钠用量的增加,Cu粉粒径先减小后基本不变;升高反应温度,增大抗坏血酸溶液浓度,均能使Cu粉粒径增大。  相似文献   

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