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25MnV钢矿用高强度圆环链的中频感应加热淬火 总被引:4,自引:4,他引:4
研究了25MnV钢矿用高强度圆环链在中频感应淬火加热时链环的温度分布、淬火后链环顶部的金相组织以及不同淬火温度下链环晶粒度的变化规律。结果表明,25MnV钢矿用高强度圆环链在中频感应淬火加热时,链环直臂温度比顶部温度低。链环顶部加热温度达到970~993℃时(直臂温度为895~917℃),淬火组织为板条马氏体,晶粒度为10~10.5级,圆环链有最佳强韧性配合。当顶部加热温度达1017℃时,淬火组织及晶粒度明显粗化,导致力学性能恶化。 相似文献
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矿用高强度圆环链是煤矿井下工作面刮板运输机、滚筒采煤机和巷道掘进机的一个重要传动部件,承载能力大、使用率高,其性能与质量的好坏直接影响着煤矿井下的安全,因此要求圆环链必须具备合理的几何尺寸和良好的力学性能. 相似文献
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23MnNiMoCr54钢是制造高强度圆环链链条的主要材料,原材料为退火状态,经过编环-焊接-调质热处理后制成煤矿运输机械高强度圆环链链条.根据圆环链链条的使用状态,对原材料的化学成分、组织均匀性、硬度均匀性、力学性能提出了相应的严格要求,以满足矿用圆环链用钢对下料、弯曲、焊接等工艺性能的要求.23MnNiMoCr54钢是德国牌号,在20世纪80~90年代以前主要依靠从国外进口,从20世纪90年代以后,国内有钢厂按德国牌号成分要求进行小批量试制,但是,尽管成分和日本生产的钢材相近,用国内的钢材制作的圆环链,疲劳寿命偏低. 相似文献
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讨论矿用圆环链漏磁探伤机理,并对其漏磁特性进行了较为洋细的分析.在实验基础上给出了矿用圆环链缺陷漏磁场磁感应强度B与缺陷特征尺寸的关系,同时给出了矿用圆环链缺陷漏磁场强度H的计算方法. 相似文献
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矿用圆环链(图1)是用20Mn2圆钢闪光焊接的。每条链由15个链环组成,要求抗破断力在41吨以上。热处理工艺为850℃淬火,250℃回火。经上述处理的链条在破断试验时,95%以上断裂在焊缝处,达不到设计要求。曾多次改变热处理工艺,结果仍在焊缝处断裂。对焊口金相分析表明,焊口处明显地分为 相似文献
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随着采煤、挖掘和运输机械化的发展,对刮板输送机和刨煤机的重要配件之一——矿用高强度圆环链的性能也提出了越来越高的要求。尤其是需要量最大的φ18mm×64mm矿用高强度圆环链,其C级链除了要求具备高强度外,还要有较高的塑性和韧性。焊接是制造C级链的关键工序,一般采用焊接接头质量很好的预热闪光对焊方法。 相似文献
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齿形链链板级进模设计 总被引:2,自引:2,他引:0
分析了齿形链链板的冲压工艺,介绍了零件排样、模具结构与工作过程及模具关键零件设计。实践证明:模具设计合理,操作简便,生产效率高,能满足零件质量和生产要求。 相似文献
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722联结环是用于煤矿井下的关键部件,要求有很高的抗拉性能和抗疲劳性能。采用原有成形工艺经常产生折迭、充不满等诸多问题。为了解决这一问题本文采用DELFORM 3D塑性有限元模拟分析系统,建立了722联接环热成形工艺的刚塑性有限元模型,用三维有限元法对722联接环成形工艺进行了模拟分析,预测成形缺陷的产生,针对原有工艺出现的问题进行了改进及优化。模拟发现,采用原工艺的平底仓部,不利于金属向四周排除,且金属流动激烈,易产生缺肉和折迭,致使锻件报废。基于模拟分析结果,在终锻模膛中采用带仓连皮,从而有效地避免了折迭的产生,减小了坯料的尺寸,使材料利用率大大提高,而且由于连皮周边较薄,易于冲除,提高了切边模模的寿命。 相似文献
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Bashar S. El-Khasawneh Placid M. Ferreira 《International Journal of Machine Tools and Manufacture》1999,39(2):1552
Parallel link spatial mechanisms in general, and Stewart Platforms in particular, are increasingly being studied for possible use in multi-axis machine-tools. An important consideration in the design of such machines is their stiffness. For a given design, stiffness varies with the direction in which it is computed, the posture (or configuration) of the mechanism and the direction of the actuation or disturbing force. This paper addresses the problem of finding the minimum and maximum stiffnesses and the directions in which they occur for a manipulator in a given posture. In addition, the computation of stiffness in an arbitrary direction is also discussed. Since engineers are often interested in the response of the mechanism in the direction of perturbation (called single-dimensional or engineering stiffness in this paper), this paper proves the computed bounds (maximum and minimum) are tight for such a definition. Stiffness computed using the algebraic formulae derived are compared to those obtained from a Finite Element Analysis model to demonstrate correctness of formulation. Finally, minimum, maximum, arbitrary direction and single-dimensional stiffness maps, are produced for a Stewart Platform and their use in machine tool design is discussed. 相似文献
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Péter Dusán Ispánovity Ádám Hegyi István Groma Géza Györgyi Kitti Ratter Daniel Weygand 《Acta Materialia》2013,61(16):6234-6245
Micron-scale single-crystalline materials deform plastically via large intermittent strain bursts that make the deformation process non-deterministic. Here we investigate this stochastic phenomenon by analyzing the plastic response of an ensemble of specimens differing only in the initial arrangement of dislocations. We apply discrete dislocation dynamics simulations and microcompression tests on identically fabricated Cu single-crystalline micropillars. We find that a characteristic yield stress can be defined in the average sense for a given specimen ensemble, where the average and the variance of the plastic strain start to increase considerably. In addition, in all studied cases the stress values at a given strain follow a Weibull distribution with similar Weibull exponents, which suggests that dislocation-mediated plastic yielding is characterized by an underlying weakest-link phenomenon. These results are found not to depend on fine details of the actual set-up; rather, they represent general features of micron-scale plasticity. 相似文献
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本文介绍了应用三菱开发式现场总线CC—Link建立数控车间总线控制网络的关键技术问题。着重介绍了数据链接指令的使用及主站和本地站程序编制要点。 相似文献
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<正>SS7E型电力机车的传动装置采用一级直齿圆柱齿轮传动,把牵引电机产生的转矩,通过从动齿轮上的6个连杆销传至六连杆空心轴,再通过主车轮的6个连杆销传到轮对,使轮对转动。连杆销是轮对上的重要零件,对机车的运行安全起着至关重要的作用[1]。SS7E电力机车的连杆销材料为35CrMoA钢,要求调质硬度270~300 HBS,表面渗氮硬度≥560 HV5,渗 相似文献