对塑性变形修复工艺的探讨

塑性变形修复工艺是修复建筑机械零件的一种有效方法,笔者根据国内外资料和实践经验,就塑性变形修复工艺中的一些问题,提出一孔之见,与同行们切磋。一、工艺特点塑性变形修复工艺是对金属零件局部加热(或加压)后获得塑性变形来抵消零件的超差变形或补偿磨损的修复方法,从金属学的观点看,塑性变形的实质是金属晶面产生滑移。     

农用机械检修要点

<正>近年来,农机修理工作发展迅速,旧的修复工艺日趋完善,新的修复工艺不断涌现和逐步推广,取得了很大的成绩。由于可修复的零件种类繁多,要求各不相同,因此零件的修复方法必然也多种多样,并在不断的发展之中。可见,尽可能地采用各种修复工艺来修复旧件,对加速农业机械化事业的发展具有很大意义。在农机各类零件中,有修复价值的零件占相当大的比重。搞好农机旧件修复,不仅可以及时满足对配件的需要,加快修理速度,降低修理成本,保证     

改善修复件终加工工艺的途径

建筑机械修复件终加工工艺(以下简称终加工工艺)是修复工艺的最后工序。它的成败直接影响修复件的质量,据苏《有前途的零件修复法和强化法》一书介绍,由于终加工工艺失误而产生的修复件缺陷占修复件缺陷总数的15.7%。另外,终加工工艺的经济性也直接影响修复成本。所以,它是修复工艺中重要的一环。它的经验还可作为加工新零件借鉴。一、终加工工艺的作用终加工工艺的作用如下:1.使修复件达到规定的几何形状和尺寸。2.使修复件的精度和粗糙度达到规定的级别。3.使修复件的强度、耐磨性等机械性能达到或超过新件标准。     

《机械修理学讲座》——第七讲 零件修复方法

§1 概述一、提高零件修复效益的途径组织专业化的修旧厂或修旧车间,对社会开放,专门修复某几种零件或专门采用某几种工艺修复各种零件,由于生产单一,生产批量又大,可以使修复件的价格低、质量好,寿命长。如武汉某汽车旧件修复厂,坚持修旧已几十年,别人认为金属丝气喷涂已属于陈旧淘汰的工艺,而他们用喷涂修复曲轴效果很好;又如镀铁工艺,在生产批量小     

机械旧件修复十工艺

问题的提出建筑机械的工作环境十分恶劣，机件较容易磨损，维修时经常要更换不少失效零件。这些零件大多数是局部损坏或表面丧失某些技术性能，只需经过恰当的修理工艺就能修复。这与制造或新购零件相比，其修旧成本费用相对较低，尤其对价格昂贵、形状复杂的大型零部件经济效益更为明显。因此，设法修复越来越多的失效旧件和报废件将是一笔不少的财富，在目前的形势下显得更重要。２常用修旧工艺我公司维修工厂根据现有加工设备及技术力量进行修旧利废，总结有焊、粘、镶、缩、配、驳、磨、铰、改、铆十种修旧经验，现将基本工艺简介如下。…     

电刷镀技术在修复大型设备中的应用

电刷镀技术是近代发展起来的用于修复机械零件的一门新技术。本文通过用电刷镀技术修复大型设备零件严重磨损的实践，详细介绍了这一技术的工艺流程，并对工艺过程中的几个问题进行了分析和说明。     

零件修复的发展前途和发展方向的探讨

问题的提出我国零件修复的发展经历了曲折的道路。五十年代和六十年代初期,由于缺乏先进的修复工艺手段,只能采用粗简的工艺进行低质量修复;或者根本不修,以新换旧。后来,由于配件供应紧张,加上先进工艺的引进,零件修复发展很快,特别是1975年全国农机修理技术革新展览以后,零件修复工艺迅速推广,遍地开花。但是,最近由于配件供应好转和其他多种因素的影响,零件修复又进入了低潮,不少企业中刚刚搞成的低温镀铁,氧——乙炔火焰喷涂,电火花磨削等新工艺惨遭冷落。因此,     

铝料仓制造施工技术

以掺混料仓为例，对铝制料仓的制造从组装工艺方案、成品保护、工装胎具的使用以及铝合金的焊接几方面进行了控制，保证了产品质量。     

吊车断裂弹簧钢板的焊接修复

吊车上的板弹簧是一个很重要的零件，它在反复应力下工作，承受较大的冲击负荷和振动，要求其应具有较高的疲劳强度、抗拉强度等性能。由于板弹簧为碳含量较高的合金钢，焊接性差，修复断裂的板弹簧较困难。某公司的一台日本进口TL-252型25t吊车，在使用二年内先后发现五块弹簧钢板断裂，给现场施工带来了不便和一定的经济损失。经制定严格的工艺，对断裂板弹簧成功地进行了焊接修复，修复后使用效果很好。     

电动汽车电池包箱体保温性能研究与优化

本文以纯电动汽车的动力电池包钢制与铝制箱体为研究对象,利用传热学相关理论对电池包箱体进行分析,得出了电池包保温性能的影响因素.应用Catia软件中的创成式模块和零件设计模块对钢制与铝制电池包箱体进行了三维建模,为仿真分析提供了几何模型.并在Hypermesh软件中对电池包箱体三维模型进行网格划分,构建出有限元热分析的网格模型.运用Taitherm软件采用热流耦合的方法对电池包网格模型进行仿真计算.根据仿真计算结果对钢制与铝制电池包箱体的保温性能进行了对比研究并对不同的保温设计方案进行了优化.     

水泥磨3000kW主减速机空心齿轮轴配铰孔加工技巧

工装是机械制造过程中的重要组成部分,它能巧妙利用现有设备加工零件,并能保证零件的加工质量,尤其在水泥机修厂中能解决生产中急需的备品配件修理问题。文中叙述了如何利用工装扩大现有加工设备的范围来对水泥磨3000kW主减速机空心齿轮轴及其连接件进行配合铰孔及钻孔攻丝。     

用碳/环氧和石墨/环氧片修复半圆凹槽边缘裂缝有效性的比较

粘结复合材料片修复技术可以有效地用于加固或延长带裂缝铝结构的使用寿命。采用有限元方法分析在半圆形侧向凹槽处粘结不同复合材料片用于裂缝修复的性能。相邻裂缝处的应力分布对于根据片材几何尺寸进行的修复分析是很重要的。力学和几何性能对裂缝尖端处应力集中系数变化的影响显著。粘结剂性能和片材尺寸对I型模型中裂缝尖端处应力集中系数变化的影响也很显著。并进行了双片和单片修复的比较。结果表明双片修复时的裂缝尖端应力集中系数比单片修复时的裂缝尖端应力集中系数减少一半,具有高刚度的纤维走向垂直于裂缝走向时显著地降低应力集中系数。为了提高片材修复或加固性能,必须进行粘结剂性能的优化。     

A new lightweight metal-composite-metal panel for applications in the automotive and other industries

A new lightweight metal-composite-metal (MCM) panel is developed. This panel consists of two layers of 0.2-mm thick stainless steel sheet with a layer of woven fabric (semi-flexible composite) in between. The stiffness and the dent resistance of this MCM-panel are compared to those of corresponding panels pressed in 1-mm thick aluminium, 0.8-mm thick carbon steel and 0.8-mm thick stainless steel sheets. Compared to the aluminium panel, the MCM-panel exhibits a slightly smaller stiffness. However, the MCM-panel displays a larger dent resistance than the aluminium and the carbon steel panels. The new panel is 46% heavier than the aluminium panel. However, it is 60% lighter than the carbon and stainless steel panels. This new panel is expected to have many applications in manufacturing of parts for car, train and bus bodies, appliances and household machines. Machine chassis and air cargo containers are other examples of products, in which the new panel can be used. Production of the new panel requires that the tools be heated. The cycle time is short, since a newly developed and patented method for ultra-rapid heating of tools has been used in this study. The production is economical, since the cycle times is short and recycled fibres can be used. The production process is not completely optimized yet. However, the conducted experiments show that the panel stiffness and dent resistance are benefited, if the tool pressure applied during the heating is low.     

水泥混凝土路面快速修补材料的研制

利于硫铝酸盐水泥和普通硅酸盐水泥及高效减水剂等配制水泥混凝土路面的快速修补料,根据路面修补的要求配制了修补混凝土和修补砂浆,并测定了修补材料的抗压强度,水化放热,磨耗量等指标,分析了修补材料的特点和施工工艺要求,可以应用于水泥混凝土路面的修补。     

塑料推拉窗型材模具设计与调试

提出了塑料推拉窗型材模具的设计原则，阐述了模具的工作原理、结构、制造工艺及主要设计参数，着重介绍了主要零部件的设计方法，总结了模具调试的经验和修整方法。     

三元复合超早强掺合料的配制及应用

利用硫酸盐、亚硝酸盐和活性掺料粉末等原料配制出了能够明显改善混凝土的早期强度、且不会对混凝土耐久性产生不利影响的三元复合超早强掺合料。使用快硬硫铝酸盐水泥、氨基苯磺酸系高效减水剂及研制的掺合料配制的路面修补混凝土,和易性好、5h抗折强度达到3.7 MPa,并具有良好的界面粘结性能和抗冻性能,在实际工程修补应用中取得了很好的效果。     

上海世博和谐塔风荷载参数数值风洞模拟

采用数值风洞技术数值模拟上海世博和谐塔的绕流场,获得了三维复杂结构的绕流场和风荷载参数。充分结合现有的计算技术和硬件计算能力,把整体结构的数值模拟分解为核心圆筒加外围弧形铝板部分,以及桁架体系部分。利用前者得到的等效局部风环境来评估桁架体系的风荷载,从而得到整体的风荷载参数。通过与物理风洞的试验结果进行对比可以认为数值风洞的结果是可信的。     

Using a geotextile with flocculated filter backwash water and its impact on aluminium concentrations

The use of geotextiles (i.e. geotextile tubes) in wastewater treatment applications is ever increasing. This paper examines the potential of using a geotextile to improve upon the treatment of aluminium present in a filter backwash water that is generated from a water treatment plant in Halifax, Canada. A field investigation to ascertain the distribution of aluminium in the filter backwash water treatment process is provided and compared to regulatory guidelines at the environmental compliance point. It is shown that aluminium is undergoing incomplete treatment at various times throughout the year. To examine a potential corrective action, the results of bench scale studies are presented in which cationic additives (i.e. CaO, MgO, and Fe₃O₄) are combined with a polymer to remove aluminium from solution and flocculate particulate matter from the filter backwash water. A geotextile is utilized to retain particulate matter generated from this process. It is shown that the combined use of the cationic additive with polymer can successfully reduce aluminium concentrations in the filter backwash water and that filtration via a geotextile can retain the aluminium particulate in the filter backwash water to levels close to regulatory requirements. Further optimization with the flocculation process is recommended prior to pilot testing.     

Experiments aimed at the removal of phosphate by electrochemical methods

An electrolysis cell with separated electrode compartments was used to measure in different electrolyte solutions the amount of aluminium dissolved electrochemically in the anolyte by 1 A current during 1 min. This was found to be more by 10–20% than that predicted by Faraday's law.

Owing to alkalinization of the electrolyte in the cathode compartment of the divided electrolysis cell the cathode was found to be dissolved chemically, the process being unaffected by the intensity of the current passing.

The electrochemical dissolution of aluminium was found finally to be more efficient in removing phosphate from both the model solution and the sewage than the same amount of aluminium contained in an aluminium sulphate solution used for chemical precipitation if the molar ratio of aluminium to phosphorus was greater than about 1.6.

A probable explanation for the higher efficiency of electrolytically produced aluminium ions is that as opposed to aqueous solutions where aluminium is present in the form of aquo-complexes, the electrolytically produced species uncomplexed ‘nascent’ aluminium.     

Bridge Maintenance Level Assessment

Parameters in assessing the effectiveness of maintenance tasks on the overall cost of a bridge or system of bridges are identified and the linkage among maintenance, condition rating, and cost is made by subdividing the subjective process into smaller parts. Experience with New York City bridges is used to develop a life expectancy model once the maintenance and repair protocol is specified. Results for several sample maintenance allocations are given to show how a rapid spreadsheet calculation can provide a basis for comparing maintenance alternatives and to point in the direction of an optimized allocation of limited budgets.