尿素振动筛驱动器底座装配形式的优化改进

针对尿素装置振动筛驱动器底座螺栓频繁断裂故障,结合振动筛的运行方式和结构特点,从振动筛驱动器与框架基座的装配形式以及紧固螺栓受力高频变化的特点入手,找到了螺栓频繁断裂的根本原因,并提出在振动筛驱动器底座加工定位凸台,框架基座加工凹槽,由凸台与凹槽配合受力以优化螺栓受力状态的改进方案。改进方案实施后,有效降低了螺栓因承受滑移交变剪切力而造成疲劳断裂的频率,防止了驱动器底座紧固螺栓松动现象的发生,确保了装置的正常运行。     

电厂旁路阀盖Inconel 718螺栓失效分析

针对某电厂旁路阀盖Inconel 718螺栓断裂事件进行失效分析。通过化学成分分析、宏观形貌和显微组织观察、力学性能测试和断口微观形貌观察等方法对螺栓的断裂原因进行研究。结果表明：裂纹是从螺栓一侧起始,在应力作用下扩展最终断裂。金相分析和扫描电镜分析的结果可知,断面附近螺纹根部较粗糙,组织存在混晶,开裂主要为脆性沿晶开裂。故螺栓断裂失效主要是由于存在混晶组织导致螺栓的脆性沿晶开裂。     

35CrMoV钢螺栓断裂原因分析

某石化厂汽轮机高强螺栓在检修回装过程中发生断裂。通过断口分析、金相组织分析、化学成分分析和力学性能测试等技术手段，对螺栓断裂原因进行分析。结果表明，螺栓材质不符合标准要求，冲击韧性低于标准要求。对断口进行分析后发现，螺栓在断裂前已经存在疲劳裂纹，疲劳裂纹形成的尖端应力集中是螺栓断裂的主要原因。     

风机变桨螺栓断裂失效分析

风机变桨螺栓作为风机变桨系统的重要紧固件在风力发电系统中发挥关键作用,但螺栓断裂事件时有发生。本文通过断口宏观分析、X射线荧光光谱分析、硬度实验、金相组织分析、力学性能实验等测试方法,对风机变桨系统变桨螺栓断裂样品进行了分析。研究表明螺栓断裂具有典型的疲劳断裂特征。螺栓疲劳性能的好坏对风机变桨系统能否正常运行具有重要意义。     

压缩机缸盖螺栓断裂原因分析

针对某低温压缩机缸盖上多个螺栓发生断裂的情况,采用断口扫描电镜分析、理化检验及力学性能测试等方法分析了螺栓断裂的原因。结果表明:断口形貌表现为腐蚀疲劳的特征,疲劳裂纹的起源为弱酸性介质造成的螺纹根部缝隙腐蚀,缝隙腐蚀使螺纹根部沟槽变得尖锐,应力集中变大,在振动作用下产生了腐蚀疲劳断裂。     

磨机衬板的螺栓断裂问题

我厂磨机衬板的螺栓断裂现象很严重,每次螺栓断裂都要停磨“堵孔”,不仅影响生产,而且对减速机等一系列机电设备都有影响。螺栓断裂的原因比较复杂,这里根据所掌握的材料,从受力、材质和加工方法三个方面做些粗浅的分析,以供参考。一、螺栓的受力状态绝大部分螺栓断裂,开始时均产生微小裂纹,裂纹一层层扩展,最后螺栓断裂。从断面上看,分为光滑和粗糙二个区域,断裂处无显著的塑性变形。这种断裂属于疲劳断裂。螺栓断裂的部位,大部分在与筒体外周相切的部位(见图1中A-A)。从螺栓断面以及断裂部位分析断裂原因如下。     

HRM1700立磨油缸底座振动的解决

2004年4月我厂投用1台H RM 1700生料立磨,不久即出现2个油缸底座螺栓松动频繁、底座振动较大的现象。运行至8月份,2个油缸各有1个地脚螺栓从底座螺孔处被剪断,至2005年4月,2个油缸底座连接地脚螺栓各断掉4个,磨机给料量一到40t/h,基础抖动,油缸振动强烈,严重影响磨机安全运行。原磨机油缸底座螺栓规格M 40m m×1 200m m。螺栓断裂均发生在油缸底座螺孔下方,而且最外围一行断裂的多。我们开始认为螺栓断裂和油缸底座混凝土浇注不密实、易使螺栓松动有关。但检查发现混凝土浇注密实,底板和基础结合良好。因此,我们推测螺栓断裂是由于螺栓数…     

球架锚固螺栓的断裂失效分析研究

某型号强度级别为10.9级的球架锚固螺栓发生断裂,该螺栓已使用了4～5年,通过材料化学成分分析、材料力学性能测试、断口分析以及金相组织检验等,分析了锚固螺栓断裂失效的原因。结果表明,锚固螺栓断裂方式为疲劳断裂,疲劳源位于螺纹根部应力集中区,为线性起裂源;弯拉工作应力叠加了一定的冲击波动载荷是螺栓发生疲劳断裂的主要原因,防护层破坏后螺纹底部发生腐蚀,在一定程度上促进了疲劳裂纹的形成。     

六角螺栓头防断裂改进措施

我公司2003年8月份安装一台Ф2.2×5.5m旧球磨机一台,运行中发现大齿轮对开合缝M36×180连结螺栓出现断裂现象,严重时一次断了四颗,影响磨机正常运行和生产任务的完成。经过分析研究,认为是螺栓头和光杆交接处直径陡然变化,应力集中造成螺栓断裂。笔者根据椭圆头护板螺栓的特点,取其所长,做成组合式螺栓头(如图所示)。先把六角螺栓上车床车成圆锥头,锥度在45°～50°左右,尾部平面铣一个改刀槽,以防转动。然后再车一个厚度30,外径75的锥孔垫圈与之配用。改进后的螺栓现已使用一年多,再没有出现螺栓断裂现象。改制组合螺栓头时,需考虑锥孔垫…     

提升机料斗螺栓断裂分析

正1存在的问题某水泥厂钢丝胶带提升机在使用过程中,料斗螺栓出现批量断裂现象,给生产造成困扰。该螺栓规格型号M14×70,材质45号钢,性能等级8.8级。经现场调研,提取断裂螺栓做金相分析,并随机抽取同批次库存螺栓送检第三方,组织技术人员对断裂     

“LOGO”在塑料机械中的应用

把可编程控制器“PLC”中“LOGO”集成块应用于塑料机械中,把可编程序输入到“LOGO”,来表达电器线路对塑料制品的记数和裁刀部分进行自动控制。     

工程塑料尼龙在机械零件中的应用

尼龙作为五大工程塑料之一,具有优异的力学性能、耐热性能、加工性能、电性能、耐溶剂性、阻燃性等,特别是浇铸尼龙被广泛应用于国防军工、工业机械、交通工具、民用机械等领域。综述了尼龙在国防、机械工业、交通工具等领域机械零件中的应用进展情况,并指出尼龙作为工程材料在很多领域应用非常广,但与国外的差距还很大,大多都只用在低速、轻载场合。塑料机械零件还未被企业和政府所重视,有少量应用,但产品质量落后于世界水平,尼龙机械零件的研究和应用还有很大的提升空间。     

Effect of the substrate temperature on the physical characteristics of amorphous carbon films deposited by d.c. magnetron sputtering

The growth rate, composition, electrical resistivity, mass density, refractive index and microstructure of amorphous carbon (a-C) films prepared by direct current (d.c.) magnetron sputtering were investigated as functions of the substrate temperature (50–350°C). The hydrogen content determined by elastic recoil detection analysis (ERDA) and the electrical resistivity of films were found to be dependent on both the base pressure in the deposition chamber and substrate temperature. For films deposited below 200°C, the hydrogen content was less than 2 at.% and the substrate temperature was the only parameter which affected their electrical resistivity. The electrical resistivity decreased from 0.2 to 0.03 Ωcm as the substrate temperature increased from 50 to 200°C. The mass density of films evaluated from Rutherford backscattering (RBS) data and film thickness decreased from 2.2 to 1.4 g cm⁻³ with increasing substrate temperature. A linear relationship between the refractive index and the mass density of a-C films was clearly established. From the optical measurements, the decrease in mass density was correlated to an increase in porosity of films with increasing substrate temperature. The decrease in electrical resistivity with increasing substrate temperature was attributed to a graphitization of a-C films. This modification of the microstructure of a-C films as the deposition temperature was varied from 50 to 350°C was observed by examination of the cross-section of samples by transmission electron microscopy and Raman spectroscopic analyses of a-C films.     

在役加氢反应器材料损伤分析

基于随加氢反应器运行 5a的试验试块 ,研究了加氢反应器运行 5a后筒体材料 2 .2 5Cr 1Mo钢的损伤。进行了化学成分分析、拉伸和冲击试验、脱氢和脱脆试验以及断口形貌分析。结果表明 :反应器运行 5a后筒体母材及其焊缝金属的拉伸性能未发生明显变化 ,而冲击韧性明显降低 ,且焊缝金属损伤程度较母材严重。经分析 ,材料的损伤主要是加氢反应器长期使用过程中高温回火所致     

参数化绘图在工艺装备设计中的应用

AutoCAD绘图软件具有强大的绘图功能，在产品设计中起着重要作用。在实际应用中。通常需要对AutoCAD绘图软件进行二次开发。在电机工艺装备设计中运用AutoLISP语言编写出绘制工装图的通用程序。当电机型号发生变化时，只需改变部分设计参数，即可形成新的设计图样，缩短了电机工装设计的时间。提高了设计效率。     

我国塑料机械的安全标准及安全性能的现状和发展

详细阐述了目前国内外塑料机械安全标准的现状,详细分析了我国塑料机械产品存在的防护装置设计问题、安全装置设计问题、电气安全问题、热防护及安全标志问题等,并对我国塑料机械安全标准的发展提出了建议。     

In situ polymerization of aniline in the presence of carbon black

A hybrid material of polyaniline doped with dodecylbenzenesulfonic acid and conductive carbon black (PaniDBSA/CB) was prepared by in situ polymerization. The presence of low amount of CB (up to 25 wt %) resulted in a decrease in resistivity as compared to pure PaniDBSA. Composite with 25 wt % of CB presented the lowest resistivity and a tubular morphology characterized by microtubules with high aspect ratio evidenced by SEM examination. Higher amount of CB give rise to materials with higher resistivity values and a granular morphology, similar to pure carbon black. Ultraviolet–visible and electron paramagnetic resonance analyses were employed to evaluate the polaron concentration. X‐ray diffraction was used to characterize the molecular structure of these composites. It was observed a decrease in the crystallinity degree and a shift of the polaron band transition toward lower wavelength as the amount of CB in the composite increases. From the EPR measurements, one can suggest that the higher chain order and polaron mobility is observed in hybrid with 25% of CB. This behavior is in agreement to the electrical resistivity values and SEM microscopy. The effect of CB on thermal stability of the composites was also investigated. The effect of the PaniDBSA/CB hybrid material on the processability and resistivity of the composites based on styrene‐butadiene‐styrene (SBS) block copolymer as the insulating matrix have been also evaluated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 535–541, 2006     

氯化聚醚丁腈橡胶的性能、特殊配合及应用

介绍了氯化聚醚丁腈橡胶（PNBR）的性能、特殊配合技术及在煤碳、石油、化工、电器、医疗、机械、航空和军事工业中作密封、防腐、耐磨、电绝缘等的应用。     

Processing dependency of percolation threshold of MWCNTs in a thermoplastic elastomeric block copolymer

We prepared carbon nanotube thermoplastic elastomeric block copolymer nanocomposites using a commercial styrene-ethylenebutylene-styrene (SEBS) block copolymer and multiwall carbon nanotubes (MWCNTs) at different filler concentrations. Hereto we applied two different processing strategies, namely direct melt mixing and solution-precipitation. We observe that the mechanical and electrical properties such as storage module and electrical percolation threshold are clearly affected by the processing approach. We studied these effects in detail by means of dielectric spectroscopy, which provided important information about the dispersion state of the MWCNT filler network. It revealed a fractal filler behaviour of the samples independent of the processing method. However, in samples prepared by melt mixing an additional dielectric response related to nanoscopic gap junctions of 1.5 nm was identified. This response was not present in solution-mixed samples, which are characterized by improved polymer wetting. We discuss how the interactions between CNTs and the two phases of the block copolymer matrix are affected by the processing conditions resulting in the important differences in the filler network structure, which directly influence the final electrical and mechanical properties of the composite.     

农业机械表面涂装工艺及其展望

近年来，我国农业机械在表面涂装技术领域里，引起了人们十分关注，它由一个落后状况发展到与国际标准相差无几的高水平，如大型农机中的联合收割机在涂装方面就有一个特大的飞跃，本文以它的涂装工艺为例，相应地反映出我国农机涂装的现状及其未来。