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。     

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。     

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。     

聚丙车间粉料振动筛电机基座箱体断裂失效分析

某聚丙烯车间粉料振动筛电机基座的箱体沿螺栓连接位置整圈裂开,并有断裂块体掉落下来,采用宏观检查、化学成分分析、硬度检测及金相组织检验等方法对此断裂块进行了综合分析。结果表明：电机基座断裂是由于电机转动时产生的高频振动使螺栓与基座螺栓孔相互撞击产生的疲劳、基座螺栓孔附近的奥氏体组织发生相变成为形变马氏体组织,使材料脆性变大导致断裂。     

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。     

0105W1T机头联轴器螺栓断裂及对策

０１０５Ｗ１Ｔ机头联轴器螺栓发生多次断裂事故，分析造成螺栓断裂的原因，提出对策性措施，介绍机头联轴器螺栓断裂的应急方法和拟进行的技改项目。     

磨机筒体与中空轴联接螺栓断裂的原因及防治措施

磨机筒体与中空轴的联接螺栓是磨机中的重要零件。运转过程中联接螺栓的断裂既影响水泥厂的生产又影响制造厂的信誉,是一个十分严重的问题。根据多年的生产经验我们制定了一些工艺措施把引起螺栓断裂的隐患消除在制造厂中。１．螺栓断裂原因的分析引起联接螺栓断裂的因素...     

法兰连接螺栓断裂失效分析及对策

某含硫集气站一进站流程双金属温度计法兰连接螺栓断裂，对站场安全生产造成影响，通过化学成分分析、腐蚀产物能谱分析、力学性能测试、断口形貌分析等检验方法对其失效原因进行分析，结果表明：螺栓的腐蚀断裂是由于阀门泄漏，含H2S天然气与螺栓接触后，在H2S环境下，螺栓发生了均匀腐蚀，在应力和硫化物耦合的作用下，螺栓发生了脆性断裂。针对螺栓腐蚀断裂的影响因素提出了具体对策。     

钻孔取丝专用工具的设计及应用

<正>我公司生料磨采用非凡MPS5000B立磨,2011年1月投产以来张紧拉杆装置运行正常,2017年4月拉杆上端钢球碎裂,更换钢球时压力框架上固定拉杆下球窝的一条螺栓断裂无法取出,根据现场空间设计了螺栓断裂取丝专用工具,最终将断裂螺栓取出。1故障状况拉杆下球窝结构示意见图1,下球窝通过M56螺栓固定到压力框架,螺栓断裂示意见图1。因断裂螺     

尿素合成塔塔盘塌陷原因及修复

分析尿素合成塔塔盘支耳断裂和塔盘塌陷的原因,制定塔盘支耳修复方法,讨论如何保证合成塔勾头螺栓和塔盘固定螺栓的安装效果,确保尿素合成塔的安全运行。     

胶合木外夹钢板群螺栓连接力学性能的试验研究

采用8组40个连接试件,考察胶合木外夹钢板群螺栓连接构件在顺纹受拉时的力学性能,探讨其破坏模式和受力机制。研究表明:胶合木外夹钢板群螺栓连接的破坏模式、承载力、刚度和延性与螺栓列数、每列的螺栓数、螺栓的布置方式有关;承载力不具有由螺栓数线性叠加的性质;螺栓总数不变、多列布置螺栓延性较佳。     

Reduced offspring production in bark beetleTomicus piniperda in pine bolts baited with ethanol and α-pinene,which attract antagonistic insects

Bolts of Scots pine,Pinus sylvestris L., attacked by the bark beetleTomicus piniperda (L.) were baited with ethanol and -pinene to attract antagonistic insects and thereby enhance their detrimental effects on the production of bark beetle progeny. Unbaited and caged bolts were included in the experiments as controls. Attraction of beetles to the bolts and subsequent emergence were estimated using traps. Six phloem-feeding species (potential competitors ofT. piniperda) and four predatory species were caught in significantly higher numbers at the baited bolts than at the unbaited ones. The number of offspring and the productivity ofT. piniperda were four to seven times higher in unbaited bolts than in baited bolts. Exclusion of other insects, by using cages, resulted in a nine-fold increase in the number ofT. piniperda offspring per square meter and productivity (offspring per egg gallery) compared with unbaited, exposed bolts.Hylurgops palliatus (Gyll.) (Scolytidae) andRhagium inquisitor (L.) (Cerambycidae) attacked both the baited and unbaited bolts, whereasAcanthocinus aedilis (L.) (Cerambycidae) andPytho depressus (L.) (Pythidae) reproduced almost exclusively in the baited ones. Large numbers of larvae ofThanasimus (Cleridae) andRhizophagus (Rhizophagidae) emerged from both the baited and unbaited bolts. Adults ofPlegaderus vulneratus (Panzer) andCylister linearis (Er.) (Histeridae) emerged almost exclusively from the baited bolts. The low progeny production ofT. piniperda in the baited bolts was attributed largely to the influence of adults ofRhizophagus andEpuraea (Nitidulidae), and larvae ofThanasimus andA. aedilis.     

Tensile behavior of hybrid multi-bolted/bonded joints in composite laminates

In composite structures, the strength of a standard single-lap joint with multiple bolts at best matches the strength predicted by the standard open-hole tension (OHT) test, which is about 50% of the tensile strength of the unnotched material. Although bonded joints do not have such limitation, they carry other drawbacks. The advantages of bolting and bonding may be combined in hybrid/bonded-bolted (HBB) joints. This study investigates HBB joints using carbon and glass-fiber reinforced composites with up to three bolts. It is found that multi-bolt specimens with or without adhesive fail in net-tension at the outer bolts like in OHT tests. However, HBB joint is not anymore limited by the OHT strength. The addition of the adhesive increases the strength of a three bolts joints by 70% for cross-ply laminates and 30% for quasi-isotropic laminates. The synergy between the bolts and the adhesive in the HBB system is interpreted by the fact that the outer bolts limit peel stresses and concurrently, the adhesive reduces the stress concentration around the bolts. This is particularly important for the cross-ply configuration where the stress concentrations around the holes are high. Other features observed suggest that for multi-bolted HBB joint, only external bolts are needed. Such joint configuration combines the safety provided by the bolts and the efficient load transfer provided by the adhesive.     

螺栓预拉伸法在聚酯熔体过滤器螺栓装拆作业中的应用

常规的螺栓拆卸方法常常造成过滤器的紧固螺母损坏、螺纹拉伤。采用螺栓拉伸法进行螺栓的拆卸和安装,可以非常有效地解决问题。文章对螺栓拉伸法在聚酯熔体过滤器螺栓装拆作业中的应用进行了介绍。     

浅析螺柱的疲劳校核

螺柱的疲劳分析，首先需确定螺柱承受循环载荷的交变应力强度幅。本文对其计算原理和方法作了介绍，并通过计算实例浅析螺柱疲劳设计的要点。     

氨合成塔主螺栓局部受损后的安全评定

对氨合成塔的主螺栓的损坏情况作了强度校核 ,有限元分析和安全性评定 ,提出可以继续承载的依据和运行中需注意的问题。     

High-temperature tensile properties and oxidation behavior of carbon fiber reinforced silicon carbide bolts in a simulated re-entry environment

The tensile properties and oxidation behavior of 2D C/SiC bolts prepared by chemical vapor infiltration were investigated in a simulated re-entry environment. The results showed that all the tensile strengths of 2D C/SiC bolts at test temperatures of 1300, 1600 and 1800 °C decreased, respectively, retaining 85%, 92%, and 94% of the virgin properties at room temperature. The tensile strengths and times to failure of 2D C/SiC bolts slightly increased with increase of test temperature from 1300 to 1800 °C. Microstructural observations indicated that the C/SiC bolts at lower temperature of 1300 °C were more susceptible to the reaction-controlled oxidation with the blunt fiber ends than those at high temperature of 1800 °C, which resulting in turn in great mechanical degradation and severe oxidation.     

汽车用厌氧螺纹锁固胶扭矩的影响因素研究

介绍了汽车用厌氧型螺纹锁固胶的固化机理,并以天山公司产品为例介绍了厌氧型螺纹锁固胶扭矩的影响因素,包括固化温度、固化时间、螺栓表面状态、螺栓类型、间隙等等,并与国外同类产品做了对比试验,     

压力容器垫片密封螺栓静强度安全系数的确定

基于信息熵理论中模糊等效随机的原理,将压力容器垫片密封螺栓的模糊静强度和模糊载荷等效为随机静强度和随机载荷,根据先漏后爆的观点和中国标准,分析了内压容器垫片密封螺栓模糊强度在不同工况时的许用可靠度,建立按许用可靠度确定螺栓静强度安全系数的方法。对于内压容器垫片密封结构,研究表明：①在预紧、正常操作、气压试验与液压试验时...