共查询到20条相似文献,搜索用时 140 毫秒
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针对液压起重机缸的活塞杆在使用过程中发生的断裂失效,采用扫描电子显微镜(SEM)、能谱仪和硬度检测仪等方法研究了断口形貌及局部位置的成分进行了分析,确定了裂纹源的位置和形成机理,并对断裂的原因进行了分析。结果表明:钢中的非金属氧化物夹杂、第二相粒子是活塞杆疲劳断裂的的主要裂纹源。活塞杆在交变载荷的作用下,在缺口敏感度较高的螺纹切口处产生疲劳断裂。 相似文献
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通过对宏观断口、微观断口的观察,并采用电子显微镜、扫描电镜、能谱仪等仪器对显微组织及力学性能进行分析,并对往复压缩机活塞杆断裂的原因进行分析。结果表明活塞杆的断裂属于早期疲劳断裂,为脆性断口,其裂纹源位于台肩根部的次表皮。由于原材料在锻造时局部形成了粗大晶粒的原始组织,并伴有混晶和微裂纹,而且台肩R处加工时应力集中和加工精度不高,促进了活塞杆断裂的发生。 相似文献
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公司装配流水线液压升降平台的液压活塞杆,有时因使用、设计和加工工艺不当等原因,致使从顶端断裂,从而造成生产中断。结合液压活塞杆的焊接特性和液压油缸缸体密封的问题,经分析采用直径3.2mm的E5015焊条,焊前不预热焊接,制定了焊接工艺,改进了传统焊接方法。后经使用,效果良好。 相似文献
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空压机活塞杆断裂分析 总被引:1,自引:0,他引:1
利用光学显微镜与扫描电镜对失效的空压机活塞杆的组织与断口进行了分析。结合力学性能测试结果得出,活塞杆失效属于疲劳断裂。造成疲劳断裂的原因是活塞杆存在较多未溶铁素体及加工时刀痕过深形成较大的应力集中。 相似文献
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堵亦民 《锻压装备与制造技术》1982,(6)
我厂有一台济南第二机床厂1970年出厂的JA36-800吨压力机.在1979年8月,因冲裁8毫米厚的锰钢板,在右平衡气缸的活塞杆下端退刀槽处断裂.整个活塞和活塞杆一起冲出气缸.经过分析认为,产生断裂的原因:一是当冲裁厚度较大的板料时,机器振动十分严重;二是原结构活塞杆的强度较差(现制造厂已经改进),受力时变形较大,活塞杆极易断裂.为了缩短修复机器的时间和费用,我们利用原来零件,并局部改进结构的办法进行修复.具体做法是:将活塞杆断裂端车成M60-段螺纹.另外再接长一段活塞杆,使螺纹退刀 相似文献
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设计和制备了孔隙率不同的3组规则多孔钛试样,采用分离式霍普金森压杆实验装置,开展了应变率范围在600~2100 s-1的单轴压缩实验,研究了加载过程中整个试样和局部孔洞的变形失效特征。结果表明,试样展示出2种典型的变形模式:压缩变形模式和连通断裂模式。压缩变形模式主要发生在低孔隙率的试样,试样的外表面胞壁出现局部塌陷,而连通断裂模式易发生在高孔隙率的试样中,常在试样的一个或多个孔层出现连通的断裂。另外,2种变形模式下的局部孔洞也呈现出不同的形状变化特征,且在孔洞最小曲率的位置都形成明显的应力集中,相应的应力集中因子随试样孔隙率的增大而增大。微结构分析显示:剪切带是试样失效的主要机制,试样的断口容易产生韧窝和韧性条纹。 相似文献
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Modern blue flame burners are equipped with a flame tube that serves for recirculation of exhaust gas and for flame stabilization. The in operation material temperature, temperature changes and atmospheres at the flame tube have been measured. Exposure tests of four Ni-Cr-alloys with different concentrations of Al have been carried out under these conditions. The breakdown of the material was connected with the failure of the oxide layer and finally with the formation of internal aluminium nitrides. An approach has been developed for predicting the failure of the oxide layer and hence of the life time of the material. 相似文献
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变频器是主轴模拟控制的一个重要组成部分,通过分析变频器的作用及主要端子功能,研究了主轴模拟控制过程中,变频器与数控装置之间的正确连接方法。以一个典型故障为基础,阐述了其故障分析与诊断过程。 相似文献
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J. C. LaSalvia J. Campbell J. J. Swab J. W. McCauley 《JOM Journal of the Minerals, Metals and Materials Society》2010,62(1):16-23
Because of their lightweight and high hardness, ceramics have been successfully used in protection technologies for over 40
years. The high hardness of a ceramic enables it to break, fragment, and deform impacting projectiles. This paper deals with
a number of issues connected to the application of ceramics to ballistic protection, including ceramic hardness, inelastic
deformation mechanisms, basic ballistic phenomenology and experimentation, ceramic damage due to ballistic impact, performance/failure
maps based upon specific damage/failure mechanisms, and what possible future types of ceramics the suppression of these damage/failure
mechanisms guide us to. 相似文献
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In-Hwan Shin Jae-Mean Koo Chang-Sung Seok Sung-Ho Yang Tack-Woon Lee Bum-Soo Kim 《Surface & coatings technology》2011
Plasma-sprayed thermal barrier coatings (TBCs) are applied to protect the blades of a gas turbine system from high-temperature gas and to lower the surface temperature of the blades. The failure of TBC is directly connected to the failure of the blades because the spallation of a ceramic layer leads to the acceleration of local corrosion and oxidation at the location of failure. Therefore, the spallation life of TBC is very important in the evaluation of the reliability of a gas-turbine blade.In this study, thermal fatigue tests were performed at 1100 °C and 1151 °C. Then, c-scanning and bond strength tests were performed for TBC specimens that were thermally aged by thermal fatigue tests. From the results, an empirical equation based on the ratio of the delamination area and the thermal cycle number was presented and the spallation life of a TBC specimen could be roughly estimated using the relationship between the delaminated area and the number of cycles. 相似文献