工程油缸活塞杆摩擦焊接工艺优化研究

对材料为45钢、直径为?48的工程油缸活塞杆摩擦焊接技术进行了系统深入的研究，从工程油缸活塞杆焊接结构、热处理时机和摩擦焊接工艺规范3个方面因素，对活塞杆摩擦焊接接头综合性能的影响进行了研究。通过试验研究揭示了摩擦焊接各因素与焊接接头可靠性的关系，初步建立了活塞杆摩擦焊接成型与控制的工程体系。制订了活塞杆接头可靠性所需的工艺规范，使活塞杆摩擦焊接接头的抗拉强度达到800 MPa以上，屈服强度达到500 MPa以上，断面收缩率达到35%以上，满足了工程液压缸的技术要求。验证了优化后摩擦焊接工艺规范加工成型的焊接接头可靠性，优化后焊接接头合格率达到99.99%以上。     

摩擦焊工艺在刀具制作中的应用

摩擦焊是以两零件的焊接面在相互压紧的条件下做任何轨迹的相对运动,产生的摩擦热作为热源把焊件的焊接面加热到塑性状态,然后顶锻形成焊接接头的工艺方法。常用金属材料摩擦焊的焊接性如下表所示。由于摩擦焊技术可焊接的金属范围广,特别适于焊接异种金属,具有焊接接头质量高、焊接尺寸和几何精度高、节能、节材以及高效等优点,已经广泛地在机械制造零部件中得到应用,但用于刀具制造领域则较少。本文通过对刀杆进行摩擦焊工艺试验,验证了摩擦焊用于刀具制作的可行性。     

摩擦焊工艺特点及技术参数的调节

摩擦焊较之闪光焊虽然不要求对管端外壁进行清理,但由于摩擦时间短、烧化量小,因而管子端面的粗糙度、不平度和垂直度对焊接质量影响很大,所以对管端制备的要求较高,只有管端平整而垂直,才能使摩擦过程中,热力沿径向、轴向和元周分布均匀,顶锻时变形一致,接头质量优良。一、摩擦与进给摩擦焊是热压焊的一种,焊接质量主要取决于加热与加压和摩擦过程,即是焊接接头的加热过程。在摩擦过程中,升温速度与热力的分布,主要取     

5A05铝合金薄板搅拌摩擦焊装配因素对焊缝质量的影响

文中通过5A05铝合金薄板搅拌摩擦焊对接试验,进行了力学性能分析和X射线探伤,研究接头错边量和间隙量对搅拌摩擦焊对接接头缺陷和力学性能的影响。试验结果表明当错边量大于0.5 mm或间隙量大于0.8 mm时焊缝力学性能下降并伴随下压量增大和缺陷的产生,接头缺陷与拉伸试验断裂部位大多在焊缝前进侧。错边量和间隙量对铝合金薄板搅拌摩擦焊对接接头力学性能及内部质量有重要影响,为保证焊接生产质量,搅拌摩擦焊焊接过程中应该严格控制接头错边量和间隙量。     

GPW-1200Ⅱ型集装箱式气压焊大准重载铁路线上焊的应用与研究

本文通过GPW—1200Ⅱ型集装箱式气压焊设备在大准重载铁路上的实际施工及应用,研究大型气压焊在75kg/m钢轨重载铁路线路带应力线上焊和不带应力线上焊的可行性和施工方法。结果表明:GPW—1200Ⅱ型集装箱式气压焊设备,能够满足重载铁路75kg/m钢轨一次换铺、放散、线上焊的施工要求和焊接接头质量要求;在一个天窗作业时间内,可完成一对75kg/m钢轨线上接头焊接,满足现场施工时间要求;根据现场实际使用情况,GPW—1200气压焊轨机至少能够满足现场锁定轨温差小于10℃的75kg/m钢轨线上应力焊焊接质量要求,确保了焊接区锁定轨温满足线路锁定轨温要求;从型式检验结果及焊接接头使用情况表明其焊接接头质量优良,平直度良好,能够满足大准线重载无缝线路的运营要求。     

大型挖掘机活塞杆窄间隙MAG焊工艺研究

该文首先对窄间隙MAG焊设备组成进行了介绍,并将其用于挖掘机液压缸活塞杆焊接;然后根据NB/T47014-2011标准对焊接接头拉伸强度、弯曲性能、冲击韧性、金相组织及硬度分布进行了表征,结果表明接头的焊态冶金质量符合国家标准要求;最后分析了窄间隙MAG焊在深坡口(≥50 mm)焊接方面的经济优势,指出其焊接效率较传统MAG焊可提高50%以上,而焊材消耗可以减少40%以上。     

2219铝合金搅拌摩擦焊工艺及接头性能

采用搅拌摩擦焊方法对6 mm厚的2219铝合金板进行焊接,研究了2219铝合金的搅拌摩擦焊工艺和主要焊接参数对焊缝成形和接头力学性能的影响.结果表明:在旋转速度1250～1400 r·min-1,焊接速度100～140 mm·min-1时,可获得性能良好的焊接接头;对2219铝合金搅拌摩擦焊接后再固溶时效处理可有效消除接头软化区,提高接头强度.     

中厚板高强钢Q460C高效气保焊工艺实验研究

采用高效气保焊工艺,可以提高中厚板高强钢Q460C的焊接性能.因此,通过实验对该工艺过程进行研究.研究结果表明:通过采用双丝双弧气保焊大熔深工艺来增加熔深,解决了根部熔合质量问题,同时在不开坡口的形式下获得了更高的焊接速度;焊后焊接接头的抗拉强度达到825 MPa,断裂位置发生在母材上,焊接接头的硬度及冲击功力学性能指标均满足标准要求.     

搅拌摩擦焊返工工艺研究

介绍了搅拌摩擦焊在轨道交通车辆侧墙制造应用中出现的平面度超差、焊接缺陷等质量问题,通过对侧墙板搅拌摩擦焊焊缝使用搅拌摩擦焊调平、弧焊补焊、重复焊接等方法进行返工,对返工后的接头进行宏观试验、拉伸试验和弯曲试验,并根据ISO25239对试验结果进行评判,最终确定对存在缺陷的搅拌摩擦焊焊缝进行返工的可行性。     

几种零件的摩擦焊接工艺

摩擦焊接是一种先进的焊接工艺,近几年来这种工艺方法在我国逐步得到推广应用。许多用户进行了焊接工艺和焊接接头的机械性能试验,取得了满意的结果。摩擦焊工艺具有①接头强度等于或高于母材;②节省电能;③省材料;④废品率低;⑨提高生产率和机械化程度;⑥减轻劳动强度,无废烟、废气,不污染环境等优点。经过焊接工艺试验,对摩擦焊质量更加信服,进一步促进了摩擦焊工艺的推广应用。摩擦焊适宜于具有圆形截面的零件,如棒料和棒     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...