铝轴自动化探伤与分拣控制系统的设计

为了克服铝轴手动探伤与分拣效率低、可靠性不高和劳动强度大的不足,设计了铝轴自动化探伤与分拣控制系统,对该系统的机械结构、硬件组成和软件流程进行了详细地描述。该系统是基于工控机和PLC相结合的方式,工控机作为上位机完成包括人机交互和数据采集与分析等工作,PLC实现探伤过程的自动控制。待检铝轴经辊道传送至探伤区,被逐个探伤并根据是否有缺陷在出料区进行分拣,所设计的系统可以提高铝轴探伤与分拣的可靠性和效率并大大减轻劳动强度。

钛铝涡轮轴与K418合金轴套过盈配合内应力分析

通过有限元ABAQUS软件对钛铝涡轮轴与K418合金轴套的过盈配合进行了详细研究,分别从过盈量、连接件几何结构和装配长度等因素入手,分析了压装过程中应力的变化情况,指出应力最大的位置,从理论上提出降低应力和提高寿命的措施。比较钛铝涡轮轴与K418合金轴套不同过盈量下及不同接触长度下过盈配合装配的应力分布结果,表明过盈量是影响装配应力的主要因素,得出较合理的过盈量应在0.15 mm左右,装配接触长度对装配应力也有一定影响。通过不同过渡圆角的模拟计算发现过渡圆角的大小对应力的影响较大,与压装过程中出现的应力峰值有直接的关系。所以在设计时可以采取在合适的范围内增大过渡圆角或添加去应力槽的方式减小应力集中现象,从而降低装配过程中出现的应力峰值,减少对涡轮轴材料的损伤。

点火黑腔用铝铜复合芯轴的制备及性能

选取纯度较高的1100铝棒作为加工模芯的原材料,利用金刚石车床精加工出表面粗糙度均方根值小于20nm的铝模芯,采用磁控溅射的方法在铝模芯上制备厚度大于5μm的铜防护层,得到铝铜复合芯轴。对制备的铜防护层的表面微观结构、结晶性能、厚度一致性进行了分析测试,结果表明磁控溅射法制备的铜防护层沿(111)面择优生长,表面粗糙度均方根值小于30nm,厚度一致性优于95%,圆柱度小于1μm。镀层与基底结合力强,可满足大厚度黑腔涂层的制备需求。

国产703高强铝合金轴压角铝构件试验

完成了703铝合金材料的拉伸试验,得到其力学性能和本构关系。对24根国产703高强轴压角铝构件进行了承载力试验,得到该类构件在轴压作用下的极限承载力和破坏模式。建立了数值分析模型,通过试验结果和数值分析结果的对比,验证了数值模型的正确性。完成大量数值分析,分析了构件长细比和截面规格等因素对构件承载力的影响规律。最后,对比了我国规范公式计算得到的稳定系数和试验实测的稳定系数。结果表明,我国《铝合金结构设计规范:GB 50429—2007》能有效计算国产703高强轴压角铝构件的整体稳定承载力。

内孔含自润滑材料轴套控制内径尺寸的工装设计

某内孔含自润滑材料的轴套,内径尺寸公差要求较高,但无法通过机加工进行控制。基体材料是采用轴承钢,自润滑材料则是具有一定弹性的热固性材料。在一定的温度和压力下,自润滑材料会硬化。该文通过不同材料热膨胀系数不同的原理,进行相关的设计与计算,设计能够控制内径尺寸的芯轴工装和工艺方案。选择工装材料,调整工艺参数进行试验。在特定的基体材料尺寸、芯轴材料尺寸、温度和压力下,可以调整自润滑材料的硬化结果,进而控制轴套含自润滑材料的内径尺寸,以满足设计精度要求。

Role of inclination angle on columnar-to-equiaxed transition in the eutectic Al-5Mg-2Si alloy fabricated by laser powder bed fusion

In this study,the effect of inclination angles relative to the building direction in the additively manufactured eutectic Al-5Mg-2Si alloy was investigated through the laser powder bed fusion(LPBF).The microstructures and mechanical properties of the Al-5Mg-2Si alloy manufactured with different inclination angles(0°,30°,45°,60°and 90°)were reported and discussed.It is found that the“semicircular”melt pool(MP)in the load bearing face of 0°sample was eventually transformed into“stripe-like”MP in the 90°sample,accompanied by an increased fraction of melt pool boundaries(MPBs).Moreover,the microstructural analysis revealed that the columnar-to-equiaxed transition(CET)of theα-Al grains and eutectic Mg2Si was completed in the 90°sample,which were significantly refined with the average size of 10.6μm and 0.44μm,respectively.It is also found that the 90°sample exhibited good combination of strength and elongation(i.e.yield strength of 393 MPa,ultimate tensile strength of 483 MPa and elongation of 8.1%).The anisotropic mechanical properties were highly associated with the refined microstructures,thermal stress,and density of MPBs.Additionally,the CET driven by inclination angles was attributed to the variation of thermal conditions inside the local MPs.

子米气田发电机水泵改造及效果评价

天然气生产的连续性要求集气站生产监控设备、井口注醇泵必须处于连续运转状态，因此集气站需要自备发电机使用，子米气田集气站使用KOHLER35RZG型发电机，该型发电机水泵在使用过程中出现铝轴松动，风扇叶片打坏的状况，子米气田经过屡次探索对该型水泵进行了技术改造，本文对技术改造进行了进一步的探讨。

Effect of carrier and axial ligand on the photocatalytic activity of cobalt thioporphyrazine

The photocatalytic activity of cobalt octakis（butylthio） porphyrazine（CoPz（BuS）8） was assessed through photodegradation of the dye rhodamine B（RhB） in water under irradiation with a Xe lamp and aerated conditions.The photocatalytic activity of CoPz（BuS）8 loaded on Al2O3 or SiO2@Fe3O4nanoparticles or coordinated with an axial azide ligand was also investigated.The results demonstrated that the photocatalytic activity of CoPz（BuS）8 loaded on Al2O3 was higher than that loaded on SiO2@Fe3O4.The kinetic curves of RhB degradation in aqueous solutions at different pH indicated the pseudo first-order kinetics of the reaction.The highest degradation rate for CoPz（BuS）8 loaded Al2O3 at pH = 4 after 160 min was 84.6%.However,the advantages of easier separation and recycling as well as the ability to terminate the reaction at any time for the CoPz（BuS）8 loaded SiO2@Fe3O4 cannot be ignored.When electron-rich NaN3 was coordinated with CoPz（BuS）8 as an axial ligand and loaded on Al2O3,the resulting catalyst produced more active oxygen species such as O2^- and HO· to promote the quicker degradation of RhB than that by the other catalysts.For the N3-coordinated CoPz（BuS）8 loaded on Al2O3,the reactions at pH = 4 and 7 distinctly deviated from first-order kinetics,and the degradation rate reached 77.6%after 80 min at pH = 4.

Fatigue Crack Initiation and Propagation of Aluminum Alloy Bearings

Observation of fatigue crack initiation and propagation during fatigue test in ALSn20Cu bearing has been presented. Journal center orbit, oil film pressure and stress distribution in alloy layer have been calculated and are taken as the basis for theoretically simulating the bearing fatigue process. It is found that the calculated results are in good accordance with the experimental results, which provides a feasible way for investigation of fatigue crack propagation process in the bearing.

Biaxial mechanical behavior of closed-cell aluminum foam under combined shear-compression loading

Combined shear-compression tests and simulations were performed on a closed-cell aluminum foam over a wide range of loading angles in order to probe their yield behaviors under biaxial loading conditions.Combined shear-compression tests were carried out by using a pair of cylindrical bars with beveled ends.The yield surfaces were experimentally measured and compared with various theoretical yield surface models.The cellular structures of closed-cell aluminum foams were modeled as tetrakaidecahedrons and their biaxial crushing behaviors were simulated by the finite element method.The results show that,yield initiates from the stress-concentrated corners in the specimens under combined shear-compression loading and the stress distribution is no longer uniform at the specimen/bar interfaces.In the range of cell sizes studied,the larger the foam cell size is,the higher the yield stress is.Aluminum foam density is found to be the dominant factor on its mechanical properties compared with the cell size and is much more significant in engineering practice.

Development of an automatic polishing system for aluminum wheel-hub surface

To improve polishing quality and cope with the shortage of skilled workers for aluminum wheel-hub surface polishing, an automatic surface polishing system with hierarchical control based on the teaching-playback method was presented. Multi-axis cutter location data (CL data) were generated with the teaching method. First, a helical tool path and a flexible polishing tool were adopted to achieve high quality and high efficiency; next, the initial irregular data were processed into continuous polishing CL data. The important factor affecting polishing quality, namely the interpolation cycle in the multi-axis CL data was calculated based on a constant removal rate. Results from polishing experiments show that the quality of automatic machine polishing is better and stabler than manual polishing.

Deformation division of metal flow behavior during extrusion process of 7075 aluminum alloy

To reduce defects caused by non-homogeneous metal flow in conventional extrusion,a die with guiding angle was designed to improve the metal flow behavior. The characteristic quantities such as the second invariant of the deviator stress J2 and Lode's coefficient μ were employed for the division of deformation area. The results show that when the metal is extruded with the guiding angle,no metal flow interface forms at the container's bottom,the dead zone completely disappears,the deformation types of the metal in the plastic deformation area change from three types to one type of tension,and the homogeneity of the deformation as well as metal flow are greatly improved. The non-homogeneous metal flow at the final stage of extrusion is improved,reducing the shrinkage hole at the axis end. The radial stress of the furthest point from the axis is transformed from tensile stress to compressive stress and the axial stress,and decreased from 70.8 to 34.8 MPa. Therefore,the surface cracks caused by additional stress are greatly reduced.

Fatigue damage rule of LY12CZ aluminium alloy under sequential biaxial loading

A series of biaxial two-level variable amplitude loading tests are conducted on smooth tubular specimens of LY12CZ alumin- ium alloy. The loading paths of 90° out-of-phase, 45° out-of-phase and 45° in-phase are utilized. The fatigue damage cumulative rules under two-level step loading of three loading paths are analyzed. By introducing a parameter a which is a function of the phase lag angle between the axial and the torsional loading, a new multiaxial nonlinear fatigue damage cumulative model is proposed. The proposed model is evaluated by the experimental aluminium alloy, and multi-level loading of 45 steel. Fatigue lives data for two-level loading, multi-level loading of LY12CZ predicted are within a factor of 2 scatter band.