闪光对焊参数微机测判装置

本文研制了由单片机的闪光对焊参数测试及质量判定装置。本装置通过采集对焊过程的位移，电流和油压等数据，再经过数据处理，能够打印输出闪光留量，闪光速度、顶锻留量，有电要面锻留量、顶锻速度及顶锻压强等参数，并能判上述参数合理与否，如果需要还能打印出过程的焊接电流与位移的变化曲线。     

铝铜异种材料线性摩擦焊接头的微观组织与力学性能

采用不同的顶锻力对AA5083-H112铝合金和T2纯铜进行了线性摩擦焊接,获得了无明显缺陷的焊接头,并通过扫描电镜、硬度、力学性能试验等方法研究了线性摩擦焊铝铜接头的微观组织和力学性能。结果表明,随着顶锻力的减小,摩擦效应增加,更多的铜颗粒渗入铝基体中;而随着顶锻力的增加,拉伸力学性能明显下降,这是由于较大的顶锻力会使摩擦过程的热输入量增大,从而在铝铜结合处生成层状的第二相Al_2CuMg,使焊接头的力学性能降低。     

连续驱动摩擦焊接45钢过程温度与材料流动的3D数值模拟

以45钢为对象,研究了连续驱动摩擦焊过程的温度场以及材料流动的位移场。数值模拟结果表明,在连续驱动焊过程的摩擦阶段,摩擦界面及其附近的材料温度值逐渐增加,材料向试件外流动的位移也随之增加;在停止阶段,试件的温度峰值降低,而材料流动的位移量在大轴向压力的作用下大幅度升高;在顶锻阶段,随着界面温度值的继续降低,使材料的流动位移缓慢增加并趋向稳定。     

高能离合器螺旋压力机力能关系研究

本文应用能量理论导出了高能离合器式螺旋压力机打击过程中离合器脱开力、锻件变形能及锻击终锻力三个重要参量之间相互关系数学表达式;绘出了离合器脱开力与锻击终锻力关系曲线图及锻件变形能与锻击终锻力曲线图。为压力机力能参景控制、调节及惯性控制系统的设计提供了重要的理论依据。     

大型曲轴镦锻过程中材料的变形抗力分析

介绍了大型曲轴镦锻成形的特点,建立了坯料和模具的CAD装配模型；应用CAE数值模拟技术对曲轴的镦锻过程做了分析,得到了曲柄成形的位移场、主要模具的应力场和载荷曲线图,得到了材料的最大变形抗力,即最大的镦锻力；最后分析了变形抗力对模具磨损的影响.     

顶锻刹车制度对摩擦焊接后峰值扭矩的影响

研究了顶锻刹车制度和顶锻超前刹车时间对摩擦焊接后峰值扭矩和顶锻变形量的影响。发现采用顶锻超前刹车模式会导致较大的后峰值扭矩和顶锻变形量，而且随着顶锻超前刹车时间的延长，在试验范围内，后峰值扭矩和顶锻变形量不有所增加，而采用顶锻同步或顶锻滞后刹车制度时，均不存在后峰值扭矩，相应顶为形较小。     

LFW系统顶锻方向位置与压力转换无扰控制原理的分析及试验

为改进线性摩擦焊接系统中所设计的顶锻方向液压控制位置和压力转换控制过程,提高顶锻方向位置精度,对其液压控制位置和压力转换控制方式的原理进行研究,明确顶锻方向位置控制和压力控制的特点及其各自应采用的控制器的形式.进一步研究顶锻方向位置控制和压力转换控制策略,提出顶锻位置控制和压力协同控制方法,对控制特性进行试验验证.研究结果对提高主机的生产效率和性能具有理论和实际意义.     

工业纯钛摩擦螺柱焊接头组织与性能研究

为解决传统电弧螺柱焊焊接大直径（M≥12 mm）有色金属时焊缝合格率低、焊接工艺繁琐等问题,提出采用静龙门式搅拌摩擦焊设备配合专用螺柱焊工装对尺寸为M12、材质为TA2的工业纯钛螺柱与底板进行焊接。并对三组不同顶锻位移下的工业纯钛螺柱焊接头进行宏观形貌、显微组织、抗扭强度与显微硬度分析。结果表明,在顶锻位移较小的情况下,TA2螺柱焊接头焊缝中心出现孔洞缺陷,顶锻位移中等的情况下焊缝中心出现条状缺陷,而较大参数下接头焊合良好,未发现缺陷;顶锻位移为3 mm时接头抗扭强度最高,可达117 N·m;锻造变形组织使焊缝附近区域显微硬度明显升高。     

基于PLC控制的汽车轮圈闪光顶锻焊机设计

介绍了应用在某车轮厂的汽车轮圈闪光顶锻焊机的液压传动与控制系统的设计，该系统利用可编程控制器控制的电液比例方向阀来对顶锻焊机闪光阶段进行精确的控制，使工件的位移曲线和闪光曲线一致。设计制造的系统现场应用效果良好。     

K系列固定焊机顶锻系统改造及顶锻工艺

顶锻是钢轨闪光焊接的关键阶段,K系列焊机具有加热宽度窄、加热温度场陡等特点,但顶锻力和顶锻速度等顶锻性能参数相比于GAAS80类固定焊机有所欠缺,从K1000固定式焊机顶锻控制程序和顶锻油路结构两个方面进行改造,以提高顶锻速度和保压能力,提高带电顶锻阶段功能为目的。结果表明:经过硬件方面的调整和优化,满足了顶锻工艺参数的调整范围,提高了钢轨焊头质量,特别针对U75V类钢轨和耐蚀轨等高合金钢种,有着积极的效果。     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

The 15th Global Foundry Sourcing Conference 2014held in Qingdao China

Organized by Suppliers China Co., Ltd and co-organized by the National Technical Committee 54 on Foundry of Standardization Administration of China, the 15th Global Foundry Sourcing Conference 2014 （hereinafter referred to as FSC 2014） was successfully held on Sep. 23rd in Grand Regency Hotel, Qingdao. More than 500 delegates from home and abroad attended this conference, including over 130 purchasers from 20 countries and 380 domestic and foreign suppliers.     

Secondary Recrystallization Behaviors of Grain-Oriented 6.5 wt% Silicon Steel Sheets Produced by Rolling and Nitriding Processes

By rolling and nitriding processes, 0.23- to 0.3-mm-thick grain-oriented 6.5 wt% silicon steel sheets were produced. The core losses of grain-oriented 6.5 wt% silicon steel at frequencies ranging from 400 Hz to 20 k Hz were lower than that of the grain-oriented 3 wt% silicon steel with the same thickness by 16.6–35.8%. The secondary recrystallization behavior was investigated by scanning electron microscopy, energy-dispersive spectroscopy, and electron backscattered diffraction. The results show that the secondary recrystallization in high-silicon steel sheets develops more completely as the nitrogen content increases after nitriding, secondary recrystallized grain sizes become larger, and the sharpness of Goss texture increases. Because more {110}116 grains in the subsurface and the central layer of the sheets have a lot of 20°–45° high-energy boundaries in addition to Goss grains, {110}116 can be the main component through selective growth during secondary recrystallization when the inhibitor quantity is not enough and inhibitor intensity is weaker. The increases in nitrogen content can increase the inhibitor intensity and hinder abnormal growth of a mount of {110}116 grains and therefore enhance the sharpness of Goss texture.     

Laser Cladded TiCN Coatings on the Surface of Titanium

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

Microstructure and Mechanical Properties of X80 Pipeline Steel Joints by Friction Stir Welding Under Various Cooling Conditions

X80 pipeline steel plates were friction stir welded(FSW) under air, water, liquid CO_2 + water, and liquid CO_2 cooling conditions, producing defect-free welds. The microstructural evolution and mechanical properties of these FSW joints were studied. Coarse granular bainite was observed in the nugget zone(NZ) under air cooling, and lath bainite and lath martensite increased signifi cantly as the cooling medium temperature reduced. In particular, under the liquid CO_2 cooling condition, a dual phase structure of lath martensite and fi ne ferrite appeared in the NZ. Compared to the case under air cooling, a strong shear texture was identifi ed in the NZs under other rapid cooling conditions, because the partial deformation at elevated temperature was retained through higher cooling rates. Under liquid CO_2 cooling, the highest transverse tensile strength and elongation of the joint reached 92% and 82% of those of the basal metal(BM), respectively, due to the weak tempering softening. A maximum impact energy of up to 93% of that of the BM was obtained in the NZ under liquid CO_2 cooling, which was attributed to the operation of the dual phase of lath martensite and fi ne ferrite.     

INDUSTRY NEWS

China Securities News reported on March 21, 2014： Guangdong Hongtu Wuhan Die Casting Co., Ltd. （Wuhan Hongtu）, a wholly owned subsidiary of Guangdong Hongtu Technology （Holdings） Co., Ltd., held a groundbreaking ceremony recently. With the registered capital of 50 million Yuan, Wuhan Hongtu has a total land area of 100,000 square meters and a plant construction area of 72,000 square meters. It is expected to have a production capacity of about 30,000 tonnes of aluminum castings annually after it is put into production.     

Microstructure,Mechanical Properties and Corrosion Behavior of Extruded Mg–Zn–Ag Alloys with Single-Phase Structure

Mg–Zn–Ag alloys have been extensively studied in recent years for potential biodegradable implants due to their unique mechanical properties,biodegradability and biocompatibility.In the present study,Mg–3Zn-x Ag(wt%,x=0.2,0.5 and0.8)alloys with single-phase crystal structure were prepared by backward extrusion at 340°C.The addition of Ag element into Mg–3Zn slightly influences the ultimate tensile strength and microstructure,but the elongation firstly increases from12%to 19.8%and then decreases from 19.8%to 9.9%with the increment of Ag concentration.The tensile yield strength,ultimate tensile strength and elongation of Mg–3Zn–0.2Ag alloy reach up to 142,234 MPa and 19.8%,respectively,which are the best mechanical performance of Mg–Zn–Ag alloys in the present work.The extruded Mg–3Zn–0.2Ag alloy also possesses the best corrosion behavior with the corresponding corrosion rate of 3.2 mm/year in immersion test,which could be explained by the single-phase and uniformly distributed grain structure,and the fewer twinning.     

Growth Morphologies of a Binary Alloy with Low Anisotropy in Directional Solidification

Two new classes of growth morphologies, called doublons and seaweed, were simulated using a phase-field method. The evolution of doublon and seaweed morphologies was obtained in directional solidification. The influence of orientation and velocity on the growth morphology was investigated. It was indicated that doublons preferred growing with its crystallographic axis aligned with the heat flow direction. Seaweed, on the other hand, could be obtained by tilting the crystalline axis to 45°. Stable doublons could only exist in a range of velocity regime. Beyond this regime the patterns formed would be unstable. The simulation results agreed with the reported experimental results qualitatively.