双向旋转技术在接插件端子级进模中的应用

分析了某接插件端子零件的成形工艺特点,首次应用一种新的冲压技术(双向旋转技术)优化了传统的成形工艺,并介绍了利用该工艺时,其级进模的排样设计、模具结构及工作过程.新工艺通过改善产品设计避免使用"二次成形",从而达到降低成本、缩短周期之目的,同时也为适应接插件端子的"轻、薄、短、小"发展趋势开阔了新思路.     

汽车端子多工位级进模设计

分析了汽车端子零件的冲压工艺,介绍了排样设计、模具结构特点及关键零件设计。着重介绍了汽车端子零件与配套插头及塑料护套接触部位的舌部和方框的成形方法,同时,采取相应的成形结构,既保证了零件顺利成形又使其本身结构简单便于加工,并可根据试模情况及时更改成形部位尺寸。模具现已投入生产,零件质量符合图纸要求,对同类零件的模具设计有一定的借鉴作用。     

B形插座端子多工位级进模设计

分析了B形插座端子制件的冲压成形工艺,阐述了采用级进模生产的可行性,介绍了成形制件所具有的冲孔、打印、切边、倒角、打字打凸、折弯、切舌、成形、整形等15个工位的排样设计,以及模具结构特点和关键制件的设计;插座端子的B形弯曲时,经多次弯曲后成形应力大回弹难以控制,着重论述了分步进行,逐渐成形,减少回弹进行B形弯曲成形的方法。模具投入生产后证明:结构合理,正常高效,制件质量稳定符合图纸要求。     

插座端子级进模设计

通过对一款插座端子的双排设计，分析了接插件端子零件的冲压工艺，阐述了采用多工位级进模生产的可能性，介绍了该产品的双排排样设计、关键零件设计、模具结构特点。     

提高转接段外套成形质量的优化成形工艺

从缩口成形过程中传力区的受力状态、缩口成形模具的结构缺陷及零件成形回弹等方面分析了某燃气轮机燃烧室转接段外套缩口成形后直径尺寸超差的原因,证实了缩口工艺不适合该零件成形加工.讨论了用胀形工艺取代原来的缩口工艺,使零件在成形过程中受拉应力作用,进行整体胀形,克服了缩口成形过程中压应力使零件变形区壁厚增厚、传力区失稳等问题.同时,胀形模具采用锥形滑块机构的分块式刚性凸模,通过胀形试验确定了凸模的型面尺寸,实现了零件成形回弹的工艺补偿,提高了零件成形质量.     

接插件端子多工位级进模设计

对一副接插件端子的多工位级进模设计过程进行了介绍，重点阐述了模具工作时各成形动作的协调性，给出了此类模具的规范结构、凸凹模镶块的型式及计算机辅助设计的体会。     

汽车连接器端子冲压工艺与模具设计

分析了汽车连接器端子的工艺,连接器端子体型小,精度高,结构复杂,为此设计了一副多工位级进模,重点介绍了端子弯曲成形和对弯曲回弹的矫正。模具经生产实践,零件符合设计要求,可供同类零件设计参考。     

弯形舌头插座端子高速级进模设计

通过对一款汽车用插座端子的模具设计,分析了接插件端子零件的结构及冲压工艺的难点,介绍了成形该产品的排样、关键零件、模具结构等的设计,重点论述了产品内部弯形舌头的设计。生产实践证明：该模具结构设计合理可靠,工作效率高,产品质量稳定,对同类产品的模具设计具有一定的参考价值。     

接插件端子多工位级进模设计

介绍了接插件端子多工位级进模设计，重点阐述了模具工作时各成形动作的协调性，给出了此类模具的规范结构，以及凸、凹模镶块的形式，并介绍了计算机辅助模具设计的体会。     

盒形件拉深成形工艺的数值模拟

采用有限元分析软件对盒形件拉深成形过程进行模拟,研究了盒形件成形过程中的回弹问题及盒形件厚度变化规律.对零件不合适的部位进行工艺调整,确定合理的拉深形状,避免在模具制造完成后造成大量的修模.研究结果表明:修改后的零件,拉深成形后其回弹值较小,完全能满足设计要求.并且,盒形零件修改后的厚度变化更趋均匀,受力更合理,特别是凹模受力,其加载曲线接近线性.减少了对模具的冲击,有利于延长模具的寿命.     

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.     

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 80m, 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.     

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.     

STUDY ON PROPERTIES OF PULSE ELECTRODEPOSITED RE-Ni-W-P-SiC COMPOSITE COATINGS

The effects of pulse frequency f and duty cycle r on the deposition rate, composition, morphology, and hardness of pulse electrodeposited RE （rare earth）-Ni-W-P-SiC composite coatings have been studied. The results indicate that pulse current can improve the deposition rate of RE-Ni-W-P-SiC composite coatings; W, P, and SiC contents in the coating decrease with the increase of pulse frequency and reach the lowest value at f = 33Hz, whereas the RE content in the composite coatings increases with the increase of pulse frequency. SiC content decreases with the increase of duty cycle, W content reaches the lowest value, and P content reaches the highest value at r = 0.4; pulse current and RE can lead to smaller size of the crystalline grains; however, the effects of different pulse frequency and duty cycle on the morphologies of RE-Ni-W-P-SiC composite coatings are not obvious. The hardness of RE-Ni-W-P-SiC composite coatings is the highest when the duty cycle is at 0.6 and 0.8 and pulse frequency is at 50Hz. At the same pulse frequency, the hardness of RE-Ni-W-P-SiC composite coatings at r= 0.8 is higher than that at r= 0.6.     

RELATIONSHIP BETWEEN J-INTEGRAL AND FRACTURE SURFACE AVERAGE PROFILE

To investigate the causes that led to the formation of cracks in materials, a novel method that only considered the fracture surfaces for determining the fracture toughness parameters of J-integral for plain strain was proposed The principle of the fracture-surface topography analysis （FRASTA） was used. In FRASTA, the fracture surfaces were scanned by laser microscope and the elevation data was recorded for analysis. The relationship between J-integral and fracture surface average profile for plain strain was deduced. It was also verified that the J-integral determined by the novel method and by the compliance method matches each other well.