感应加热在锡焊上的应用

感应加热具有加热速度快、效率高、易实现自动化的特点，万其在锡焊方面。由于焊锡熔点低，效果更加明显。在感应钎焊中，感应卷的设计是关键。     

领先的感应加热热处理设备

在过去的二十年中，感应处理的应用已越来越广泛。其主要原因之一是由于对工件进行热处理时，感应加人有只对需要轴热区域精确地进行集中、快速加热这一能力，从而缩短了处理时间，因此在满足技术要求的同时，提高了生产率。感应加热与大部分其它用于热处理的热源相比，提高了能源效率，同时对环境无害。本文是关于感应加热在现代金属热处理领域所取得综述，具体涉及齿轮感应淬火、在线回火、凸轮轴承面淬火、品质保证、过程控制／临     

国外汽车工业感应热处理技术的发展与应用

感应热处理在国外应用十分广泛。感应热处理零件所占比重在逐渐扩大。感应热处理设备制造水平越来越高，品种越来越多，感应热处理新工艺、新材料不断涌现。1低淬钢种类、特点1．五种类问）低碳低淬钢，其含碳量为0．2％，适用于汽车车架。（2）中碳低淬钢，含碳量为0．4％～0．6％，适用于轴类、齿轮和钢板弹簧。（）高碳低淬钢，含碳量为0·95％～l·05％，适用于轴承。l·2低淬钢特点（l）钢中合金含量低，因此淬透性低；（2）本质细晶粒，感应加热淬火，晶粒度可达11～12级；（3）淬火时需要很大的临界冷速，表面冷速8000～30000℃／S…     

0.5吨铸铁用无芯工频感应电炉炉衬烘烤与烧结

我厂使用0.5t无芯工频感应电炉,在没有调压装置情况下,我们采用“空炉断续通电、缓慢升温”烘烤炉衬。实践说明只要工艺制订合理。仍然可以达到预期的目的。下表是我厂对0.5t无芯工频感应电炉炉衬烘烤与烧结断续通电的时限工艺: 一、炉衬捣筑和炉盖筑砌好后,立即取出压铁,清除钢坩埚内的石英砂和其它杂物。然后将电路、冷却水路检查后进行试运行,若无问题,方可通电烘炉。200℃以前要求断续通电、缓慢     

感应熔炼电炉的技术规格及炉型选择

以实践经验为基础,对感应熔炼电炉的炉膛容量、熔炼时间、比功率、谐振频率、补偿电容等主要技术规格及其相互间的关系,试用数学的方式作出表述;对工频感应电炉、中频感应电炉、中频变频感应电炉等主要炉型,试用基本原理图作出解析,以期对感应熔炼电炉的主要技术规格及其炉型的选择提供参考.     

欧洲的感应淬火和感应加热

一、引言和历史背景欧洲感应淬火的发展是建立在特有的技术和经济条件上的,劳动力就是一个经济条件。本世纪60年代,由于缺少劳动力,约有300万外籍工人进入联邦德国;其他欧洲国家也雇佣外籍工人。此外,作为感应淬火设备主要用户的汽车工业,受到的冲击并不太     

轧机用感应加热器的国产化

我公司从英国进口的预热、加热两套感应加热器用于变截面弹簧轧制前加热的。感应器为浇铸全封闭悬臂式结构,经多年使用后发现故障率高,维修费用大,周期长,直接影响变截面弹簧生产。为此我们自行研制了新的感应器,满足了工艺要求,现已推广应用。１感应加热技术要求所...     

高频感应电热设备常见故障诊断及处理

用于工业热处理或冶金熔炼的高频感应电热设备，常因工作在高频高压状态以及大电流动态变量的过渡过程中，因而这类设备在实际应用中不仅对使用条件的要求较高（例如供水供电的质量要求以及环境的温度与湿度要求等），而且对设备运行中的过渡过程的适时比例控制要求也较严格。倘若设备在使用过程中，或因使用条件的不满足，或因操作比例失调以及维修保养不当等原因影响，极易引发设备的各类故障。事实表明，这些故障的易发部位及故障维修的难点大都在设备的高频与高压系统电路内。为提高诊断速度与维修效率，笔者根据多年来的使用维修经验，…     

导磁体在汽车零件感应加热中的应用技术

本文简单介绍了导磁体工作的基本原理，并给出在汽车零件大规模生产中所积累的导磁体应用的一些经验，以阐明如何更有效地使用导磁体。     

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.     

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.     

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.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.