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Meng X.W.,Zhuzhou Cemented Carbide Group Corporation Ltd.
Advanced Materials Research | Year: 2014

A new kind of binder was developed in extrusion molding. It included four ingredients:ethylene glycol acetate (60%~85% (mass/mass, as follows)), ethyl cellulose (10%~30%), ethylene glycol polyoxyethylene ether (5%~10%), polyethylene glycol stearate (0.8%~3%). The components of binder were compatible with thermodynamic conditions, so the binder was well-distributed in molecule level. The new binder is actual nontoxic, secure and environmentally friendly. The forming property of the binder is so excellent that it can load 54% ~ 56% (vol. /vol.) cemented carbidepowders. The rods produced by this new binder provide high strength, stable performance, homogeneous microstructure. © (2014) Trans Tech Publications, Switzerland. Source

Gu L.,Central South University | Huang J.,Central South University | Huang J.,Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education | Xie C.,Zhuzhou Cemented Carbide Group Corporation Ltd.
International Journal of Refractory Metals and Hard Materials | Year: 2014

Effects of carbon content on microstructure and properties of WC-20Co cemented carbides with carbon content from 4.45% to 5.25% prepared by sinter-HIP were analyzed by X-ray diffractometry (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), Rockwell hardness analysis, cobalt magnetic performance analysis, bending strength analysis and so on. The results show that carbon content plays a significant role in the phase composition and microstructure, WC grain size and shape, W solubility of the binder, and mechanical properties of cemented carbides. In the field of research, with increasing carbon content, the WC mean grain size increases and morphology characteristic of WC grains tends to show truncated trigonal prim shape. And carbon content also influences W solubility, so that in carbon-rich cemented carbides the binder dissolves about 4 mass% tungsten and in carbon-deficient cemented carbides up to 20 mass%. The density and Rockwell hardness of alloys decrease with increasing carbon content. On the contrary, the cobalt magnetic performance of alloys increases and the extent of variation gets smaller and smaller. The bending strength of alloys increases then substantially decreases with increasing carbon content and appears maximum in the two-phase region. © 2013 Elsevier Ltd. Source

Meng X.,Zhuzhou Cemented Carbide Group Corporation Ltd.
Advanced Materials Research | Year: 2011

The advantages and disadvantages between the pressing binder of hardmetal in existence are analyzed. A new type of binder named QSD is introduced and a series of properties are studied. The experiments show that QSD has been tested to dissolve in alcohol. The materials of hardmetal are milled in alcohol mixed with QSD, achieving a molecule dispersing slurry. The slurry adapts to spray drying with low viscidity. The mixture of the hardmetal prepared by QSD is fine, and soft with good flowability. They are capable of pressing complex form of products that couldn't be formed with PEG, paraffin wax binder by comparing the experiments. The compacting force has reduced 20% compared to PEG. The pressing products are effectively less vices of delamination and crack due to the low brittleness and high weight of compact. The products made by QSD fit continuous sintering and there are few remainder carbon in the sintered products. Microstructural observation reveals that the Co particle distributes homogeneously in the WC particle with the pressing binder QSD. So QSD is one kind of considerably ideal cemented carbide binder that combines the advantages of PEG, SBS. Source

Peng W.,State Key Laboratory of Cemented Carbide | Peng W.,Zhuzhou Cemented Carbide Group Corporation Ltd. | Kong D.,State Key Laboratory of Cemented Carbide | Kong D.,Zhuzhou Cemented Carbide Group Corporation Ltd.
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering | Year: 2016

The basic principle of synthesizing of gem-grade diamond using pressless "split sphere" high-pressure apparatus (BARS) was introduced. The property of cemented carbide anvils placed in BARS was presented, as well as the industrializing process of Chinese cemented carbide for BARS. Research showed that using WC-Co ultrafine composite powder after stirring ball milling, cold isostatic pressing and low pressure sintering would increase the uniformity of organizational structure, together with compressive strength and elastic modulus of hard alloy. The optimum project to machine self-localization anvil was to mutually act as reference and control product concentricity. Using M22/36 finishing wheel with a reasonable amount of feed in the grinding was the key to ensure the machining accuracy. © 2016, Zhengzhou Institute of Abrasives Grinding. All right reserved. Source

Wei X.,Central South University | Wei X.,Zhuzhou Cemented Carbide Group Corporation Ltd. | Zheng Z.,Central South University | She L.,Central South University | And 2 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2010

The effect of Mg and Zn additions on the microstructure evolution and mechanical properties of an Al-Cu-Li alloy was studied by transmission electron microscopy and tensile testing. Results show that additions of Mg and Zn can accelerate the precipitation of δ' phase nucleation and inhibit its growth, so the δ' phase becomes finer and more dispersive. In the under-aging condition, a lot of GP zones are formed in the alloy containing Mg and Zn. The alloy only containing Mg also has many GP zones. But no GP zone is found in the alloy only containing Zn, while only a few coarse θ' is found. The above results reveal that Mg promotes the formation of GP zones while the single role of Zn is not significant; Zn has a better effect when it acts with Mg together. As the aging proceeding, GP zones in the alloy containing Mg and Zn transforms into θ'/θ″ phase and plenty of θ'/θ″ phases are formed in the alloy only containing Mg, but θ' phase dose not change obviously in the alloy only containing Zn. It indicates that Mg is the key element to accelerate θ'/θ″ phase formation, and Zn can promote the formation only with Mg. Source

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