Antifriction surfacing of titanium alloys

A method for antifriction deposition of layers on titanium components is described. The hardness of deposited metal can be varied in a wide range and the method is easy to apply and has high economic parameters.     

Investigation of the processes of surfacing joint faces in turbine casings in nuclear power stations

Tests were carried out of the separation resistance of a chromium–nickel metal, deposited on carbon steels by different methods. Surfacing with simultaneous formation of a high austenite sublayer increases the separation resistance while saving a large amount of high-nickel alloy.     

The corrosion and oxidation resistance of iron- and aluminium-based powder metallurgical alloys

The corrosion performance of both iron- and aluminium-based powder metals is reviewed and compared, where possible, to similar conventional alloys. Iron-based alloys produced from consolidated powder or compacted amorphous chips have generally been found to have improved corrosion resistance compared to their wrought counterparts, whereas sintered iron-based alloys generally exhibit poorer corrosion resistance. The corrosion performance of aluminium-based alloys produced from consolidated powder is frequently better than that of their conventional counterparts. Aluminium alloys are considered in four groups: AlZnMgCu, AlMg, AlLi and AlCu alloys. The current understanding of the corrosion behaviour of powder metals is assessed and suggestions are made for future investigations.     

Q235基体上CMT-TWIN技术堆焊镍基合金

以Q235为基体,以镍基合金Inconel625(φ1.0 mm焊丝)为堆焊材料,采用CMT-TWIN焊接技术进行堆焊,试验结果表明最佳参数为:电弧电压14.7 V,焊接电流98 A,焊接速度4 mm/s,摆宽10 mm(双丝参数一致),能够获得致密美观、无缺陷的镍基合金堆焊层。从熔合线附近到堆焊层中心,组织为树枝晶形态的奥氏体;EDS表明元素含量在熔合线附近发生突变的区域较窄(10~20μm),而在堆焊层中分布较均匀,说明熔合比较小;剪切试验表明基体与堆焊层结合界面的抗剪强度大于326 MPa,断口形貌表明为韧性断裂。     

等离子弧堆焊TiC增强NiTi合金的组织和耐磨性

利用等离子弧堆焊方法在Q235钢板表面制备了添加TiC颗粒的NiTi合金耐磨堆焊层,并对堆焊层的微观组织和耐磨性进行研究.结果表明,在湿砂橡胶轮磨粒磨损试验条件下,当TiC加入量为55％时堆焊层的相对耐磨性最好,为Q235钢的11倍.TiC含量为55％的堆焊层由TiC、Ni3Ti及NiTi组成,堆焊层组织致密、与基材之间结合良好.堆焊层具有优异耐磨性的主要原因是TiC和Ni3Ti具有高硬度高耐磨性,起到抗磨骨架作用,而NiTi对TiC和Ni3Ti起到了支撑作用.堆焊层的磨损机制主要为塑性切削和硬质相的脆性剥落.     

Study on comprehensive properties of duplex austenitic surfacing alloys for impacting abrasion

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Investigation of slags in surfacing with exothermic flux-cored wires

Structures of slags of rutile–carbonate–fluorite, formed in the deposition of metal of the 8Kh3GSV2F type, are investigated. The effect of the exothermic mixture in the composition of the core of a self-shielding flux-cored wire on the composition and structure of the slag is studied. The phase composition is identified by X-ray diffraction and mass spectrum analysis and metallographic techniques. The structure of the slag, formed in surfacing with the self-shielding exothermic flux-cored wire, contains complex compounds and aluminates, whose presence influences changes of the dicalcium silicate. This has a positive effect on slag separation.     

Investigation of metallurgical processes in pulsed laser welding of nickel alloys of small thickness

Metallurgical processes taking place in pulsed laser welding of nickel alloys of small thickness are described.     

Regeneration of marine engine valves using laser surfacing

This article presents an analysis of the applicability of laser surfacing of the exhaust valve face of a marine diesel engine using cobalt-based powder. After preparation by machining, the selected valves were subjected to laser surfacing using a high-power ROFIN DL020 laser. The EuTroLoy 16012 powder was used in the surfacing process. One of the valves was cut and subjected to metallographic examination and hardness measurements, while the other valves were assembled in the engine, which worked for approx. 3000 h. The tests conducted for the initial condition showed a dendritic structure of the surfacing weld, characteristic for surfaced layers with carbide inclusions uniformly deposited in interdendritic areas and a minimally changed structure of the steel substrate. Similar tests were carried out for the valves after their period of operation. The valves' faces showed little wear. The microstructure of the surface weld was found to have minor changes mainly due to the effects of diffusion processes occurring in the operating temperature and a decrease in hardness. The laser surfacing technique has proven very useful for the regeneration of marine engine valves.     

直流横向磁场作用下钴基合金的组织及性能

为了提高堆焊层的性能,研究直流横向磁场对等离子弧堆焊层的组织和性能的影响.在低碳钢表面进行钴基合金粉末等离子弧堆焊时施加直流横向磁场,焊后对堆焊层进行硬度、磨损、显微组织以及X射线衍射分析,并系统地分析直流横向磁场对等离子堆焊层硬度和耐磨性的影响规律.结果表明,施加磁场时堆焊层性能比无磁场时堆焊层性能好.当堆焊电流为1...     

Fe3Si基合金不同热处理工艺的软化机制

Fe3 Si基合金具有优异的软磁性能 ,但由于有序相的出现导致其很强的环境脆性和本征脆性。文中采用不同的热处理工艺来研究软化机理 ,指出在再结晶温度以上采用水冷工艺能使Fe3 Si基合金得到很大程度的软化     

Thermal spraying and surfacing using flexible cord materials

Thermodiffusion galvanizing application features are considered for galvanizing tubes over 6 m long; galvanize mixtures expenditure reduction and energy saving devices are worked out. It is shown that electric power expenditure is reduced and processing cost efficiency increases at continuous operation of organizational management.