Effect of structure of autoclave nickel powder on its processing characteristics

Conclusions With increasing amount of compact granules in autoclave nickel powder reduced with hydrogen from a basic nickel carbonate pulp, the apparent density and nickel content of the powder grow. A good-quality nickel powder for flame-spraying is composed of compact granules of spherical shape.Translated from Poroshkovaya Metallurgiya, No. 9(285), pp. 10–13, September, 1986.     

Effect of laser processing on the microstructure of a structural low-carbon steel

The macro- and microstructures and the distribution of microhardness over the height and width of the remelted and heat-affected zones in structural low-carbon grade 20 steel (1020 AISI) are investigated after laser processing under various conditions, including the application of an electric arc.     

工艺参数对铁水脱锰率的影响

以宝钢用铁精矿A为脱锰剂,研究了各种工艺参数对脱锰率的影响.结果表明,铁精矿A的最佳适用温度为1500℃,最高脱硅脱锰率均达80%～90%,进一步提高加入量只会促进脱碳反应的进行,从而生成泡沫渣.为缓解泡沫渣的发生可适当降低熔渣的黏度,添加CaF2的效果优于Na2O.此外,脱锰剂中添加CaO不利于脱硅脱锰反应的进行,添加SiO2对脱硅率稍有降低,但能进一步促进脱锰.     

Effect of processing parameters on copper powder produced by novel hybrid atomisation technique

ABSTRACT

In the present work, a novel design of centrifugal atomiser for producing pure copper powder was studied. The novel complementary hybrid system provides an external stream of gas to increase the cooling rate of the atomised particles. Effects of the operating parameters, such as disc rotating speed and gas flowrate on the morphology, particle size distribution, cooling rate and microstructure, were analysed. It was evidenced from the experimental results that the median particle size in the novel atomisation process is mainly controlled by centrifugal disintegration. The microstructure of the produced powders was equiaxed and the grain size decreased with increasing gas flowrate. The cooling rate experienced by centrifugal atomised Cu powders was studied via numerical formulation estimated to be 10⁴–10^6?K?s^?1. The results show that the cooling rate is a strong function of particle size and increasing the rotating disc speed also increased the cooling rates.     

Effect of processing factors on the mechanical properties of sintered TiC-Ni-Co-Cr alloys

Conclusions Variation in the processing parameters involved in the manufacture of a TiC-base sintered hard alloy with a Ni-Co-Cr binder changes its static strength about one and a half to twofold, its dynamic strength threefold, and its resistance to abrasive and hydroabrasive wear two- to fourfold.Translated from Poroshkovaya Metallurgiya, No. 1 (169), pp. 11–16, January, 1977.     

Effect of ultrasonic refining upon the processing properties of atomized stainless steel powder

Conclusions Ultrasonic treatment in an aqueous solution containing 10% HN0₃ and 2% HF markedly increases the apparent density of the Krasnopakhorsk Plant atomized stainless steel powder and improves its flowability and compressibility. It also has a pronounced beneficial effect upon the physicomechanical properties of sintered parts.Translated from Poroshkovaya Metallurgiya, No. 10(178), pp. 82–84, October, 1977.     

金属粉末特性对选区激光熔化工艺及其制件性能影响

高品质金属粉末是选区激光熔化（selective laser melting,SLM）制备高性能制件的重要基础。粉体特性对选区激光熔化技术的影响及其机理研究是理解选区激光熔化技术不可或缺的重要组成部分。本文从粉末物理和化学特性出发,论述了粉末特性对选区激光熔化工艺、制件微观组织与性能的影响。结果表明,粉末的物理特性,尤其是粉末形貌和粉末粒度分布能显著影响其流动性和粉末床堆密度等关键工艺特性;而粉末的化学成分,特别是杂质成分,是影响制件相组成和微观组织的重要因素。在此基础上,本文进一步介绍了选区激光熔化过程中高能量源与粉末颗粒的冶金作用机理研究进展。