Concept for technology development and research planning in iron powder metallurgy

Abstract

It was concluded in [ 1 ] on the basis of an analysis of the current status of iron powder metallurgy that it would be expedient to establish small-scale production facilities based on a regional principle. Our experience shows that it is most efficient to organize such production directly at existing metallurgical plants. At plants with a complete metallurgical production cycle, the raw material for producing the powder could be in the form of ore and concentrate, melts of pig iron, a semifinished product, steel, or mill by-products (Fig. 1). The powder production technology is chosen on the basis of the required properties of the final product. If large quantities of molten metal are available, then naturally atomization would be the most expedient method. Powders with a wide range of properties and compositions can be obtained by this technology, depending on the energy carrier (air, water, nitrogen). Mill scale is a traditional raw material for powder production, but careful sorting according to chemical composition is required in this case. This is most simply done directly at the metallurgical plant. The problem of reducing the scale and atomized powders is most easily resolved when the plant has reducing and protective media. Spent pickling solutions constitute another raw material for making iron powders. The iron salts obtained after their corresponding treatment are best decomposed to iron oxides or are used for the direct production of iron powder; first, it is necessary to achieve the required level of purity in the finished product. A technology for producing powder directly from ores and concentrates by methods involving the use of chlorides and soda was developed and tested on a semi-industrial scale at the "Tulachermet" Scientific-Industrial Association. We believe that this technology should be again considered for commercial use after the necessary improvements have been made to the equipment. Figure 2 presents a general diagram of the areas of active research into the powder metallurgy of iron: individual stages of the production cycle are being modeled as part of the overall design process; data is being accumulated on the properties of the products that are obtained and is being stored in databases with allowance for the literature data and patent research; the optimum areas of application of materials are being determined and the findings are being introduced on an industrial scale. Let us examine the concept being proposed here by using a technology for obtaining iron powder by the chloride method as an example. For the sake of specificity in solving the given problem, we take titanium-magnetite concentrate of the following composition (%) as the initial raw material: Fe -62; V -0.37; Ti -1.6; Cr -0.06; Mn -0.17; Si -1.6; A1 -1.3; Ca -0.6. In this case, the powder cannot be obtained directly by reducing iron from oxides, due to the high content of hard-to-reduce elements in the concentrate. Use of the soda-based technology makes it possible to increase the iron content of the final product ...