International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

We have studied electromagnetic and corrosive properties of new soft-magnetic composite materials made from iron powder ASC 100.29 and Atomet 1001HP, surface of which is encapsulated by insulating anticorrosive oxide coating. The results demonstrate that the use of such materials in power supplies, chokes, transformers, stators and rotors of electrical machines and other devices ensures their stable operation under various conditions.

Iron powder metallurgy is a method that is widely used in production of steel parts that are utilized as machine components or as parts in automotive industry. Milling is extensively used in powder metallurgy of iron, for purposes of mixing. The hardness and yield strength of milled iron powders increase due to work hardening. This leads to low green density of the cold pressed green parts, prior to sintering. In powder metallurgy, warm compaction is utilized for enhancing the green density and green strength.
In the present study, effect of warm compaction of milled iron powders was investigated. For warm compaction of iron powders, 600 MPa pressure was applied in a steel die at 150 oC. The microstructure of the milled samples was examined by scanning electron microscopy. Hardness values of the cold pressed and warm compacted samples were determined by a Brinell hardness tester. Bending strength values of the samples were determined by a universal testing machine. It was found that the hardness of the cold compacted green samples increased considerably, from about 40 Brinell10 to about 140 Brinell10, as a result of warm compaction. Bending strength values increased to over 100 MPa after warm compaction; whereas the bending strength of the cold compacted green samples were in 10-20 MPa range.

Surface saturation with boron of Fe-C-Cu construction powder materials aims to improve the surface hardness of the articles and hence improve wear, contact strength and other mechanical properties. This study investigates the influence of single-component diffusion enrichment modes with boron of semi-permeable powder metallurgical samples from the Fe-C-Cu system. The powder samples on the basis of iron powders NC 100.24 to which 0,3 ÷ 2,5% Cu and 0,4% carbon were added were subjected to the study. Diffusion saturation with boron was carried out in semi-permeable saturation media with a composition of 84% Na2B4O7 + 12% SiC + 4% K2Cr2O7 at temperatures 850 ÷ 950 ° C for 2 ÷ 4 hours. Graphical dependencies are presented for the variation of the diffusion slit thickness in the longitudinal section of the test samples depending on their density, duration and saturation temperature. The experimental results obtained are compared with those obtained by combining pure iron samples with the same technological parameters.

The aim of the present paper is to test the synthesis of moulded metal composites (MMCs) with a metal matrix Al and a strengthening metal phase Fe of type „in vitro” and „hybrid”. There was a test done for the preparation of composites using a method similar to “capillary forming”, such as the metal matrix (melt of aluminium) was infiltrated in the space between the iron blasting grit which is the inversely option of solving similar problem in which problems the blasting grit (the strengthening phase) are forcibly implemented into the melts (the metal matrix). In this way the problem which needs to be solved, in which the melt is infiltrated between the space of the iron blasting grit, allows for the maximum reduction of the volume of the metal matrix on account of the strengthening phase. The experiments were conducted with laboratory equipment elaborated on the base of another equipment for "capillary forming" with extra vacuum, patent protected developed by the department ”Materials Science and Technology”. From the received moulded metal composites (MMCs) were establish areas of reaction between aluminium and the iron powder. The experiment produced significant results as received alloying between iron and aluminium at a relatively low temperature of melting of the iron in which there were received metal-composites structures of the type „in vitro” and „hybrid”, which were tested by metallography and micro-hardness analysis.