Mihails Lisicins

Screen Elements Made of Perforated Steel Tape and their Application for Shielding Electromagnetic Fields

In the present work the methods for producing flat and three-dimensional shielding screens from the perforated steel tape are proposed. The possible application variants of mentioned screens are offered and analyzed. Main attention is given for producing one-layer and multi-layer screens with cellular structure due to its relatively low weight and technological elasticity – complex three-dimensional structures could be done successfully.Examples of produced shielding screens from the perforated steel tape for protection from electromagnetic fields in different frequency range are offered and tested. The efficiency of a shielding material was determined by measuring the magnetic field before and after applying the shielding material. Distribution of the magnetic field behind the shielding screen was determined by software vector mapping. Shielding efficiency was measured for 1) a three-layer perforated steel screen; 2) an one-layer perforated steel screen - shielding screen was placed in between the magnetic field source and the measurement point forming a two dimensional screen; 3) copper composite sprayed screen. During experimental investigation it was established, that a three-layer perforated steel screen application allowed the 27% reduction in the magnetic field, while one-layer perforated steel screen gave only 12% reduction. Copper composite sprayed screen reduced magnetic field by 15%.Recommendations for producing the multi-layer perforated steel screen accordingly to shielding efficiency are elaborated and laid down. The discussed material carries also ecological significance, since the material is produced by waste products (after stumping etc.). Therefore the production of such materials comes with reduced cost both in light of capital expenditures and ecological footprint.

Band structures for binding and holding of objects made from recycled metallic materials

The aim of the present research is the investigation of the possibility and effectiveness of using the band structures made from recycled metallic materials for binding and holding of objects (in particular, tubular objects as pipelines or shells). The using of band elements and structures as such is a perspective way to increase the safety and bearing capacity of the pipelines and vessels. Nowadays during repair works the outer surfaces of the mentioned objects are braided by the steel tapes, i.e. the objects are strengthened by the binding. The mentioned steel bands are specially produced for binding purpose. From the other hand after stamping of smallsize details (like the elements of supply chains for different apparatus) the metallic waste in the shape of perforated metallic tapes are received and needs to be reused in compliance with the good practice in effective resource using and recycling. The band structures for binding and holding of tubular objects, produced from the perforated metallic tape by the longitudinal profiling, multilayer and spiral winding are presented. It is proposed to apply in industry the composite band structures made from perforated metallic materials and epoxy matrix for binding and holding of tubular objects as pipelines or shells, which allows simplifying and speeding up the repair works especially in the cases of the local damages.

Hardening of Steel Perforated Tape by Nd:YAG Laser

One of the directions of application of the perforated metal material is their use as cutting elements in the production of processing tools. In this case it is necessary to carry out hardening of cutting surfaces to increase their hardness. One of the methods of hardening metals could be laser treatment. Therefore, the present work is a study of the effect of Nd:YAG laser radiation on the microstructure and hardness of fragments formed from steel perforated tape. Different laser scan speeds (doses) were used in the experiments. The results have shown that the increase the microhardness of 30-40% after the laser treatment of steel perforated tape in the surface layer in a depth range up to 1 μm take place. The studies of microstructure of fragments formed from steel perforated tape have shown the reduction of the structure size and the presence of a thin oxide compounds, which is consistent with the results on nanoindentation. Hardening of the metal by laser radiation is carried out without surface melting which eliminates the change of macroroughness and the need for subsequent machining process.