Papers by Author: Tomasz Cyryl Dyl

Abstract: The paper presents effect of burnishing broaching process on the geometric structure of the steel tubes. Burnishing is a plastic surface treatment. Processing tools are hard and smooth surface. Burnishing elements of are ball, roll and disk. Burnishing be flat surfaces, and cylindrical shape. Burnished surfaces are cylindrical outer and inner. Because of the type of the force can be divided into static and dynamic burnishing. Due to the kinematics can be divided into sliding and roller burnishing. Occurrence of moving parts in direct contact with the material qualifies for the group process of burnishing rolling. The sliding burnishing design element property is part of the work surface burnished permanently attached to the handle. Burnishing is used as a finishing strengthens and smoothness, can be realized on the universal machine tools and machining centers, effectively replaces the machining operations such as grinding, reaming, honing and lapping.

Abstract: Coatings of metal and ceramic composite were applied on the steel specimens using the subsonic process of flame spraying. The specimens were then subjected to both cold and hot plastic working by rolling and also cold pressing by the hydraulic press. Plastic working is an alternative to machining, as the method of finishing of coats applied by flame spraying. The article presents the findings of the research into the possibility of using plastic working (hot and cold rolling and pressing) to obtain the corrosion properties of the flame sprayed Ni-Al alloy coatings and Ni-Al-Al₂O₃ composite coatings. The alloy coatings had a single-phase structure, of the maximum 10% aluminium solubility in the crystal lattice of nickel, whereas in the composite coatings the volume content of non-metallic material Al₂O₃ was 15% and 30 %. After finishing the adhesion reduction, cracks on the surface and cross-sections of coatings was not observed. The largest value of strain hardening of alloy coating Ni-5%Al was stated after pressing. The composite coatings obtain by flame spraying be characterized by big surface roughness (R_a = 13.3 µm). The plastic working caused decrease surface roughness. Minimum value of R_a parameter was observed after hot rolling. It was found that maximal roughness was presented after pressing. The corrosion tests were performed in 0.01 M H₂SO₄ solution by potentiokinetic technique. The article presents the effect of dispersion phase of Al₂O₃ on corrosion properties of composite coatings on the nickel base. The corrosion rate was dependent on method of plastic working. The increasing drafts resulted in rise corrosion current density and decrease in value of corrosion potential.

Abstract: Modern materials on intermetallic matrix are in the scope of research of many scientific – research centers in Poland [1]. Intermetallic systematic alloys containing aluminium have high resistance to oxidation, abrasive corrosion and fatigue as well as heat resistance. That is why they are applied in the production of machine parts used in hard service conditions (internal combustion turbine blades, exhaust valves, turbo-blower rotors) [2]. Intermetallic coatings can be obtained by means of plasma spraying. Thermal spraying technology is widely used due to the possibility of increasing the service properties in surface layers (strength property, tribological, anti-corrosive and decorative property) as well as coating application on machine parts elements, on tools for plastic working (forging moulds busters, piston rods, gear wheels teeth, crank journals, valve seats, and combustion engine cylinders) [3, 4]. NiAl and Ni3Al coatings are characterized by high fatigue resistance, heat resistance and considerable corrosion resistance [5]. Coatings obtained by thermal spraying have high surface roughness. Thus, subsequent plastic treatment is advisable for plasma-sprayed intermetallic coatings. Therefore it is vital to define to what extent the change of unit pressure will influence reduction of surface roughness of intermetallic coatings. For this purpose experimental upsetting research was carried out on C45 steel samples having NiAl and Ni3Al coatings for the following unit pressures p = 500 MPa, p = 800 MPa, p = 1100 MPa.

Abstract: The paper presents finite element analysis of spreading process of hollow steel tubes implemented within commercial software MES FORGE2-V3.0. To this purpose, rigid-plastic model of deformed material was assumed. The analysis was realised for hollow tube made from steel C45 with external diameter D0 = 50 mm and internal one d0 = 40 mm. Distributions of temperature, stress and deformation for different values of gradient radius of mandrel  (1535) and different friction conditions on the area of metal-tool were determined. With the piercing press the billet is introduced into a vertical or horizontal die, subsequently to be pierced by mandrel. Afterwards pipe is elongated in Diescher’s mill. Hollow steel tubes undergo hot deformation spreading process in two-roll press by mandrel. Process stability depends on dimensions of the hollow tube and mandrel: tube external diameter, tube internal diameter, mandrel diameter and inclination angle of mandrel. Increase of external diameter of hollow tube occurs in the course of spreading process by mandrel. Process parameters depend on chemical composition and type of material. In this paper the contact problem in metal – tool interface is considered. Burnishing implies the sizing of a hollow tube by its plastic spreading.

Abstract: The paper presents the effect of dispersion phase of Al2O3 on selected potential properties of composite coatings on the nickel base. Coatings of Ni-Al-Al2O3 were applied on the steel specimens using the subsonic process of flame spraying. The specimens were then subjected to both cold and hot plastic working by rolling and also cold pressing by the hydraulic press. Plastic working is an alternative to machining, as the method of finishing of coats applied by flame spraying. The paper presents the findings of the research into the possibility of using plastic working (hot and cold rolling and pressing) to obtain the selected properties of the flame sprayed Ni-Al alloy coatings and Ni-Al-Al2O3 composite coatings. The alloy coatings had a single-phase structure, namely boundary solution α , of the maximum 10% aluminium solubility in the crystal lattice of nickel, whereas in the composite coatings the volume content of non-metallic material Al2O3 was: 0, 15, and 30 %.