The structure of composite rollers with iron or nickel-iron base and hard surface layer of WC or TiC based hard alloy produced by the method of hot vacuum pressing with a liquid phase

In this work the structure and properties of composite rollers with surface layer made of hard alloy were studied. The rollers were made by the powder metallurgy method with sintering during pressing and the presence of a certain liquid phase during sintering (semi-liquid sintering). WC-Co and TiC-Ni-Fe materials were used as hard alloys. Iron-carbon and iron-nickel materials were used as soft base. All of the composite layers were formed in one process. The structure of base materials and border layer of these composites were studied. Investigations of thermocycling sustainability of these composite samples were carried out.

Computation of SIFs for cracked FGMs under mechanical and thermal loadings

The objective of this study is to present a numerical modeling of mixed-mode fracture in isotropic functionally graded materials (FGMs), under mechanical and thermal loading conditions. In this paper, a modified displacement extrapolation technique (DET) was proposed to calculate the stress intensity factor (SIFs) for isotropic FGMs. Using the Ansys Parametric Design Language APDL, the continuous variations of the material properties are incorporated by specified parameters at the centroid of each element. Three numerical examples are presented to evaluate the accuracy of SIFs calculated by the proposed method. Comparisons have been made between the SIFs predicted by the DET and the available reference solutions in the current literature. A good agreement is obtained between the results of the DET and the reference solutions.

Parametric study of friction stir welding using elastic return

Aluminum alloy is a very useful material in light manufacturing. Friction stir welding (FSW) is a solid state assembly process that is achievable for this material. This work aims to characterize the quality of the weld joint by an operation of shaping (folding), it aims to study the rate of elastic return in this weld joint after a folding operation. In this context, the elastic return for the folding process has been modeled using experimental tests under optimal welding conditions.

Numerical study of a cracked pipeline under internal pressure

In the industrial sectors, pipelines have been used as the most economical and safe means of transporting oil and gas (Pipelines). However, the number of accidents has increased considerably as their use has increased. As a result of the operating load and the pressure used, the thickness of the tube must be increased and the mechanical characteristics improved. This approach was applied to predict the growth of crack effect in samples of two pipelines at given thicknesses and pressures. We created cracks with deferential dimensions in both API X80 steel pipelines, with an application of deferential internal pressures. For the simulations, we used the code ANSYS.

The use of Gage R&R in suitability analysis of a CMM used at FAMOT Pleszew

The subject of the article is the suitability analysis of a measuring system, specifically the Zeiss MMZ T 20 30 16 coordinate-measuring machine utilizing an extended procedure.The article outlines the measurement preparation process and presents the research station as well as the procedure for determining Repeatability & Reproducibility (R&R).

On the analysis of chip shaping after finishing turning of Ti6Al4V titanium alloy under dry, wet and MQL conditions

The shape and type of chip give general information about the cutting process. This paper presents the results of testing the shape and type of chips of Ti6Al4V titanium alloy after it finishes turning. The process was carried out under dry, wet and MQL (Minimum Quantity Lubrication) conditions at variable cutting speeds and feed rates and a constant depth of cutting. For planning the tests, the PSI (Parameter Space Investigation) method was used, which allows the experiment to be carried out while minimizing the number of experience points. It was found that the cutting speed and feed affect the type and shape of the chip, and clear differences were observed between dry and wet cooling conditions, and MQL conditions. During turning, the intensity of the cutting speed and feed influence on the chip compression ratio was changed. It was similar for dry and wet cooling conditions but smaller for MQL conditions. The purpose of this research is to analyze the chip shaping when Ti6Al4V titanium alloy finishes turning under dry, wet and MQL cooling conditions.

Geometrical structure of surface after turning of 316L stainless steel in laser assisted conditions

The effects of turning 316L steel in a laser assisted machining are presented in this paper. The properties of 316L stainless steel are also shown in this article. In order to show correlation between the technological parameters, microgeometry of cutting tools and geometrical structure of surface, turning of material in grade 316L supported by laser has been executed. In addition, optical examination of cutting inserts has been performed and geometrical measurements of machined surfaces have been taken. The results of researches on the effects of the technological parameters and cutting tool’s microgeometry on the geometrical structure of the 316L steel surface after turning in LAM conditions are described.

Vibration and displacement analysis during turning of hardened steel

This paper presents an analysis of the vibrations and displacements of the tool during the turning of hardened steel for various turning parameters. Studies have shown that an increase in feed from 0.1 to 0.35 mm / rev results in an almost twofold increase in radial displacement of the tool. It has also been shown that the combination of high feeds and high rotational speed of the workpiece causes a rapid increase in vibration in all directions.

Bending of an annular three-layer circular plate

The main objective of this work is the numerical analysis of the strength and stiffness of an annular three-layer circular plate with variable mechanical properties of the core. The plates are subjected to bending. Numerical analysis of the deflection phenomenon is carried out under different support conditions of the plate. Furthermore, the influence of the material properties of the core (linear and non-linear model) on the shear stresses and deflecions is also investigated.

Influence of heat treatment on the structure and properties of polyamide 6/ halloysite nanocomposites

The nanocomposites of polyamide 6 (PA6) with halloysite nanotubes (HNT) were prepared by extrusion using co-rotating twin-screw extruder and then the standard test specimens were injected using a screw injection moulding machine. The content of HNT in the nanocomposites was 5 or 10 weight percent. The heat treatment of unmodified PA6 and nanocomposites was carried out in silicone oil in temp. 150±2°C. The samples were annealed for 3 hours and then cooled at a rate of 4 K/min. Differential scanning calorimetry (DSC) causes annealing to increase the crystallinity of the polyamide matrix. After an annealing treatment a nanocomposite with better mechanical properties was obtained. Halloysite nanotubes in polyamide matrix play the role of a nucleating agent.