Open Access Conference Proceedings

Abstract: The article presents the results of tests of influence of the thermo-mechanical treatment parameters (such as temperature, cooling conditions) on the mechanical properties and microstructure of steel 23MnB4 indicated for cold-heading. The process of rolling was conducted in simulation in continuous finishing train arrangement of four rolling stands in a laboratory of Faculty of Metallurgy and Materials Engineering VSB Ostrava. [..] Read more

Abstract: This paper provides a discussion on results of plastometric tests of selected steel grades used to manufacture pipeline components for the power engineering applications as well as for the gas and petroleum industry The formability assessment was conducted under compression conditions using a thermal-mechanical Gleeble simulator. Studies on the dependence of flow stress σp on strain e were conducted at the temperature ranging from 20 to 1100 °C and the strain rate of 1 s-1. [..] Read more

Abstract: High alloy heat resistance steels based on 12% Cr content are characterized by specific structure and properties, which can substantially complicate technological procedure of their forming. These 12 % Cr based steel are characterized by increased resistance to deformation that affects-their formability significantly, quit narrow interval of forging temperatures, non-uniform formability and high sensitivity to stresses. [..] Read more

Abstract: In this study, a commercially acquired Ni-rich (50.0~50.8at% Ni) Ni-Ti shape memory alloy sheet having the thickness of 0.9 mm was cut in the shape of a circle with a diameter of 36 mm and placed in a heated chamber at 800°C for one hour and then quenched in water, which served as a solid solution process affiliated to an annealing process. This sheet blank was then stretch formed with a hemispherical punch of 30 mm in diameter to a stroke 1 mm, 2 mm, 3 mm, and 4 mm, respectively. [..] Read more

Abstract: Since the use of cold-rolled steel sections is a standard method in mechanical engineering and steelwork and cost efficiency is always a big issue, it is of great interest to address the highly non convex problem of cross-section optimisation. At a first glance classic genetic algorithms already seem to be suitable for this problem, because they are powerful search heuristics for solutions in non convex problems. [..] Read more

Abstract: Martensitic heat-resistant steel P92 belongs to very progressive group of 9-12% Cr steels modified with vanadium and niobium, with controlled boron and nitrogen content. P92 has got excellent creep properties and it is used very often to build the most exposed parts of supercritical units in steam power plants.The goal of this article is to compare the real welded joints with the simulated samples and to optimize the heat treatment and welding process of P92 steel. [..] Read more

Abstract: The work deals with chosen properties of bimetal weld and its neighbourhood of Ti-clad Cr/Ni steel after one or double heat treatment (at 600 °C / 1.5 h / air) applied after explosive bonding. Notch impact strength values were compared with bimetal weld of C-Mn steel bonded with Ti after the same heat treatments. [..] Read more

Abstract: This paper analyzes, by comparison, the cavitation erosion resistance of the samples treated through softening annealing at 710 ± 10 °C with the purpose of partial spheroidization of pearlite and decomposition of free cementite traces from the microstructure, respectively the samples treated through normalizing at 860 ± 10 °C with the purpose of the pearlite proportion increasing and the cavitation erosion resistance improving. Cavitation tests were conducted on a vibrating device with piezo-ceramic crystals, following standard rules ASTM G32-2010.The microstructure characterization of the heat treated and eroded by cavitation was made by optic microscopy, and scan electronic microscopy.The obtained results show an improvement of cavitation erosion resistance after the application of the heat treatment for normalizing as a follow-up of the structure finishing and growing of the pearlite proportion in the base matrix.. [..] Read more

Abstract: The paper sets out a synergic program by MAG pulsed welding of Duplex stainless steel plates with thickness of 12 mm. The selected filler material was a E2209-16 wire with a diameter of 1.2 mm and as shielding gas Cronigon 2 was used.The root layer was obtained at lower linear energy, of 6.9 kJ/cm, and for the filling layers the heat input was different namely: 10 kJ/cm, 15 kJ/cm and 20.7 kJ/cm. [..] Read more

Abstract: Currently, one of the modern techniques for improving the surface properties of the stainless steel is the nitrating thermo chemical treatment. The research conducted in this paper aims at forming coatings with high hardness on the surface of Duplex stainless steel X2CrNiMoN22-5-3. [..] Read more

Abstract: The methods of intensive plastic deformation SPD (Severe Plastic Deformation) belong to a group of very attractive means of increasing utility properties of metallic materials (strength and structural characteristics). The paper is focused on numerical simulation forming of high-carbon steel C55E processed by the SPD DRECE (Dual Rolling Equal Channel Extrusion) and GTAW-141 welding process by Simufact software. [..] Read more

Abstract: The work deals with two types of high entropy alloys (HEAs) of Fe4CrCuMnNi and Fe4CrCuMnNi type, which were laboratory synthesized by vacuum arc-melting method. Much cheaper Fe of higher portion replaced cobalt in high entropy alloy of CoCuCrMnNi type. [..] Read more

Abstract: The harmful effect of cavitation is the erosion of the material. Although there are many studies on improving the mechanical properties of the material in order to increase resistance to cavitation so far none has defined the optimal solution for complete protection against this type of wear. [..] Read more

Abstract: Some surface treatments that apply to the hydraulic equipment components, which operated at high hydrodynamic loads, in which appear the phenomenon of erosion by cavitation, shall be listed and laser nitriding. Before that operation, the steel was undergone thermal annealing treatments for improving machinability cutting, followed by martensitic quenching and a tempering to high temperature. [..] Read more

Abstract: Today, advanced steels which are used in the automotive industry are required to possess high strength and ductility. Two heat treatment methods capable of meeting these requirements were tried in the present experimental programme that involved selected types of steels. [..] Read more

Abstract: During heat treatment of carburized steel parts, the transformation of austenite to martensite occurs and a certain amount of retained austenite remains in the hardened layers. The higher content of retained austenite in the carburized layer adversely influences hardness and frictional characteristics and increases susceptibility to fatigue damage. [..] Read more

Abstract: Increasing demand on materials characterization together with improvements in apparatus testing lead to the development of new testing procedures such as sub-size specimens testing. Miniaturized specimens allow reliable properties determination while using very small amount of material.These methods are widely used for local material properties determination. [..] Read more

Abstract: The paper deals with the change of the structure and mechanical properties of the austenitic steels after the exposure at the critical temperature. The effect of the bend radius of tubes on the mechanical properties and the structure was studied. [..] Read more

Abstract: A numerical method of simulation of evolution of complex precipitates in multiphase multicomponent systems is suggested. This method is based on the mean field approximation for the description of evolution of the pre-existing particles and on the classical theory of nucleation for calculation of the rate of formation of new nuclei. [..] Read more

Abstract: Operating life and reliability of steam boiler and piping systems are considerably determined by long-term creep rupture strength (CRS) of welded joints of boiler tubes and pipes. Consequently, the appreciable research effort has been focused to reveal the most important factors affecting the creep properties of weldments. [..] Read more