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Copyright of Proceedings on Quality is the property of University of Zenica, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Proceedings on Quality is the property of University of Zenica, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Toughness testing is one of the most important and most applied dynamic tests of materials. Many materials are subjected to this test in order to ensure the safety of work in adverse conditions. Thus, for steel S690QL, which is a high-strength fine-grained structural steel in the quenched and tempered state, the minimum conventional yield stress ReH of 690 MPa with guaranteed toughness (Charpy impact energy) at a temperature of -40°C of 30 J is prescribed, for rolled plates with a thickness of 3 to 50 mm. In this work, testing and analysis of the results of impact energy at a temperature of - 40°C was carried out for 10 samples of plates of different thicknesses, produced from steel S690 QL. With these tests, the aim is to consider the segments of the technological process, which have an impact on the physical-metallurgical characteristics, primarily on the formed microstructure and grain size, which affect the toughness values at low temperatures. [ABSTRACT FROM AUTHOR]

More recently modified stainless steels have been used to produce various structural elements that work in complex operating conditions. Stainless steel X8CrNiS18-9 (standard EN 10088-3: 2005) is the most commonly used austenitic stainless steel due to its good machinability. This steel has high mechanical and working properties thanks to complex alloying, primarily with the elements such as chromium and nickel. The content of sulphur present in the steel from 0.15 to 0.35% improves machinability. However, sulphur at the same time decreases the mechanical properties, particularly toughness. The addition of sulphur, which is the cheapest available additive for free machining, will impair not only the transverse strength and toughness but also the corrosion resistance. The aim of this work is to determine the influence of tellurium on the machinability, corrosion resistance and mechanical properties of the mentioned steel. [ABSTRACT FROM AUTHOR]

Steel S690 QL is a high-strength quenched and tempered, fine-grained structural steel with a minimum yield strength of ReH of 690 MPa and with guaranteed toughness (Charpy) for rolled plates with a thickness of 3 to 50 mm. This paper presents the examination and analysis of the microstructure and grain size results after quenching and tempering. Also, the aim of the examination is to consider the segments of the technological process and its influence on the physical and metallurgical characteristics, primarily on the microstructure and grain size, which affect the tensile characteristics and toughness at low temperatures. [ABSTRACT FROM AUTHOR]

The production of titanium is very expensive, so it is interesting to research technologies that require lower costs, such as the HDH hydrogenation-dehydrogenation process technology, which is used for cheaper powder production from the waste material of titanium alloys. This paper presents the hydrogenation procedure of a recycled piece of the Ti6Al7Nb titanium alloy. Hydrogenation was carried out in a furnace for heat treatment at about 700oC in a hydrogen atmosphere. After hydrogenation, samples of the Ti-Al-Nb type alloy were mechanically crushed by the grinding process to a granulation below 120 μm. [ABSTRACT FROM AUTHOR]

The aim of this work is to determinate the temperature start of precipitation of the secondary phases in austenitic stainless steels with delta ferrite. Presence of the delta ferrite in austenitic stainless steel promotes the precipitation of the secondary phases especially carbides and sigma phase whose have effect on quality of steel. The microstructure was characterized after a solution annealing at 1030 ℃ followed by annealing in temperature range from 550 to 1000 ℃ for the time of 30 minutes and cooling in air. Etched samples were observed using optical microscopy and scanning electron microscopy. The delta ferrite content was determined by a Feritscope MP30. Analysis of microstructure showed that the first phases precipitate between 550 and 650 ℃ at α/γ boundaries and delta ferrite. Sigma phase starts to precipitate between 650 and 750 ℃ at α/γ boundaries. [ABSTRACT FROM AUTHOR]

The chemical composition of casting is an important factor affecting the shape of graphite and the mechanical properties and microstructure of the metal base. Different elements have different influence to casting properties. All elements that affect the microstructure development during casting solidification have significant influence on mechanical properties of the castings. In the practical part of this paper influence of molybdenum and chromium on the change in hardness and pearlite content in the microstructure is presented. The results show that with the addition of pearlitizing elements (Cr and Mo), the content of pearlite in the microstructure of the metallic matrix and hardness of the castings increase. [ABSTRACT FROM AUTHOR]

Dual phase steels are low carbon steels which are thermo-mechanically processed to getting better formability and toughness than ferrite-perlite steels with similar tensile strength. The microstructure of these steels consisting of a ferrite matrix with hard martensitic/bainitic second phase. The concept of representative volume element (RVE) is critical to understand and predict the behavior of effective parameters of steels. The RVE is considered to be a partial volume of the material, which is statistically homogeneous from the macroscopic point of view. In this paper determination of the representative volume of two dual phase steels (one with a martensitic and the second with a bainitic) is presented. Multiple samples are excised from the total volume of tomography and different parameters are observed to get the smallest RVE with stabile parameters. Results show that size of reduced volume has an influence on the parameterstability, while position of the observed reduced volume has not. [ABSTRACT FROM AUTHOR]

The basic characteristics of the chemical composition of steel with improved machinability (X8CrNiS18-9) are the increased content of sulphur (0.15-0.45%), phosphorus (0.07-0.11%) and manganese (0.5-1.5%). Sulphur by creating sulphide inclusions reduces friction and cutting resistance, and increases the brittleness of the chip. Considering its harmful effect in steel, as well as the fact that non-metallic inclusions have been insufficiently tested for this type of high-alloyed steel, the aim of this research is to determine by microalloying the possibility of modification of non-metallic inclusions. Modification with boron and zirconium favorably affects the ductile properties of steel, and a step forward in this study is a modification of inclusions with tellurium. It is of particular importance to determine the behavior of non-metallic inclusions in the process of production of the structural part and in subsequent exploitation. Therefore, plastic processing of austenitic stainless steel was also carried out, forging and rolling with two different level of processing. [ABSTRACT FROM AUTHOR]

Copyright of Proceedings on Quality is the property of University of Zenica, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

More recently a modified stainless steels have been used to produce various structural elements that work in complex operating conditions. Stainless steel X8CrNiS18-9 (standard EN 10088-3: 2005) is the most commonly used austenitic stainless steel due to its good machinability. This steel has high mechanical and working properties thanks to a complex alloying, primarily with the elements such as chromium and nickel. The content of sulfur present in the steel from 0.15 to 0.35% improves machinability. However, while sulfur improves machinability at the same time decreases the mechanical properties particularly toughness. The aim of this work is to determine the influence of boron, zirconium and tellurium on the mechanical properties the mentioned steel. Change of mechanical properties, depending on the chemical composition of the steel is simulated with MATLAB program. [ABSTRACT FROM AUTHOR]

This paper describes a few examples of the recovery of manganese from steel slag and dust by using different technologies based on acid leaching. Reductive leaching in sulfuric acid (H2SO4) for recovery of manganese from electric arc furnace dust (EAFD) was represented. Recovery of manganese and iron was increased with increasing in the sulfuric acid concentration. By using different reductantcs such as oxalic acid and hydrogen peroxide were revealed a higher manganese recovery than the other reductants. The results were showed that leaching of manganese was accomplished at 0.31 mol/L oxalic acid concentration, 2 mol/L H2SO4, a liquid/solid ratio of 30/1 at 70 °C and with 90 min leaching time. [ABSTRACT FROM AUTHOR]