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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.)

The paper describes the determination of the mechanical properties of the spherical floors of pressure vessels, obtained by the welding process and shaped by the process of gradual local deformation in the cold state, i.e. by the process of Incremental sheet forming (ISF). Spherical cylindrical bottoms are an integral part of most closed-pressure vessels. Cylindrical pressure vessel floors are made from one part, but the standards also allow for welded construction when the dimensions of the floors are larger than the standard dimensions of the sheet metal for production. Pressure vessel floors obtained by the welding process and shaped by the process of gradual local deformation in the cold state, i.e. by the process of incremental deformation, have a multiaxial initial stress state, which differs significantly from the initial stress state of the cylindrical part of the vessel. Checking the behavior of such floors before completing the vessel itself, i.e. before putting it into operation, is necessary, on the one hand, due to a large number of influencing factors, and on the other hand, due to the high cost of testing the real construction itself. The aim of the test is to determine the influence of the parameter: type of material, thickness, and diameter on the following quantities: mechanical properties, ReH, Rm, A5, and total energy used for impact, KV. [ABSTRACT FROM AUTHOR]

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]

Austempered ductile iron is the last addition to the group of ductile irons obtained by isothermal improvement of classic ductile iron. Austempered nodular cast iron has improved mechanical properties and a different matrix microstructure compared to known iron-based castings. This type of casting is obtained by isothermal improvement - austempering, whereby the resulting microstructure consists of a mixture of ausferitic (acicular) ferrite and residual, isothermally transformed, carbon-enriched, stable, austenite. Changing the austempering parameters (temperature and time of austenitization and isothermal transformation) affects the obtained ausferite microstructure, and thus the mechanical properties. The most influential parameter that affects the mechanical properties of austempered ductile iron is the isothermal transformation temperature. This paper will present the relationship between microhardness values and microstructural transformations in the material due to the effect of elevated temperatures. [ABSTRACT FROM AUTHOR]

Mine development imposes very high technical requirements of the mine hoisting equipment in terms of speed of transport. To meet these requirements it is necessary to properly design the structural elements of mine hoisting equipment which means that they must have the proper characteristics of the materials from which they are made such as mechanical properties. The suspension lever is an important fixing part of mining installations export container. Since the suspension levers are exposed to dynamic loads during operation, one of the most important test is a determination of their dynamical strength. This paper presents the determination of the dynamic strength of a new suspension lever and a suspension lever that has been in use for several years. Based on these parameters further working life of the suspension lever can be determined in order to increase the safety of the entire plant. [ABSTRACT FROM AUTHOR]

The precipitation of sigma (σ) phase in austenitic stainless steels is a significant subject of many investigations. Exposure of these steels to elevated temperatures (from 600 °C to 900 °C) results in precipitation of σ phase (transformation product from delta (δ) ferrite) which is one of the main reasons for the deterioration austenitic stainless steels properties. It is therefore of considerable interest to study the conditions for σ phase formation, as well as the mechanism of the transformation. This review paper presents overview of precipitation characteristics (including morphologies and precipitation sites) as well as effect of σ phase on properties of austenitic stainless steels. It is particularly highlighted that the precipitation of hard, brittle and nonmagnetic σ phase occurring preferentially at δ/γ phase boundary and within δ ferrite islands (high Cr concentrated region) cause worse mechanical properties (impact toughness and elongation) and corrosion resistance. [ABSTRACT FROM AUTHOR]

The HK30Nb steel pipe casting was obtained by centrifugal casting. This steel is austenitic stainless steel grade AISI HK 30 and is standardized according to ASME SA-351 in as cast condition. HK 30 Nb steels not standardized i.e. it is HK 30 steel modified with niobium. In addition to the required mechanical properties, this steel is also tested for heat resistance because it is used at high temperatures. In this paper, the heat resistance testing was carried out on the HK 30 Nb stainless steel pipe casting for two temperatures (750 and 850 °C) according to the standard ASTM G 54-84. The mass change and rate of oxidation for different heating times (24, 48, 72, 96 and 120 hours) were determined. The results of the study are significant for the continued use of these materials at high temperatures in exploitation conditions. [ABSTRACT FROM AUTHOR]

Surface roughness is the totality of microgeometric irregularities on the surface of an object and it is caused by various factors, from which the most important are machining and processing techniques. This characteristic of the material is very important, especially in the case of high-quality materials designed for the demanding conditions of exploitation. In this work the tests of surface roughness Nimonic 80A were carried out. The tests were performed after the different tehnological phases during processing of Nimonic 80A using Sutronic 10 instrument. This instrument work on the principle of ultrasound which measures the aritmetic value of Ra, i.e. parameter for determining the surface roughness. [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.)

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]

The great development of the industry has caused the need for systematization in the classification of raw materials and finished products. For this reason, all industrialized countries have their own standards, so called national standards or norms for production and delivery. With the unification of European countries, and also for the import and export of products and raw materials, the so called- European standard or EN (euro norm) took the primacy. Thus, the designation of steel according to the EN standard has been taken into consideration, and as a standard for designation of steel and therefore steel casting in our country, the designation according to EN standards has been taken over by some of the methods of takeover. Thus, the European standards with the prefix BAS become Bosnian standards. Standards for designation of steel and steel products are basic for metallurgy and metal industry and are very often in B&H they are translated versions of European standards. However, any change or revision of the European standard requires the same for the BAS standards, and in this paper will be presented the latest changes to the EN and BAS standards related to the "Designation system for steels", i.e. changes will be shown for the basic standards, respectively EN 10027-1 and 10027-2 or BAS EN 10027-1 and BAS EN 10027-2. [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.)

Copyright of Proceedings on Metallic & Nonmetallic Materials is the property of University of Zenica, Faculty of Metallurgy & Technology 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 Metallic & Nonmetallic Materials is the property of University of Zenica, Faculty of Metallurgy & Technology 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.)

Copyright of Proceedings on Metallic & Nonmetallic Materials is the property of University of Zenica, Faculty of Metallurgy & Technology 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.)