Search

Long-term exposure of superheater and steam intermediate superheater pipe materials to high temperatures in the operating conditions that prevail in thermal power plants leads to the appearance of the oxide layer. Oxide layer forms on the inner wall of the pipe, which acts as a heat insulator and reduces heat transfer through the pipe wall. The action of the oxide layer as an insulator and limiting the transfer of heat to water vapor inside the pipe leads to overheating of the pipe wall. This paper presents the measurement of the thickness of the oxide layer on the outer and inner side of the pipeusing the standard method BAS EN ISO 1463:2022 with a presentation of the measurement results with pronounced measurement uncertainty. [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]

Proper calibration of the device is important to prevent potential sources of error, which ensures that the test results most effectively represent the value of the sample being tested. In microhardness testing, the loading force does not exceed 1.96 N. The test surface requires a more complex metallographic preparation, and the smaller the injection force, the surface must be finer prepared. Precision measuring microscopes with an accuracy of ± 0,5μm are used to measure the size of the prints. Calibration of the Zwick Microhardness Testing Device of the Kemal Kapetanović Institute Metallographic Laboratory was performed for measuring ranges HV 0.3. The permissible deviation of the device including the measurement uncertainty shall meet the requirements of the standard for this area. [ABSTRACT FROM AUTHOR]

Metallic materials thanks to the excellent combination of data on material properties are obtained by standardized and agreed testing of samples made from semi-finished or finished products. Metallic materials can be tested by different testing techniques. One of them is metallographic testing, for which a light microscope is used as a basic device. In order for the test workability and strength are very important construction materials. The most complete and most accessible group of results to the light microscope were reliable it is necessary to calibrate the microscope according to certain standards and guidelines, and by the national metrology standards. This paper describes the procedure for calibration of the light microscope at the Metallographic Laboratory at the Institute "Kemal Kapetanović" in Zenica, University of Zenica. [ABSTRACT FROM AUTHOR]

In modern times, the science of materials cannot be imagined without metallography. The history of metallographic testing in Bosnia and Herzegovina is primarily related to Zenica. Today, most of the research related to the metal industry in BiH is conducted in laboratories at the Kemal Kapetanović Institute in Zenica. The Institute's Metallographic Laboratory has a history to be proud of and a future to nurture. This paper will review the capabilities of the Institute's Metallographic Laboratory 30 years ago and now. [ABSTRACT FROM AUTHOR]

Non-metallic inclusions usually deteriorate mechanical properties and surface quality of steel products. Presence of non-metallic inclusions might have negative affected some of the mechanical properties of steels like ductility, toughness, anisotropy, and formability. Macroscopic method for assessing the content of non-metallic inclusions in forged or rolled steel products is used for determination non-metallic inclusions visible to the naked eye or with aid of a magnifying with magnification of not more than 10 times. Only inclusions equal to or greater than 1 mm long are taken into consideration. In this paper is given procedure for blue fracture test method applied on bar diameter ϕ 60 mm bearing steel 100Cr6. [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.)