In this work thermal fatigue resistance of 1.7C, 11.2Cr, 2.0Ni, 1.2Mo steel for hot working rolls was studied using our newly developed test rig with specially prepared test samples. Tests were carried out in temperature range between 500–700 C whereas relevant characteristics related to cracks after 200, 500, 1000, and 2500 cycles were obtained. Average length of all cracks, their density, average length of five longest cracks, and relevant microstructural characteristics of tested specimens were determined. It was found that initiation of cracks is strongly related to the cracking and spalling of carbides at specimens surface layer and that cracks growth is related to the characteristics of carbides. For comparison also results for Indefinite Chilled Double Poured roll cast iron are given. Based on obtained results, possible improvements of thermal fatigue resistance of these two materials are discussed.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 1716575Dimension (natural or ornamental) stone blocks contain many discontinuities and cracks, those characteristics are reflected on slab excavation index. Dimension stone blocks compactness was previously controlled through various methods that were based on experience and visual observance of stone blocks. With the development of technology, the ultrasonic pulse method is frequently used for the examination of stone samples compactness. The method is based on the passage of longitudinal waves through the stone block without damaging the material during measurement. High differences in ultrasonic velocity show irregularities in the material. Using the tomography method and with an analysis of acquired data, the stone block compactness can be determined. The technique of data acquisition and the use of various devices allow a good overview of the stone block interior. With an increased number of Lipica limestone blocks (Lipica Unito, Lipica Fiorito, Repen, and Kopriva) in-situ measurements, a suitable compactness classification is prepared that helps reduce processing costs and increases the quality of stone slates and other stone products and will be introduced in the article.
F.06 Development of a new product
COBISS.SI-ID: 1763679In the Murska Sobota area, Pomgrad has the mining right to acquire sand. For the purposes of analyzing the effects of mining on groundwater, we developed a model of the groundwater flow and the transport of contaminant. The model is build using the ModFlow Flex software package.
F.17 Transfer of existing technologies, know-how, methods and procedures into practice
COBISS.SI-ID: 1798239Bioterme Mala Nedelja uses geothermal water from the Mura formation. This groundwater has about 60 st. C. Using the groundwater model of water flow and heat transfer, a program for observing the thermal aquifer in the Mura formation was developed.
F.16 Improvements to an existing information system/databases
COBISS.SI-ID: 1794655IOC Metlika is located in the Karst region. After the drainage was completed, the surface was subsiding. The subsiding occurred due to the rinsing of the filter in the karst cracks. With the help of a georadar, we discovered the cracked zones and proposed remedial measures.
F.17 Transfer of existing technologies, know-how, methods and procedures into practice
COBISS.SI-ID: 1797727