Runchev, Dobre
Preferred name
Runchev, Dobre
Official Name
Runchev, Dobre
Main Affiliation
Email
dobre.runchev@mf.edu.mk
12 results
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Item type:Publication, Comparison of weld quality of unalloyed boiler steels obtained by changing arc process for the root pass(Mechanical Engineering Faculty in Slavonski Brod, 2017-10-25); ; Gjorgjevikj, SlagjanThis paper considers the effect of applied welding process over the weldment quality. Unalloyed boiler steels such as P265GH (EN) and S355 J2 (+N) (EN) are used as base material respectively. Welding is performed as multipass with SMAW (111), GMAW (131 and 135) and SAW (121). Four different groups of welded speciments are created, depending of the root pass. In the first, second and third group, the root pass is done with 111, 131 and 135 and filling passes with 121, while the fourth group is completely performed by 121. All welds are inspected radiographically and metallographically before submited to further evaluation. Quality assessment of weldments is determined through classical mechanical investigations such as tensile and bending test, Vickers hardness along the weldment and Charpy impact test. Attained results indicate that hybrid arc welding guarantees safer performance and general quality of welded joint. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Welding tehnology for steel P460NL2(Centre for Evaluation in Education and Science (CEON/CEES), 2022); <jats:p>This paper presents the development of welding technology for P460NL2 steel with a thickness of 30 mm. The technology was developed for the purpose of producing housings in which the device PIG-Pipeline Inspection/Intervention Gauge intended for testing and maintenance of pipelines is installed. In this particular case, the housings were intended for cleaning pipelines for the transport of acid-aggressive gases. The material was selected in accordance with NACE MR0175/ISO 15156 and ASME BPVC IKS standards. The welding technology is made for butt joint, root pass with GMAW, and other layers filled with SAW. Preheating and heat treatment after welding were performed to restore the structure. Standard tests are conducted such as: metallography, hardness test, tensile test and toughness, and the results are presented and commented in this paper. In conclusion, the welding technology gives satisfactory results, but, in terms of meeting the specifics of the NACE MR0103 and MR0175 standards, it shows increased hardness in the transition zone, in the HAZ.</jats:p> - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of Edge Surface Quality on Hybrid Laser Arc Welding of Structural Steel S355J2(2024); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of cutting parameters on the quality of the cut surfaces of steels with a laser beam(Department for Production Engineering, Faculty of Technical Sciences, Novi Sad, Serbia., 2019); ; Ivanova, IrenaThe main objective of the research covered in this paper is to present results for the quality of surfaces thermally cut with a laser beam. The variety of steel materials used as samples on which laser cutting is performed are the following Č.0146 (1.0330), Č.0147 (1.0333), Č.2131 (1.5024), SS Ferbec CR, HARDOX 450 and HARDOX 550. Thermal cutting is carried out with a CNC controlled Fiber laser BAYKAL type BLS–F–1530. The quality of the cut surface is analyzed based on varying the power of the laser beam, changing cutting speed and the type of additional gas (oxygen, air and nitrogen). By visual inspection, measuring the roughness of the cut surface and measuring the width of the intersection, it is determined the influence of the factors like type of the base material, type of gases, the power of the laser beam and the cutting speed, in accordance with the standards DIN EN ISO 9013-2002 and the JUS C.T3.022. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of Cr content in steel 12X1MF on exploitation life of superheater pipes(Mechanical Engineering Faculty in Slavonski Brod, 2019-10-16); The most widely-used material for tubes in ex soviet power plants is steel 12X1MF. Until today, 12X1MF has proven to be a reliable material for use in plants that operate in conditions of creep (temperature about 540-550 °C and pressure about 14-15 MPa). The microstructure of steel in the initial state depends on the heat treatment that it has undergone. Generally, low alloy CrMo(V) creep-resistant steels applied for construction of energy plants have initial ferritic-bainitic microstructure with fine dispersion of globular carbides precipitated in the ferritic matrix and at grain boundaries. Chromium has a positive effect on the heat resistance (resistance to oxidation) of the steel as well as hardenability and indirectly affects the creep resistance. Chromium should be in a solid solution. After complete heat treatment cycle, chromium carbides in 12Х1MF should not exceed 10-20% of the total Cr+Mo+V carbide content. The effect of chromium in ferritic creep-resistant steels is complex. This paper deals with the case of a superheater pipe failure (fish-mouth rupture) which is partly caused by the fact that the pipe has a lower Cr content than that provided for 12Х1MF steel. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, INFLUENCE OF THE METAL CORED AND FLUX CORED WIRE ON THE STRUCTURAL STEEL WELDED JOINTS(2023); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Welding technology of martensitic steel P91 and austenitic steel 304H – State of the art(INTERNATIONAL SCIENTIFIC JOURNAL "MACHINES. TECHNOLOGIES. MATERIALS", 2023); Many industries nowadays with the development of technology require joints between different types of steel due to its various benefits such as production of lightweight machine parts, production of less expensive components with acceptable properties, high strength, acceptable corrosion resistance. One of the dissimilar welding challenges is the joint between martensitic steel P91 and austenitic steel 304H due to the dissimilarities in their chemical, physical and metallurgical properties. In this paper is going to be analysed the best way of joining the two different types of steel, the proper welding technique, the choice of filler material which according to carbon content can match only to one of the steels. At the end is discussed if the welding performance can meet the requirements of high-quality weld. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Welding technology of martensitic steel P91 and austenitic steel 304H – State of the art(INTERNATIONAL SCIENTIFIC JOURNAL "MACHINES, TECHNOLOGIES, MATERIALS" Issue 1/2023, 2023); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Welding technology of martensitic steel P91 and austenitic steel 304H – State of the art(SCIENTIFIC TECHNICAL UNION OF MECHANICAL ENGINEERING INDUSTRY-4.0, 2023); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of Edge Surface Quality on Hybrid Laser Arc Welding of Structural Steel S355J2(2024);