• TECHNOLOGIES

    Analyze of welding arc parameters in shielded metal arc welding

    Machines. Technologies. Materials., Vol. 17 (2023), Issue 2, pg(s) 80-82

    Shielded metal arc welding is widely used in heavy industries in partly shipbuilding and ship repair. This method didn’t required special personal skills and equipment. Different scientists are analyzed welding parameters, mechanical characteristics and chemical composition in welding seam but interesting is to be investigated welding arc characteristics in different electrodes. The paper deal with analyze of welding arc parameters in shielded metal arc welding. For this purpose on mild steel plates are welded seams with different diameters of electrodes and different welding current. In welding process are measured welding arc burning time, length of electrodes melted part, welding machine voltage and weight of melted electrodes part. For analyze welding arc parameters are used response surface methodology method (RSM). Used RSM in the paper is 2k factorial design where k=2 factors. The influence of each to other factors of welding arc is presented by meta models.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    Application of hardfacing arc methods in Bulgarian ship repair SME

    Trans Motauto World, Vol. 7 (2022), Issue 2, pg(s) 50-52

    The paper deal with methods for hardfacing used in small and medium sized ship repair enterprise. The difference between welding and hardfacing are explained. In first part of the paper are analyzed disadvantages and advantages of arc hardfacing welding methods, materials and consumables in hardfacing. After that are described two case studies from ship repair industry. In ship repair SME with restricted resource some of hardfacing methods are not applicable. In this paper are described hardfacing methods which are applicable in this type of ship repair yard.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    Analysis of ship construction designed for restricted production facilities at SME

    Trans Motauto World, Vol. 6 (2021), Issue 4, pg(s) 123-126

    The paper presents the design and construction process of a series of four multipurpose ships for SME shipyard with some restrictions in production facilities. This process is based on software that is available free or the some tasks could be subcontracted by SME. The main dimensions are optimized by the system “Expert” and hull forms are generated by PolyCAD. Due to the restriction in the production facilities the ships are with the same breadth and for additional unification the depth is also equal. Three different hull structure topologies are evaluated by MARS2000 software and modeled by AVEVA Marine design software. The analysis includes evaluation of manhours for construction of parallel mid-body of the all variants. The analysis takes into account the restricted preassembly space and human recourse, lifting capacity of building crane, geometry of building slipway etc. Some conclusions for labor intensity and inf luence of series function are made based on the presented data.