Main Micro-Jet Cooling Gases for Steel Welding

Welding by the submerged arc (Eng. Submerged Arc Welding; SAW) method refers to melting the edges of the joint's elements and the material of the melting electrode by the heat of an electric arc under a layer of granular flux. A source of the heat is an electric arc, which is arcing in a gaseous Arch. Metall. Mater., Vol. 61 (2016) The article presents an analysis of properties of welded joints of fine-grained steel of P460NH type used more and more often in the modern constructions. A process of examining a technology of welding has been carried out on the thick-walled butt joints of sheet metal by two methods of welding namely MAG -135 and SAW -121. The article deals with a topic of optimizing a process of welding thick-walled welded joints of fine-grained steel due to their mechanicalproperties and efficiency.

Section: Materials Used For Examinationsmentioning

confidence: 99%

An Analysis of the Joints’ Properties of Fine-Grained Steel Welded by the MAG and SAW Methods

Krawczyk¹

2016

“…The outcome of correct execution of the experiment design are the output quantities, called "resultant factors". It has been found on the basis of an analysis of professional literature and the authors' own research [13][14][15][16][17][18][19] that the operational factors that have a significant influence on durability of the rail include the load, skid and speed [20][21][22][23][24][25][26][27].…”

Section: Testing Conditions and Proceduresmentioning

confidence: 99%

Quantitative and Qualitative Comparison of Tribological Properties of Railway Rails with and without Heat Treatment

Bąkowski¹,

Piwnik²

2016

Self Cite

The changes occurring in the structure of materials during their work are extremely significant from the point of view of extending the life of the railway track material. During the operation of rails, fatigue wear occurs, whose effects are dangerous. In order to prevent fatigue wear, it is necessary to get to know the mechanism of its formation and, in particular, the changes it causes in materials [1].The elements of a railway track structure which directly come into contact with the wheels of railway vehicles are its rails. Their condition determines to a large extent the safety of railway transport. The condition of rails is determined by, inter alia, the wear processes and the selection of materials from which the rails are made, appropriate to the operating conditions [2]. The application of inappropriate materials for rails increases their wear and, consequently, lowers safety on railroads, while increasing the costs incurred by railway operators in connection with repairs [3].Presently, the largest problem is to keep balance between abrasive wear (vertical and side wear -occurring in the rails) and fatigue wear, the latter appearing in the form of contactfatigue damage, leading to chipping of the surface, or even to cross cracks [4].Due to a wide scope of the problem raised, the focus is on the question of durability and reliability of the currently used railway rails.A quantitative analysis of products generated in the rolling-sliding contact and their computer processing are important tools in the examination of wear products. They allow us to identify the wear mechanism quickly and to evaluate the degree of the tribological system wear.To sum up, the aim of this study is an attempt to explain the cause-effect relation between the influence of operational parameters and the wear of the wheel-rail contact zone, where fatigue processes are initiated. This way, getting to know and defining the nature of the phenomenon enables determining of the element's work reliability (appropriate selection of material, depending on the operational conditions). To achieve the aims planned, laboratory tests were made, in which the most significant operational parameters occurring in the real object and influencing the durability of the wheel-rail couple were reflected [5]. For this purpose, a dimensional analysis was applied, which reflects the real conditions presnt in this pivotal place, i.e. the contact point. A specific feature of laboratory tests is that it is possible to better control the direct influence of one selected factor than in the real operational conditions [6]. Material and research methodPearlitic steels are the materials most often used for producing rails. Tests were made using specimens of heat treated rails (HT) and rails without heat treatment (WHT), made of pearlitic steel R260 with a chemical composition and mechanical properties compliant with the UIC 860 standard [8]. In the tests, products of wear generated in the friction couple in laboratory conditions, from both, heat treated rails (WDHT...

“…For this purpose, the authors decided to join presented in publications two methods: micro-jets and HVOF [7][8][9][10]. It was assumed that suitably selected micro-injectors and processing parameters provide adequate heat dissipation of the applied surface and thus reduce thermal stresses].…”

Section: The Idea Of Hybrid Spraying Methods Combinedmentioning

confidence: 99%

New Technological Concept for Thermal Spray Protective Coatings

Szczucka-Lasota

Piwnik

2017

Self Cite

Thermally spraying with micro-jet cooling is an innovate technology. It is possible to get fine dispersive structure of coatings during the shorter time in comparable to the classical high velocity oxygen fuel process (HVOF). It corresponds with good corrosion-erosion properties of structure. In the paper the parameters of the spraying with micro-jet cooling process are presented. The selected properties of coatings obtained by hybrid method are presented. The results of wear tests for hybrid and HVOF coating are compared. Results of investigation are very optimistic. The presented technology should be adapted to the actual production of protective coating for machines and construction working in wear conditions.