Effect of electric parameters of arc surfacing using flux-cored wire on process stability and base metal penetration

Abstract

Effect of electric parameters of arc surfacing using self-shielding flux-cored wires on process stability and base metal penetration was investigated. The experiments were carried out with computer registration of electric parameters of surfacing. The results of oscillogram processing were used for plotting of Iw and Uw diagrams with outlined areas of stable process of surfacing, short circuits and arc extinctions. Coefficient of process instability γ was derived from received real parameters of arc surfacing using flux-cored wire. It is determined that voltage has the largest effect on stability indices and its rise improves process stability. Effect of modes of surfacing on penetration and portion of base metal in the deposited metal was investigated. 3D chart was plotted on estimation results. An area of optimum modes, providing sufficient stability of the process at minimum penetration and good formation of deposited beads, is outlined. K e y w o r d s : arc surfacing, flux-cored wire, stability of surfacing process, instability coefficient, base metal penetration, portion of base metalNecessary composition of the deposited metal in multilayer arc surfacing can be obtained only in the third or fourth layer [1] due to its mixing with the base metal. Five layers as minimum should be surfaced, if machining of part is necessary after surfacing. The problem becomes more complicated due to the fact that rise of thickness of the deposited layer promotes for growth of residual shearing stresses and, simultaneously, increases the possibility of appearance in the deposited layer of different type defects, which reduce its service properties, including fatigue life under cyclic loading [2,3]. Thus, one of the most important characteristics for surfacing is a portion of base metal (PBM) in the deposited metal proportional to base metal penetration other things equal. Reduction of the base metal penetration not only decreases consumption of expensive consumables, but improves quality and service properties of the parts to be surfaced.Aim of the present work is a study of effect of electric parameters of flux-cored arc surfacing, in particular, stability of these indices on characteristics of the base metal penetration.Consumables and equipment. Self-shielding flux-cored wire PP-AN130 was used for investigations. It provides for production of surfaced metal of tool steel 25Kh5FMS type. Gas-slagforming system of the flux-cored wire, which would provide the best welding-technological properties, was preliminary selected. Four selfshielding flux-cored wires PP-AN130 of 2 mm diameter having different systems of gas-slagforming components, namely СаO + TiO 2 + MgO + CaF 2 + Al 2 O 3 (wire with reference designation PP-AN130-1); СаO + MgO + CaF 2 + Al 2 O 3 (PP-AN130-2); СаO + CaF 2 + Al 2 O 3 (PP-AN130-3); СаO + CaF 2 + Al 2 O 3 + starch (PP-AN130-4), were manufactured for this purpose.Expert estimation (5 examiners) of the welding-technological properties of all four wire types (nature of metal transfer, slag coating of the ...

Energy approach in analysis of microplasma powder surfacing modes

“…Measurement, recording and mathematical treatment of electric parameters of the welding arc have been applied for a long time to study the features of arcing, regularities of the process of electrode metal transfer, as well as welding equipment testing [1][2][3][4][5][6][7][8][9][10].…”

“…Data acquisition systems [5][6][7][8][9][10] have become widely applied recently for recording, processing and analysis of process parameters of the welding arc. These systems allow:…”

“…At the present stage such systems are hightechnology tools for recording the main parameters of welding processes, which alongside their monitoring [8] and analysis of welding equipment quality [9], also allow optimization of technological control of the welding arc [10].…”

Computer information-and-measuring system for investigation of arc surfacing processes

“…It should provide the possibility of selection of the type of electrode material (solid or flux-cored wire, cold-rolled or flux-cored strip) and its sizes (diameter, cross section); surfacing method (submerged, open-arc or in shielding gases); presetting and maintaining the preset conditions and techniques of surfacing; marking of accidental or intentional deviations from the preset surfacing modes; memorization and subsequent use of optimum modes of surfacing the specific parts. The existing experience [1][2][3] shows that the modern level of development of computer science allows solving this problem.…”