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Microstructure and Properties of Dissimilar Joints of AISI 430 Steel with Inconel 625 Obtained by Electron Beam Welding

Dziekońska Małgorzata, Jonda Ewa, Sroka Marek, Węglowski Marek Stanisław, Jung Tymoteusz

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 4

232--242

EN

Electron Beam Welding (EBM) is a high-energy density fusion process where joint is bombarded to be welded with strongly focused beam of electrons. This method is often used for advanced materials and complex, critical parts, like turbine rotors, but it can also be used for many simpler processes involving large production runs. It is very suitable for butt welding materials of different thicknesses. The aim of this work was to study the microstructure, hardness, and electrochemical corrosion behavior between the dissimilar welds were investigated. Electron Beam Welding of dissimilar steel alloys Inconel 625 and AISI 430 was studied. In welding process there was used only welded materials without filling material. Results showed the microstructure of the weld solidified in dendritic morphology. The microstructure of fusion zone showed that dendrites grew in different directions for each grain. The dendrites and columnar grains are mainly exposed to the fusion boundary with some equiaxed grains. The hardness of the overall joint was non-uniform. The highest hardness of the HAZ/Inconel 625 (the heat-affected zone) was 258 HV, and the lowest weld zone hardness was 178 HV. The decrease in weld hardness may be due to the linear welding energy, which led to grain growth and excessive cooling. HAZ/AISI 430 steel has the lowest current density and the highest corrosion potential. Steel has a more negative corrosion potential and a lower corrosion current density than joints, likely due to higher levels of chromium. In this study, a metallographic investigation of the joints revealed no defects such as microcracks or pores. The melting temperatures of the two materials were quite different, but with the help of gravity, stainless steel acts as a permanent joint, like a rivet.

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Prediction and Optimization of Magnetic Properties of Laser Welded AISI 430 Stainless Steels

Mostaan H., Rafiei M.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 4

1673--1682

EN

The AISI 430 stainless steel with ferritic structure is a low cost material for replacing austenitic stainless steel because of its higher yield strength, higher ductility and also better polarisation resistance in harsh environments. The applications of AISI 430 stainless steel are limited due to insignificant ductility and some undesirable changes of magnetic properties of its weld area with different microstructures. In this research, a study has been done to explore the effects of parameters of laser welding process, namely, welding speed, laser lamping current, and pulse duration, on the coercivity of laser welded AISI 430 stainless steel. Vibrating sample magnetometery has been used used to measure the values of magnetic properties. Observation of microstructural changes and also texture analysis were implemented in order to elucidate the change mechanism of magnetic properties in the welded sections. The results indicated that the laser welded samples undergo a considerable change in magnetic properties. These changes were attributed to the significant grain growth which these grains are ideally oriented in the easiest direction of magnetization and also formation of some non-magnetic phases. The main effects of the above-mentioned factors and the interaction effects with other factors were evaluated quantitatively. The analysis considered the effect of lamping current (175-200 A), pulse duration (10-20 ms) and travel speed (2-10 mm/min) on the coercivity of laser welded samples.

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Microstructure and Wear Properties of FeCrC, FeW and Feti Modified Iron Based Alloy Coating Deposited by PTA Process on AISI 430 Steel

Teker T, Karataş S., Yilmaz S. O.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 3

925--933

EN

The plasma transferred arc (PTA) process was used for developing wear resistance of AISI 430 steel substrate. Appropriate quantities of FeCrC, FeW and FeTi powders were combined to create conditions that synthesized M7C3 particles into reinforced Fe-based composite surface coating. The phase transformations on new created coated surfaces were comprehensively examined by using a combination of scanning electron microscopy (SEM), microanalysis by energy dispersive spectrometry (EDS), X-Ray diffraction (XRD), microhardness and abrasive wear tests. The microstructure studies of the superficial layers of the coating revealed presence of a mixture of the dendritic phase structure of austenite (γ) and fine eutectic M7C3 carbides. The results show that; the concentrations of the elements (Cr, W, Ti) added as ferroalloys, the size of dendrites formed in the coated surface, the change of hardness of the coated surfaces, the carbide volume rate and thickness of the coating changed by the variation of the processing parameters (ratio of reinforcement particulates and heat input).

PL

Technika PTA została zastosowana jest do podwyższania odporności na zużycie podłoży ze stali AISI 430. Odpowiednie ilości proszków FeCrC, FeW i FeTi połączono w celu stworzenia warunków, w których syntetyzowane są cząsteczki M7C3 zbrojące powłoki kompozytowe na bazie Fe. Przemiany fazowe w nowo utworzonych powlokach zostały szczegółowo zbadane za pomocą kombinacji skaningowej mikroskopii elektronowej (SEM), mikroanalizy spektrometrią dyspersji energii (EDS), dyfrakcji rentgenowskiej (XRD), mikrotwardości i testów ścierania. Badania mikrostruktury wierzchnich warstw powłoki wykazały obecność mieszaniny struktury dendrytycznej austenitu (γ) i drobnych eutektycznych węglików M7C3. Wyniki pokazują, że: stężenie pierwiastków (Cr, W, Ti) dodanych jako żelazostopów, wielkość dendrytów utworzonych w powłoce, zmiany twardości powłoki, szybkość objętościowa węglików i grubość powłoki zmieniają się ze zmianą parametrów procesu (stosunek cząstek wzmacniających i mocy cieplnej).

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Fusion and friction stir welding of X6Cr17 stainless steel

Meran C., Bilgin M.B.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

403--409

EN

Purpose: The σ-phase is the most serious of these secondary phases due to its impact on the mechanical properties, corrosion resistance or weldability of stainless steels among other properties. The purpose of this study is getting free σ-phase welding joints by using very novel welding method such a called friction stir welding. Design/methodology/approach: Both of fusion welding methods (MIG and TIG) and friction stir welding method were used to compare microstructure analysis of AISI 430 ferritic stainless steels. After welding, the formation of σ-phase was investigated by mechanical, chemical and micro structure analyses of welded joints. Findings: As a result, the formation of σ-phase have not been observed in FSW processes while compared to traditional fusion welding processes. Not only σ-phase have not been observed in metallurgical investigations but also micro hardness of all specimen have not been over 400HV on friction stir welded joints. Research limitations/implications: It is very difficult to be constant vertical force during friction stir welding. For keeping constant this force, hydraulic controlled welding machines could be used in further researches. Practical implications: This paper and its’ results shown that the friction stir welding could be used for joining of ferritic stainless steels, when you select suitable welding parameters. Originality/value: This study was performed in the frame of the Pamukkale University Scientific Research Projects Coordination Unit project no 2009FBE022 “The research of the factors affecting the friction stir weldability of ferritic stainless steels”.