Difference Between Electroslag Welding And Electrogas Welding Pdf
File Name: difference between electroslag welding and electrogas welding .zip
- Electrogas Welding
- Electroslag welding
- Electrogas welding
- Welding Technology | Electro Gas Welding (EGW)
Fabrication of electroslag welded Magnox fuel transport flasks. The high weld metal deposition rate of the electroslag welding process offers an attractive method of fabricating nuclear fuel transport flasks from mm The paper describes pre-production trials carried out on full scale corner-section joints to establish that the weld metal meets the exacting mechanical property requirements for the Nuclear Industry.
The paper presents results obtained on welds produced using two base metal compositions and two wires, one recommended for submerged-arc and the other for electroslag welding processes. Details of mechanical tests and metallographic examinations are given which led to the selection of the latter type of wire.
It was found that while the weld metal deposited by this process may be sensitive to cracking, this can be avoided by careful selection of welding consumables and sound joints can be obtained under production conditions. Electroslag welding of rotor steels produced with vacuum-carbon reduction. Metallurgical processes of electroslag welding of rotor steels, melted with vacuum-carbon deoxidation, have been considered.
It is established, that during electroslag welding of steels with carbon content 0. A fitness-for-purpose evaluation of fracture critical electro-slag welds. A fitness-for-purpose evaluation was performed on the electro-slag flange welds of the West Fremont bridge approach : superstructures, per the request of FHWA. This evaluation required gathering knowledge of the material properties, fabrication : def The electrogas and electroslag multipass high speed welding of nuclear pressure vessel steels.
High-speed electroslag and electrogas welding of 15 Mn Ni63 steel plates to achieve high strength and toughness joints for reactor pressure vessels are described. Mechanical testing of overheating-resistant, brittle fracture resistant low alloy steels is discussed. Czechoslovak flux VUZ-4F and the optimized welding mode were completely proven.
The bending deformation resulted in breaking the coarse-grain casting structure in the entire cross-section, it was, however, only acting in a narrow band corresponding to the largest curvature. At the same time, the heat affected zone decayed. Following heat treatment, especially forming, the delta ferrite content in the weld metal decreased, the mechanical properties of the weld metal and the welded joint following welding and heat treatment showed a relatively large scatter. Forming reduced the scatter and improved plastic properties.
The welded joint showed equal properties as the base material of the weldment. Jorge, Jorge C. The use of superaustenitic stainless steels SASS as an overlay replacement for nickel-based alloys can be an interesting alternative for the oil and gas industries, due to its lower cost, when compared to superalloys. Usually, the deposition is made with several welding passes by using conventional arc welding processes, such as gas tungsten arc welding GTAW or gas metal arc welding GMAW processes.
In this respect, electro-slag welding ESW , which promotes high heat inputs and low dilution of the welds , can also be attractive for this application, as it provides a higher productivity, once only one layer is needed for the deposition of the minimum thickness required. Both as- welded and heat-treated conditions were evaluated and compared.
A multipass welding by GMAW process with three layers and 48 passes was performed on For both processes, the austenitic microstructure of the weld deposits was characterized by optical microscopy and scanning electron microscopy with electron backscatter diffraction. A low proportion of secondary phases were observed in all conditions, and the PWHT did not promote significant changes on the hardness profile. Martensite for GMAW process and bainite for ESW process were the microstructural constituents observed at the coarse grain heat-affected zone, due to the different cooling rates.
For ESW process, no evidences of partially diluted zones were found. As a consequence of the microstructural. Reliability and durability of the 12Kh1MF steel tubes of electroslag remelting and their welded joints. Results of investigating the positive effect of electrolag remelting ESR on the properties of the base metal and welded joint of the 12Kh1MF steel steam pipes with the aim of increasing their durability up to 20, hrs, are presented.
To estimate the quality and properties of tube billet metal, microstructure, content and nature of nonmetallic inclusions, content of gases, austenite grain size, austenite transformations during continuous cooling, metal ductility, mechanical properties at different temperatures and heat resisting properties, have been investigated. It is established, that the base metal in tubes of electroslag remelting possess higher heat resistance, while welded joints besides, have high deformability and resistance to brittle fracture.
Using cast-on electroslag technology for manufacturing nuclear power station equipment. An application of a new electroslag cast-on process for manufacturing nuclear power station equipment is described. Welding technologies for nuclear machinery and equipment. The main welding methods applied to nuclear machinery and equipment are shielded metal arc welding , submerged arc welding , MAG welding and TIG welding. But in the last 10 years, in order to improve the reliability required for the welding of nuclear machinery and equipment, the welding technologies aiming at the reduction of heat input, the decrease of the number of welding pass and the automatic control of welding factors have been applied for the main purpose of bettering the quality and excluding human errors.
The merits and the technology of narrow gap, pulsed MAG welding and melt-through welding are explained. For the longitudinal welding of active metal sheet products, plasma key-hole welding is applied. Since the concentration of its arc is good, high speed welding with low heat input can be done.
For the stainless steel cladding by welding , electroslag welding has become to be employed in place of conventional submerged arc welding. Arc is not generated in the electroslag welding , and the penetration into base metal is small. Electroslag remelting of cobalt-base superalloys. The alloys were electroslag remelted ESR in an inert gas using single-phase a.
Comparisons of ESR ingots with vacuum-arc remelted VAR ones were made on the basis of composition, surface condition, macrostructure, hardness, microstructure, room- and elevated-temperature tensile strength and ductility, and high-temperature stress-rupture strength. Minimal differences in non-metallic inclusions, chemical refinement except perhaps for reduced S and P contents , hardness, and tensile properties were observed in ESR ingots as compared with VAR material.
Microstructures of VAR ingots and of ESR ingots prepared with the quaternary flux contained larger intergranular eutectic lamellae than ESR material obtained using ternary fluxes. Modern methods of overlay welding for corrosion protection of power generating equipment. Methods for overlay welding of inner surfaces of power equipment for corrosion protection are analysed. Various methods of electroslag overlay welding by a band electrode overlay welding by two-electrode bands by a wide band with magnetic control, by an electrode band with high melting velocity are marked to be the most perspective for cladding of NPP vessel equipment.
Recent progress of welding technology applied for nuclear components. More than 30 years have been passed since the first nuclear power plant was in operation. Various needs for welding technology have been emerged and the technology has been developed. Welding techniques are introduced in detail. Applications of arc welding , gas tungsten arc welding , electroslag welding , electron beam welding are explained.
In order to avoid stress corrosion cracking, water jet and laser peening techniques are used. The curriculum guide for welding instruction contains 16 units presented in six sections. Each unit is divided into the following areas, each of which is color coded: terminal objectives, specific objectives, suggested activities, and instructional materials; information sheet; transparency masters; assignment sheet; test; and test answers.
Thermal-deformation effect of welding on A 1 reactor pressure vessel weld joints properties and state of stress. The methods are compared of electroslag welding and of arc welding with a view to their possible application in welding the Bohunice A-1 reactor pressure vessel. Considered are the thermal deformation effects of welding on the physical properties and the stress present in welded joints.
The deformation effect of welding on the residual surface and triaxial stress, the specific stored energy, the initiation temperature of brittle crack and the critical size of the initiation defect corresponding to the thermal deformation effect of welding were determined. It was found that for electroslag welding , there is a low probability of crack formation in the joints, a low level of residual stress and a low level of specific stored energy in a relatively wide joint zone.
For arc welding there is a considerable probability of defect formation in the vicinity of the sharp boundary of the joint, a high level of the triaxial state of stress in the tensile region, and a high level of specific stored energy concentrated in the narrow zone of weld joints. Directory of Open Access Journals Sweden. Full Text Available The article presents an analysis of properties of welded joints of thick-grained steel of PNH 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 submerged arc welding SAW - and electroslag ESW - The article deals with a topic of optimizing a process of welding thick-walled welded joints of fine-grained steel due to their mechanical properties and efficiency.
Effects of heat input on the pitting resistance of Inconel welds by overlay welding. The objective of this study was to establish the relationship between the dilution ratio of the weld zone and pitting resistance depending on the heat input to welding of the Inconel alloy.
Each specimen was produced by electroslag welding using Inconel as the filler metal. In the weld zone of each specimen, dendrite grains were observed near the fusion line and equiaxed grains were observed on the surface.
It was also observed that a melted zone with a high Fe content was formed around the fusion line, which became wider as the welding heat input increased. In order to evaluate the pitting resistance, potentiodynamic polarization tests and CPT tests were conducted.
The results of these tests confirmed that there is no difference between the pitting resistances of each specimen, as the structures of the surfaces were identical despite the effect of the differences in the welding heat input for each specimen and the minor dilution effect on the surface. Numerical investigations of the electroslag remelting process for alloy In this dissertation the development of a simulation strategy is presented, which enables a detailed description of relevant regions to appropriately model the electroslag remelting process.
One of the challenges is to ensure a sufficient efficiency of the numerical model so that it can be used to perform extensive parametric studies. Therefore the electroslag remelting process is divided into a droplet simulation and models that account for the fluid flow in the slag and fluid flow and solidification in the metal pool.
The droplet simulation considers the multiphase flow and the interaction of fluid flow and magneto hydrodynamics to simulate the behavior of the metal droplets passing through the slag layer. The Lorentz force is the main driving force for the fluid flow established in the slag region, which causes the liquid metal film on the electrode's bottom surface to be transported to the centerline.
Therefore it was found that no metal droplets detach near the electrode's edge. Instead they accumulate at a certain characteristic radius. Between this radius and the centerline metal droplets form and detach homogeneously. The fluid flow in the slag region is directed to the centerline near the electrode's bottom surface, points downwards on the centerline, moves outwards near the phase boundary to the metal pool and is directed upwards at the surface of the copper mold.
In the case of the smaller scale IME remelting plant, metal droplets only occur on the centerline. The steady state simulation of the electroslag remelting process developed during this work introduces a static phase boundary, which separates the slag and the metal region. The formulation of the static phase boundary drastically reduced the time required until convergence is achieved.
The simulation model has been extensively validated by comparing the numerical results to. Welding of components of primary circuits of nuclear reactors in FRG. Welding materials and methods, surfacing and soldering, applied when assembling nuclear reactors in the Federal Republic of Germany, are considered. It is noted that reactor vessel flux two-pass surfacing is mainly carried out, using the band electrode.
The austenitic steel serves as filler material. Vessels are welded using electroslag flux method and nonconsumable electrodes. Tube plates claddina and tube welding during steam generator production are made by flux surfacing and inert gas shielded using nonconsumable electrode.
Electroslag-welding is a process providing one of the highest weld deposition rates and is therefore most cost-effective for suitable applications.. Its unique capability permits to weld in one pass groove joint of two plates, thick 1 to 12 inches 25 to mm and more. It is mainly used in the shipbuilding and storage tank industries. It gives excellent slag removal and bead appearance also for Nb-alloyed strip electrodes. Electrogas welding is a development of electroslag welding and resembles it, in terms of arrangement and use.
Electro Gas Welding is an arc welding process that uses an arc between a continuous filler metal electrode and the weld pool, employing vertical position welding with backing to confine the molten weld metal. Electro gas welding is very much similar to electro slag welding except that an inert gas such as carbon di oxide is used to shield the weld from oxidation and there is a continuous arc as in the case of submerged arc welding to provide the heat for heating the weld pool. Again the flux instead of being supplied to the weld zone through a hopper is incorporated in electrode itself in the form of flux cored electrodes, or sometimes the process may be carried out without using the flux in which case there is no flux covering on the top of the molten metal pool. Electro gas welding process is used for welding low and medium carbon steels, alloy steels and austenite stainless steels.
Welding Technology | Electro Gas Welding (EGW)
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Electrogas welding EGW is a continuous vertical position arc welding process developed in , in which an arc is struck between a consumable electrode and the workpiece. A shielding gas is sometimes used, but pressure is not applied. A major difference between EGW and its cousin electroslag welding is that the arc in EGW is not extinguished, instead remains struck throughout the welding process. It is used to make square-groove welds for butt and t-joints , especially in the shipbuilding industry and in the construction of storage tanks. In EGW, the heat of the welding arc causes the electrode and workpieces to melt and flow into the cavity between the parts being welded. This molten metal solidifies from the bottom up, joining the parts being welded together. The weld area is protected from atmospheric contamination by a separate shielding gas , or by the gas produced by the disintegration of a flux-cored electrode wire.
Self-shielding electrodes eliminate the need for external shielding gas. A major difference between ESW and EGW is that the former relies on slag conduction to.
ESW is similar to electrogas welding , but the main difference is the arc starts in a different location. An electric arc is initially struck by wire that is fed into the desired weld location and then flux is added. Additional flux is added until the molten slag , reaching the tip of the electrode, extinguishes the arc.