Assessments and comparison of Inconel 625 and Inconel 718 alloys from overcut in micro ECM

Purpose In the current exploration, the machinability of three different nickel-based super-alloy materials (Inconel 625, Inconel 718 and Nimonic 90) was experimentally investigated by using a die-sinking electrical discharge machining (EDM). The effect of changing important input process parameters such as pulse on time (Ton), off time (Toff), peak current (Ip) and tool rotation (TR) was investigated to get optimum machining characteristics such as material removal rate, roughness, electrode wear rate and overcut. Design/methodology/approach Experimentation has been performed by using Taguchi L9 orthogonal design. An integrated route of fuzzy and grey relational analysis approach with Taguchi’s philosophy has been intended for the simultaneous optimization of machining output parameters. Findings The most approbatory factors for machining setting have been attained as: (Ton = 100 µs, Toff = 25 µs, Ip = 14 A, TR = 725 rpm) for machining of Inconel 625 and Inconel 718; and (Ton = 100 µs, Toff = 75 µs, Ip = 14 A, TR = 925 rpm) for machining of the Nimonic 90 material. Peak current has been observed as an overall influencing factor to achieve better machining process. Microstructural study through SEM has also been carried out to figure out the surface morphology for the EDMed Ni-based super alloys. Originality/value The proposed machining variables and methodology has never been presented for Nimonic 90 alloy on die-sinking EDM.

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Research on Mechanical Properties of Thin Sheets Blanks Made of Creep-Resisting Nickel Superalloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.212.259 ◽

2013 ◽

Vol 212 ◽

pp. 259-262

Author(s):

Monika Hyrcza-Michalska

Keyword(s):

Mechanical Properties ◽

Inconel 718 ◽

Nickel Alloys ◽

Thin Sheet ◽

High Strength ◽

Inconel 625 ◽

Thin Sheets ◽

Inconel 718 Alloy ◽

Mechanical Working ◽

Inconel Alloys

Mechanical working manufacturing methods of nickel alloys used conventionally strips and blanks need to solve many problems concerning high strength material forming which is characteristic limited plasticity. The production pressed elements of vehicle constructions and aircraft engine elements requires the high quality drawpieces since these are essential for safety. They are also the main structural components. Conventional methods of mechanical working such as pressing can be used in quantity production of the above mentioned elements and their production can also be cost-effective. Forming nickel alloys generates a lot of technological wastes resulting from back-springing effects determining the most appropriate pressure in the process of pressing. Failure holes in the process of bulging as well as cracking of drawpieces in the process of deep drawing. The heterogeneous mechanical properties distribution on thin sheet blanks made of Inconel alloy, which is different than material quality certificate shows, produces also a lot of manufacturing problems. These problems are usually solved by production engineers in the following way: dividing the production of ready drawpieces into a bigger number of simple blank profiling operations, shallow pressing, using a rubber punch for pressing or hydroforming. Complex drawpieces shapes are quite often made of several parts which are next welded. In the case of presented tube a tubular diffuser made of Inconel 718 alloy blank and cone made of Inconel 625. However the process of forming high strength materials like nickel alloys requires the application bigger forming forces than in the same kind of conventional formable steel processes. Tools get jammed quite often in the process and high force presses of 10 MN or more need to be used so is very expensive. The aspect of cold mechanical forming discussed materials has been a particular interest. The researches based on precise evaluation mechanical properties and technological plasticity of the selected materials in basic mechanical and technological tests as well as in FEM numerical simulation (finite elements method). The material models applied to simulation contain the pointed out experimentally the mechanical characteristics of Inconel alloys. The thin sheets blanks made of 0,9 mm thick Inconel 718 alloy and 0,45 mm thick Inconel 625 alloy blanks have been examined. The possibilities of using numerical simulations for solving the problems of selecting or modifying the pressing technology and hydroforming that type materials as well as forecasting the results of forming processes have been also presented. The evaluation of drawability of thin sheets blanks made of Inconel 718 and 625 alloys has also been discussed in the paper.

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Microstructure Analysis of Hybrid Laser Powder Bed Fusion and TIG Welding of Ni-based Superalloys

10.31224/osf.io/bz29t ◽

2020 ◽

Author(s):

Omar Fergani ◽

Katharina Eissing ◽

Teresa Perez Prado ◽

Ole Geisen

Keyword(s):

Inconel 718 ◽

Welding Process ◽

Positive Outcome ◽

Tig Welding ◽

Inconel 625 ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Heat Treated ◽

Weld Parameters

The industrial use of laser powder-bed fusion (L-PBF) in turbomachinery is gaining momentum renderingthe inspection and quali?cation of certain post-processing steps necessary. This includes fusiontechniques that allow to print multiple parts separately to take advantage of e.g. various print orientationsand join them subsequently. The main motivation of this study is to validate the tungsten inertgas (TIG) welding process of L-PBF manufactured parts using industrial speci?cations relevant for gasturbines to pave the way for the industrial production of modular build setups. For this, two commonlyused nickel-based super alloys for high-temperature applications, Inconel 718 and Inconel 625 are chosen.Since their defect-free printability has been established widely, we focus on the suitability to be joined usingTIG welding. The process is evaluated performing microstructural examination and mechanical testsin as-built as well as heat-treated samples. The welds are assessed by applying a general weld quali?cationapproach used at Siemens Gas and Power. It was found that both materials can be joined via TIGwelding using standard weld parameters causing minimal defects. A solution annealing heat treatmentbefore welding is not necessary for a positive outcome, but still recommended for Inconel 718.

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THE STRUCTURE AND COEFFICIENT OF FRICTION OF WELDED NICKEL ALLOYS INCONEL 625 AND INCONEL 718

Tribologia ◽

10.5604/01.3001.0012.7660 ◽

2018 ◽

Vol 281 (5) ◽

pp. 109-115

Author(s):

Katarzyna STRZELCZAK ◽

Agata DUDEK

Keyword(s):

Heat Treatment ◽

Electron Beam ◽

Coefficient Of Friction ◽

Inconel 718 ◽

Nickel Alloys ◽

Precipitation Hardening ◽

Electron Beam Welding ◽

Stress Gradient ◽

Test Method ◽

Inconel 625

In this study, the coefficients of friction for three series of welded nickel alloy joints, subjected to different heat treatments (lack of heat treatment, solution heat treatment, precipitation hardening), were determined. Heat treatment of the prepared samples was aimed at eliminating the structural and stress gradient, because the electron beam welding technique is dedicated for constructions with very high quality and strength requirements. Given the nature of the electron beam process, the authors are aware that the obtained weld’s structures are characterized by different properties from parent materials, and also from structures melted under equilibrium conditions. The scientific aim of the presented work is to determine the influence of heat treatment on the microstructure, mechanical properties, and performance of dissimilar joints of nickel alloys Inconel 625 and Inconel 718. In order to determine the coefficient of friction for samples, the scratch test method was used. As a result of the research, it was proved that subjecting the welds to the precipitation hardening has a significant effect on abrasion resistance.

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