scholarly journals The Phenomena and Criteria Determining the Cracking Susceptibility of Repair Padding Welds of the Inconel 713C Nickel Alloy

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 634
Author(s):  
Katarzyna Łyczkowska ◽  
Janusz Adamiec

The creep-resistant casting nickel alloys (e.g., Inconel 713C) belong to the group of difficult-to-weld materials that are using for precise element production; e.g., aircraft engines. In precision castings composed of these alloys, some surface defects can be observed, especially in the form of surface discontinuities. These defects disqualify the castings for use. In this paper, the results of technological tests of remelting and surfacing by the Tungsten Inert Gas method (TIG) in an argon shield and TecLine 8910 gas mixture are presented for stationary parts of aircraft engines cast from Inconel 713C alloy. Based on the results of metallographic studies, it was found that the main problem during remelting and pad welding of Inconel 713C castings was the appearance of hot microcracks. This type of defect was initiated in the partial melting zone, and propagated to the heat affected zone (HAZ) subsequently. The transvarestraint test was performed to determine the hot-cracking criteria. The results of these tests indicated that under the conditions of variable deformation during the remelting and pad welding process, the high-temperature brittleness range (HTBR) was equal 246 °C, and it was between 1053 °C and 1299 °C. In this range, the Inconel 713C was prone to hot cracking. The maximum deformation for which the material was resistant to hot cracking was equal to 0.3%. The critical strain speed (CSS) of 1.71 1/s, and the critical strain rate for temperature drop (CST), which in this case was 0.0055 1/°C, should be used as a criteria for assessing the tendency for hot cracking of the Inconel 713C alloy in the HTBR. The developed technological guidelines and hot-cracking criteria can be used to repair Inconel 713C precision castings or modify their surfaces using welding processes.

2014 ◽  
Vol 698 ◽  
pp. 231-236
Author(s):  
Jörg Neumeyer ◽  
Bernard Nacke

In order to weld heavy-walled metal sheets (16mm and more) a hybrid process, that includes an electric arc and the laser beam, is frequently applied at present. Due to the high thermal conductivity of metals and the enormous temperature gradient between the laser-welded area and the not welded region around the bond, there is a great heat flow and the welded material is cooled down in very short time. This high decrease of temperature leads to decayed metallurgical qualities. In order to slow down the temperature drop, an inductive process is applied to the hybrid welding device. Because of the high thickness of the metal sheets both an inductive preheating and an inductive post-heating process are added. To configure an optimal design for the inductors the numerical simulation is used and especially the heat generation of the welding process has to be included in a physical realistic way.


2021 ◽  
Vol 11 (12) ◽  
pp. 5728
Author(s):  
HyeonJeong You ◽  
Minjung Kang ◽  
Sung Yi ◽  
Soongkeun Hyun ◽  
Cheolhee Kim

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.


Author(s):  
Yan Zhang ◽  
DeShui Yu ◽  
JianPing Zhou ◽  
DaQian Sun ◽  
HongMei Li

Abstract To avoid the formation of Ti-Ni intermetallics in a joint, three laser welding processes for Ti alloy–NiTi alloy joints were introduced. Sample A was formed while a laser acted at the Ti alloy–NiTi alloy interface, and the joint fractured along the weld centre line immediately after welding without filler metal. Sample B was formed while the laser acted on a Cu interlayer. The average tensile strength of sample B was 216 MPa. Sample C was formed while the laser acted 1.2 mm on the Ti alloy side. The one-pass welding process involved the creation of a joint with one fusion weld and one diffusion weld separated by the remaining unmelted Ti alloy. The mechanical performance of sample C was determined by the diffusion weld formed at the Ti alloy–NiTi alloy interface with a tensile strength of 256 MPa.


Author(s):  
Pavel Layus ◽  
Paul Kah ◽  
Viktor Gezha

The Arctic region is expected to play an extremely prominent role in the future of the oil and gas industry as growing demand for natural resources leads to greater exploitation of a region that holds about 25% of the world’s oil and gas reserves. It has become clear that ensuring the necessary reliability of Arctic industrial structures is highly dependent on the welding processes used and the materials employed. The main challenge for welding in Arctic conditions is prevention of the formation of brittle fractures in the weld and base material. One mitigating solution to obtain sufficiently low-transition temperatures of the weld is use of a suitable welding process with properly selected parameters. This work provides a comprehensive review with experimental study of modified submerged arc welding processes used for Arctic applications, such as narrow gap welding, multi-wire welding, and welding with metal powder additions. Case studies covered in this article describe welding of Arctic steels such as X70 12.7-mm plate by multi-wire welding technique. Advanced submerged arc welding processes are compared in terms of deposition rate and welding process operational parameters, and the advantages and disadvantages of each process with respect to low-temperature environment applications are listed. This article contributes to the field by presenting a comprehensive state-of-the-art review and case studies of the most common submerged arc welding high deposition modifications. Each modification is reviewed in detail, facilitating understanding and assisting in correct selection of appropriate welding processes and process parameters.


2015 ◽  
Vol 226 ◽  
pp. 95-98
Author(s):  
Robert Kocurek ◽  
Janusz Adamiec

Defining the susceptibility to hot cracking of Inconel 617 alloy welds is essential for assessment welding and pad welding technology. Because of that technological transvarestraint test was performed in the study. Test simulates strains that form in the material during welding. Transvarestraint test enables the assessment of susceptibility to hot cracking and resistance to hot cracking characterized by cracking threshold (εp) and critical strain speed (CSS). Performed investigations enabled to characterize the phenomena occurring in Inconel 617 during welds crystallization, which are important for engineers selecting the joining technology of Inconel 617.


2015 ◽  
Vol 809-810 ◽  
pp. 443-448 ◽  
Author(s):  
Tomasz Kik ◽  
Marek Slovacek ◽  
Jaromir Moravec ◽  
Mojmir Vanek

Simulation software based on a finite element method have significantly changed the possibilities of determining welding strains and stresses at early stages of product design and welding technology development. But the numerical simulation of welding processes is one of the more complicated issues in analyses carried out using the Finite Element Method. A welding process thermal cycle directly affects the thermal and mechanical behaviour of a structure during the process. High temperature and subsequent cooling of welded elements generate undesirable strains and stresses in the structure. Knowledge about the material behaviour subjected to the welding thermal cycle is most important to understand process phenomena and proper steering of the process. The study presented involved the SYSWELD software-based analysis of MIG welded butt joints made of 1.0 mm thickness, 5xxx series aluminium alloy sheets. The analysis of strains and the distribution of stresses were carried out for several different cases of fixing and releasing of welded elements.


2015 ◽  
Vol 1766 ◽  
pp. 29-35 ◽  
Author(s):  
G.Y. Pérez Medina ◽  
M. Padovani ◽  
M. Merlin ◽  
A.F. Miranda Pérez ◽  
F.A. Reyes Valdés

ABSTRACTGas tungsten arc welding-tungsten inert gas (GTAW-TIG) is focused in literature as an alternative choice for joining high strength low alloy steels; this study is performed to compare the differences between gas metal arc welding-metal inert gas (GMAW-MIG) and GTAW welding processes. The aim of this study is to characterize microstructure of dissimilar transformation induced plasticity steels (TRIP) and martensitic welded joints by GMAW and GTAW welding processes. It was found that GMAW process lead to relatively high hardness in the HAZ of TRIP steel, indicating that the resultant microstructure was martensite. In the fusion zone (FZ), a mixture of phases consisting of bainite, ferrite and small areas of martensite were present. Similar phase’s mixtures were found in FZ of GTAW process. The presence of these mixtures of phases did not result in mechanical degradation when the GTAW samples were tested in lap shear tensile testing as the fracture occurred in the heat affected zone. In order to achieve light weight these result are benefits which is applied an autogenous process, where it was shown that without additional weight the out coming welding resulted in a high quality bead with homogeneous mechanical properties and a ductile morphology on the fracture surface. Scanning electron microscopy (SEM) was employed to obtain information about the specimens that provided evidence of ductile morphology.


Author(s):  
Lan Ren ◽  
Kunnayut Eiamsa-ard ◽  
Jianzhong Ruan ◽  
Frank Liou

At present, part remanufacturing technology is gaining more interest from the military and industries due to the benefits of cost reduction as well as time and energy savings. This paper presents the research on one main component of part remanufacturing technology, which is part repairing. Traditionally, part repairing is done in the repair department using welding processes. However, the limitations of the traditional welding process are becoming more and more noticeable when accuracy and reliability are required. Part repairing strategies have been developed utilizing a hybrid manufacturing system in which the laser-aided deposition and CNC cutting processes are integrated. Part repairing software is developed in order to facilitate the users. The system and the software elevate the repairing process to the next level, in which accuracy, reliability, and efficiency can be achieved. The concept of the repairing process is presented in this paper, and verification and experimental results are also discussed.


Author(s):  
Elisan dos Santos Magalhaes ◽  
Cristiano Pedro da Silva ◽  
Ana Lúcia Fernandes Lima e Silva ◽  
Sandro Metrevelle Marcondes Lima e Silva

Purpose The purpose of this article is the determination of the temperature fields in a weld region has always been an obstacle to the improvement of welding processes. As an alternative, the use of inverse problems to determine the heat flux during the welding process allows an analysis of these processes. Design/methodology/approach This paper studies an alternative for the thermal analysis of the tungsten inert gas welding process on a 6,060 T5 aluminum alloy. For this purpose, a C++ code was developed, based on a transient three-dimensional heat transfer model. To estimate the amount of heat delivered to the plate, the specification function technique was used. Lab experiments were carried out to validate the methodology. A different experimental methodology is proposed to estimate the emissivity (radiation coefficient). Findings The maximum difference between experimental and numerical temperatures is lower than 5 per cent. The determined emissivity value for the aluminum 6,060 T5 presented a good agreement with literature values. The thermal fields were analyzed as function of the positive polarity. The specification function method proved to be an adequate tool for heat input estimation in welding analysis. Originality/value The proposed methodology proves to be a cheaper way to estimate the heat flux on the sample. The estimated power curves for the welding process are presented. The methodology to calculate the emissivity (radiation coefficient) was validated.


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