scholarly journals MAG Welding Process with Micro-Jet Cooling as the Effective Method for Manufacturing Joints for S700MC Steel

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 276
Author(s):  
Tomasz Węgrzyn ◽  
Tadeusz Szymczak ◽  
Bożena Szczucka-Lasota ◽  
Bogusław Łazarz

Advanced high-strength steel (AHSS) steels are relatively not very well weldable because of the dominant martensitic structure with coarse ferrite and bainite. The utmost difficulty in welding these steels is their tendency to crack both in the heat affected zone (HAZ) and in weld. The significant disadvantage is that the strength of the welded joint is much lower in comparison to base material. Adopting the new technology regarding micro-jet cooling (MJC) after welding with micro-jet cooling could be the way to steer the microstructure of weld metal deposit. Welding with micro-jet cooling might be treated as a very promising welding S700MC steel process. Tensile and fatigue tests were mainly carried out as the main destructive experiments for examining the weld. Also bending probes, metallographic structure analysis, and some non-destructive measurements were performed. The welds were created using innovative technology by MAG welding with micro-jet cooling. The paper aims to verify the fatigue and tensile properties of the thin-walled S700MC steel structure after welding with various parameters of micro-cooling. For the first time, micro-jet cooling was used to weld S700MC steel in order to check the proper mechanical properties of the joint. The main results are processed in the form of the Wöhler’s S–N curves (alternating stress versus number cycles to failure).

2014 ◽  
Vol 891-892 ◽  
pp. 1488-1493 ◽  
Author(s):  
José Azevedo ◽  
Virgínia Infante ◽  
Luisa Quintino ◽  
Jorge dos Santos

The development and application of friction stir welding (FSW) technology in steel structures in the shipbuilding industry provide an effective tool of achieving superior joint integrity especially where reliability and damage tolerance are of major concerns. Since the shipbuilding components are inevitably subjected to dynamic or cyclic stresses in services, the fatigue properties of the friction stir welded joints must be properly evaluated to ensure the safety and longevity. This research intends to fulfill a clear knowledge gap that exists nowadays and, as such, it is dedicated to the study of welded steel shipbuilding joints in GL-A36 steel, with 4 mm thick. The fatigue resistance of base material and four plates in as-welded condition (using several different parameters, tools and pre-welding conditions) were investigated. The joints culminate globally with defect-free welds, from which tensile, microhardness, and fatigue analyses were performed. The fatigue tests were carried out with a constant amplitude loading, a stress ratio of R=0.1 and frequency between 100 and 120 Hz. The experimental results show the quality of the welding process applied to steel GL-A36 which is reflected in the mechanical properties of joints tested.


2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Ho Thi My Nu ◽  
Truyen The Le ◽  
Luu Phuong Minh ◽  
Nguyen Huu Loc

The selection of high-strength titanium alloys has an important role in increasing the performance of aerospace structures. Fabricated structures have a specific role in reducing the cost of these structures. However, conventional fusion welding of high-strength titanium alloys is generally conducive to poor mechanical properties. Friction welding is a potential method for intensifying the mechanical properties of suitable geometry components. In this paper, the rotary friction welding (RFW) method is used to study the feasibility of producing similar metal joints of high-strength titanium alloys. To predict the upset and temperature and identify the safe and suitable range of parameters, a thermomechanical model was developed. The upset predicted by the finite element simulations was compared with the upset obtained by the experimental results. The numerical results are consistent with the experimental results. Particularly, high upset rates due to generated power density and forging pressure overload that occurred during the welding process were investigated. The performances of the welded joints are evaluated by conducting microstructure studies and Vickers hardness at the joints. The titanium rotary friction welds achieve a higher tensile strength than the base material.


2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Kai Treutler ◽  
Volker Wesling

AbstractWelding-related loss of strength, especially in the case of fatigue, significantly reduces the range of applications for high-strength fine-grained structural steels. In order to counteract this situation, the aim of the work is to increase the strength of welded joints made of high-strength fine-grained structural steels by using coated welding consumables. This is described using the example of a titanium coating for quasi-static and abrupt dynamic load and fatigue. The thermomechanical rolled fine-grained structural steel S700MC is used as the base material, using a welding filler of the same type. MAG welding was used to produce the fillet welds on a T-joint. In addition to tensile tests at four different load speeds up to 2 m/s, the results of fatigue tests are presented. In addition, the microstructure of the weld seams is examined by metallographic methods and the scanning electron microscope. A comparison with two joints from an unmodified variant and another steel grade with comparable properties (S690QL) serves to classify the results. It is shown that the use of modified filler metals has a significant influence on the overall strength of the welded joint due to the rounding of the weld toe. Thus, the fatigue strength can be increased by around 50%. In addition, the strength under sudden dynamic load can be increased by 10%.


2006 ◽  
Vol 519-521 ◽  
pp. 1809-1814 ◽  
Author(s):  
Robert B. Wagstaff ◽  
David J. Lloyd ◽  
Todd F. Bischoff

Novelis Inc. recently released its first new innovative technology which opens new opportunities in the clad aluminum product marketplace, where a combination of mechanical and physical properties can be obtained which are superior to the monolithic material alone. Clad aerospace and brazing products are well known commercial products which are provided by commercial roll bonding processes, but which can now be produced with the new Novelis technology. This paper discusses the new technology, e.g., the casting, fabrication, the properties of clad sheet are reported and it is established that the clad-core interface is comprised of a high strength, oxide free zone. This technology enables a new family of clad products with clad/core combinations which cannot be produced by the conventional roll bonding process.


2021 ◽  
Vol 100 (12) ◽  
pp. 396-409
Author(s):  
ABDELBASET R. H. MIDAWI ◽  
◽  
ELLIOT BIRO ◽  
SRINATH KISTAMPALLY

Advanced high-strength steels (AHSS) such as complexphase (CP) and high-formability (HF) steel offer weightsaving advantages for automotive applications such as chassis and frame applications. To prevent material oxidation, materials are often galvanized to protect the substrate from corrosion. However, the weldability of coated AHSS becomes challenging due to the trapping of zinc in the weld molten pool, which could lead to weld defects such as porosity and liquid metal embrittlement cracks. This work focused on the weldability of AHSS (CP800 and 980HF) using the gas metal arc welding process. The roles of both galvanized iron coating and filler material on weld strength were investigated. The welds were performed using two different filler materials: a low-strength filler (ER70S-6) and a high-strength filler (ER100S-6) material. In addition, two different joint configurations were studied: lap joints and butt joints. The results showed that the butt joint had a higher strength compared to the lap joints. Furthermore, the strength of the butt joint overmatched the base material strength in all of the tested materials (both in galvanized and uncoated). In general, lap joint strength undermatched the base material strength, which was attributed to the rotation during tensile testing that induced unaccounted bending stress on the lap joint, while using a higherstrength welding wire improved the tensile strength material in the lap joint configuration. The hardness profiles in the 980HF steel also showed a significant hardness mismatch due to the formation of a fully martensitic microstructure in the heat-affected zone, which led to suppressing the deformation across the lap joint.


Author(s):  
Alan Glover ◽  
Joe Zhou ◽  
David Horsley ◽  
Nobuhisa Suzuki ◽  
Shigeru Endo ◽  
...  

Traditional pipeline technology will be severely challenged as design-operating pressures continue to rise and gas field developments occur in more remote locations including the arctic. Cost-effective solutions to these issues can be found through innovative designs using new technology and its implementation. Some of these designs have considered the use of high-pressure natural gas pipelines resulting in the development of high strength steel. In order to meet these increases in pressure TransCanada and JFE/NKK have been working extensively on the application of X100 (Grade 690) linepipe and this has culminated in the construction and installation of a X100 project in the fall of 2002. This paper will discuss the development of the related research projects that allowed the successful completion of the field project. The topics will include the material properties and fracture control plans for X100. In addition the approach to strain based design for X100 will include the analysis for both the tensile strain limits (weld mismatch consideration) and compressive strain limits (i.e. buckling capacity). The development of the field welding process will also be covered. The paper will discuss the implications of using X100 from the perspective of the successful field project and the application of a strain-based design.


2020 ◽  
Vol 59 (1) ◽  
pp. 54-66
Author(s):  
Francois Njock Bayock ◽  
Paul Kah ◽  
Antti Salminen ◽  
Mvola Belinga ◽  
Xiaochen Yang

AbstractThis study concerns the weldability of dissimilar Ultra high-strength steel (UHSS) and advanced high-strength steel (AHSS), which is used in the modern machine industry. The materials offered superior strength as well as relatively low weight, which reduces microstructure contamination during a live cycle. The choice of the welding process base of the base material (BM) and welding parameters is essential to improve the weld joint quality. S700MC/S960QC was welded using a gas metal arc welding (GMAW) process and overmatched filler wire, which was performed using three heat input (7, 10, and 15 kJ/cm). The weld samples were characterized by a Vickers-hardness test, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The test reveals a decrease of softening areas in the HAZ and the formation of the stable formation of Bainite-Ferrite for S700MC and Bainite-martensite for S960QC when the heat input of 10 kJ/cm is used. It is recommended to use the GMAW process and Laser welding (Laser beam-MIG), with an optimal welding parameter, which will be achieved a high quality of manufacturing products.


Author(s):  
Benjamin Kessler ◽  
Dirk Dittrich ◽  
Berndt Brenner ◽  
Jens Standfuss ◽  
Christoph Leyens

AbstractThe joining of thick-walled components using beam-based joining techniques is content of worldwide research and development activities, but has not yet been established in industry. State of the art to weld nickel super alloys is currently a TIG narrow-gap welding. The present paper is focusing on a new specific laser beam welding process, the so-called Laser Multi-Pass Narrow-Gap welding (Laser-MPNG). It first explains the process principle based on 2D beam oscillation, the use of fiber lasers and the multi-pass principle. The potential of the Laser-MPNG welding process is demonstrated using the technically significant nickel-based material Alloy 617 occ. As a result, it was possible for the first time to realize a weld with a wall thickness of 140 mm free of cracks or bonding defects. Promising results of creep and low-cycle fatigue tests are used to show the potential that Laser-MPNG welded joints would have for future industrial applications.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5411
Author(s):  
Konstantin Prabitz ◽  
Marlies Pichler ◽  
Thomas Antretter ◽  
Holger Schubert ◽  
Benjamin Hilpert ◽  
...  

Resistance spot welding (RSW) is a common joining technique in the production of car bodies in white for example, because of its high degree of automation, its short process time, and its reliability. While different steel grades and even dissimilar metals can be joined with this method, the current paper focuses on similar joints of galvanized advanced high strength steel (AHSS), namely dual phase steel with a yield strength of 1200 MPa and high ductility (DP1200HD). This material offers potential for light-weight design. The current work presents a multi-physical finite element (FE) model of the RSW process which gives insights into the local loading and material state, and which forms the basis for future investigations of the local risk of liquid metal assisted cracking and the effect of different process parameters on this risk. The model covers the evolution of the electrical, thermal, mechanical, and metallurgical fields during the complete spot welding process. Phase transformations like base material to austenite and further to steel melt during heating and all relevant transformations while cooling are considered. The model was fully parametrized based on lab scale material testing, accompanying model-based parameter determination, and literature data, and was validated against a large variety of optically inspected burst opened spot welds and micrographs of the welds.


2013 ◽  
Vol 58 (4) ◽  
pp. 1067-1070 ◽  
Author(s):  
T. Wegrzyn ◽  
J. Piwnik ◽  
D. Hadrys

Abstract Until that moment micro-jet technology was tested only for MIG welding process with argon as a shielded gas. An article presents actual information about innovate welding technology with micro-jet cooling. There are put down information about gases that could be chosen both for MIG/MAG welding and for micro-jet process. There were given information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was presented in terms of oxygen amount in WMD (weld metal deposit).


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