FG Fügetechnik

18 Items

Recent Submissions
Lamé curve approximation for the assessment of the 3D temperature distribution in keyhole mode welding processes

Artinov, Antoni ; Karkhin, Victor ; Bakir, Nasim ; Meng, Xiangmeng ; Bachmann, Marcel ; Gumenyuk, Andrey ; Rethmeier, Michael (2020-05-04)

A novel approach for the reconstruction of an equivalent volumetric heat source from a known weld pool shape is proposed. It is based on previously obtained weld pool geometries from a steady-state thermo-fluid dynamics simulation. Hereby, the weld pool dimensions are obtained under consideration of the most crucial physical phenomena, such as phase transformations, thermo-capillary convection,...

Theoretical study of influence of electromagnetic stirring on transport phenomena in wire feed laser beam welding

Meng, Xiangmeng ; Artinov, Antoni ; Bachmann, Marcel ; Rethmeier, Michael (2020-04-29)

The additional element from the filler wire in the laser beam welding is usually distributed inhomogeneously in the final weld due to the high solidification rate of weld pool. It has been found that the electromagnetic stirring produced by an external oscillating magnetic field can enhance the material mixing in the weld pool to achieve a more uniform element distribution. However, the magneti...

Mathematical modeling of the geometrical differences between the weld end crater and the steady-state weld pool

Artinov, Antoni ; Karkhin, Victor ; Bachmann, Marcel ; Rethmeier, Michael (2020-04-28)

The geometrical characteristics of the weld end crater are commonly used as a means of validating numerical results in welding simulations. In this paper, an analytical model is developed for calculating the cooling stage of the welding process after the moving energy source is turned off. Solutions for various combinations of heat sources and heated bodies are found. It is shown that after tur...

Influence of welding parameters on electromagnetic supported degassing of die-casted and wrought aluminum

Fritzsche, André ; Hilgenberg, Kai ; Rethmeier, Michael (2020-04-29)

Laser beam welding of aluminum die casting is challenging. A large quantity of gases (in particular, hydrogen) is absorbed by aluminum during the die-cast manufacturing process and is contained in the base material in solved or bound form. After remelting by the laser, the gases are released and are present in the melt as pores. Many of these metallurgic pores remain in the weld seam as a resul...

Full penetration laser beam welding of thick duplex steel plates with electromagnetic weld pool support

Avilov, Vjaceslav ; Fritzsche, André ; Bachmann, Marcel ; Gumenyuk, Andrey ; Rethmeier, Michael (2016-03-31)

Full penetration high power bead-on-plate laser beam welding tests of up to 20 mm thick 2205 duplex steel plates were performed in PA position. A contactless inductive electromagnetic (EM) weld pool support system was used to prevent gravity drop-out of the melt. Welding experiments with 15 mm thick plates were carried out using IPG fiber laser YLR 20000 and Yb:YAG thin disk laser TruDisk 16002...

Finite element modeling of an alternating current electromagnetic weld pool support in full penetration laser beam welding of thick duplex stainless steel plates

Bachmann, Marcel ; Kunze, Richard ; Avilov, Vjaceslav ; Rethmeier, Michael (2016-03-31)

An electromagnetic weld pool support system for 20 mm thick duplex stainless steel AISI 2205 was investigated numerically and compared to experiments. In our former publications, it was shown how an alternating current (AC) magnetic field below the process zone directed perpendicular to the welding direction can induce vertically directed Lorentz forces. These can counteract the gravitational f...

Increasing Performance and Energy Efficiency of Gas Metal Arc Welding by a High Power Tandem Process

Sproesser, Gunther ; Pittner, Andreas ; Rethmeier, Michael (2016-02-19)

Standard Gas Metal Arc Welding (Standard GMAW) and a high power Tandem GMAW (TGMAW) process are evaluated with respect to energy efficiency. Current, voltage and overall equipment power are measured and energy consumption is determined. The new key performance indicator Electrical Deposition Efficiency is introduced to reflect the energy efficiency of GMAW processes. Additionally, wall-plug eff...

Sustainable Welding Process Selection Based on Weight Space Partitions

Sproesser, Gunther ; Schenker, Sebastian ; Pittner, Andreas ; Borndörfer, Ralf ; Rethmeier, Michael ; Chang, Ya-Ju ; Finkbeiner, Matthias (2016-02-19)

Selecting a welding process for a given application is crucial with respect to the sustainability of part manufacturing. Unfortunately, since welding processes are evaluated by a number of criteria, preferences for one or the other process can be contradictory. However, the prevalent procedure of weight assignment for each criterion is subjective and does not provide information about the entir...

Laser Metal Deposition as Repair Technology for a Gas Turbine Burner Made of Inconel 718

Petrat, Torsten ; Graf, Benjamin ; Gumenyuk, Andrey ; Rethmeier, Michael (2016-09-19)

Maintenance, repair and overhaul of components are of increasing interest for parts of high complexity and expensive manufacturing costs. In this paper a production process for laser metal deposition is presented, and used to repair a gas turbine burner of Inconel 718. Different parameters for defined track geometries were determined to attain a near net shape deposition with consistent build-u...

Experimental and numerical study on the influence of the laser hybrid parameters in partial penetration welding on the solidification cracking in the weld root

Bakir, Nasim ; Üstündağ, Ömer ; Gumenyuk, Andrey ; Rethmeier, Michael (2020-01-27)

The aim of the present study is to investigate the influence of the laser hybrid welding parameters on the solidification cracks in the weld root for partial penetration welding. Welding trials were performed on thick-walled high-strength steels of grade S690QL under the same critical restraint intensity, with a variation of the welding velocity, wire feeding rate, and the focal position of the...

Automated Tool‐Path Generation for Rapid Manufacturing of Additive Manufacturing Directed Energy Deposition Geometries

Biegler, Max ; Wang, Jiahan ; Kaiser, Lukas ; Rethmeier, Michael (2020-05-08)

In additive manufacturing (AM) directed energy deposition (DED), parts are built by welding layers of powder or wire feedstock onto a substrate with applications for steel powders in the fields of forging tools, spare parts, and structural components for various industries. For large and bulky parts, the choice of tool‐paths influences the build rate, the mechanical performance, and the distort...

Build-up strategies for additive manufacturing of three dimensional Ti-6Al-4V-parts produced by laser metal deposition

Spranger, Felix ; Graf, Benjamin ; Schuch, Michael ; Hilgenberg, Kai ; Rethmeier, Michael (2018-03-23)

Laser metal deposition (LMD) has been applied as a coating technology for many years. Today, the technologies capacity to produce 3D depositions leads to a new field of application as additive manufacturing method. In this paper, 3D laser metal deposition of titanium alloy Ti-6Al-4 V is studied with special regard to the demands of additive manufacturing. Therefore, only the coaxial LMD powder ...

On the search for the origin of the bulge effect in high power laser beam welding

Artinov, Antoni ; Bakir, Nasim ; Bachmann, Marcel ; Gumenyuk, Andrey ; Na, Suck-Joo ; Rethmeier, Michael (2019-04-17)

The shape of the weld pool in laser beam welding plays a major role in understanding the dynamics of the melt and its solidification behavior. The aim of the present work was its experimental and numerical investigation. To visualize the geometry of the melt pool in the longitudinal section, a butt joint configuration of 15 mm thick structural steel and transparent quartz glass was used. The we...

Quantifying Mechanical Properties of Automotive Steels with Deep Learning Based Computer Vision Algorithms

Javaheri, Ehsan ; Kumala, Verdiana ; Javaheri, Alireza ; Rawassizadeh, Reza ; Lubritz, Janot ; Graf, Benjamin ; Rethmeier, Michael (2020-01-22)

This paper demonstrates that the instrumented indentation test (IIT), together with a trained artificial neural network (ANN), has the capability to characterize the mechanical properties of the local parts of a welded steel structure such as a weld nugget or heat affected zone. Aside from force-indentation depth curves generated from the IIT, the profile of the indented surface deformed after ...

Mechanical Properties Characterization of Welded Automotive Steels

Javaheri, Ehsan ; Lubritz, Janot ; Graf, Benjamin ; Rethmeier, Michael (2019-12-18)

Among the various welding technologies, resistance spot welding (RSW) and laser beam welding (LBW) play a significant role as joining methods for the automobile industry. The application of RSW and LBW for the automotive body alters the microstructure in the welded areas. It is necessary to identify the mechanical properties of the welded material to be able to make a reliable statement about t...

Laser Welding of SLM-Manufactured Tubes Made of IN625 and IN718

Jokisch, Torsten ; Marko, Angelina ; Gook, Sergej ; Üstündag, Ömer ; Gumenyuk, Andrey ; Rethmeier, Michael (2019-09-12)

The advantage of selective laser melting (SLM) is its high accuracy and geometrical flexibility. Because the maximum size of the components is limited by the process chamber, possibilities must be found to combine several parts manufactured by SLM. An application where this is necessary, is, for example, the components of gas turbines, such as burners or oil return pipes, and inserts, which can...

Numerical Simulation on the Origin of Solidification Cracking in Laser Welded Thick-Walled Structures

Bakir, Nasim ; Artinov, Antoni ; Gumenyuk, Andrey ; Bachmann, Marcel ; Rethmeier, Michael (2018-06-01)

One of the main factors affecting the use of lasers in the industry for welding thick structures is the process accompanying solidification cracks. These cracks mostly occurring along the welding direction in the welding center, and strongly affect the safety of the welded components. In the present study, to obtain a better understanding of the relation between the weld pool geometry, the stre...

Improvement of Filler Wire Dilution Using External Oscillating Magnetic Field at Full Penetration Hybrid Laser-Arc Welding of Thick Materials

Üstündağ, Ömer ; Avilov, Vjaceslav ; Gumenyuk, Andrey ; Rethmeier, Michael (2019-05-23)

Hybrid laser-arc welding offers many advantages, such as deep penetration, good gap bridge-ability, and low distortion due to reduced heat input. The filler wire which is supplied to the process is used to influence the microstructure and mechanical properties of the weld seam. A typical problem in deep penetration high-power laser beam welding with filler wire and hybrid laser-arc welding is a...