Brazing Technology

Contact

Name

Julian Hebing

Team Leader Brazing Technology

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work
+49 241 80 99960

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Network for the development and qualification of efficiency-maintaining protective coatings against erosion and corrosion of turbine blades in steam/gas turbines and compressors - Coat4Turbine.NRW

Short description:

The aim of the research project is the development of erosion and corrosion protective coatings, which results in preservation of the efficiency-optimized contours and the increase of the service life of rotating steam turbine and compressor blades. Innovative coating concepts are developed, manufactured, tested and applied on industry-oriented components. In the field of brazing technology, the sub-goal is to evaluate Ni- and Fe-based coatings with different contents of chromium or tungsten carbides for steam turbine blades made of X12CrNiMo12 steel as protection against water droplet erosion and corrosion. The use of these protective coatings results in permanently high efficiency, increased life cycle efficiency and, above all, enormous CO2 savings. Poster EFRE-0801003

Funding: European Regional Development Fund (ERDF)
Porject number: EFRE-0801003
Duration: March 23, 2018 to March 22, 2021

 
 

Development of innovative tapes, presintered preforms and process parameters for repair brazing of gas turbine components

Short description:

The aim of the research project is to develop pore-free and low-shrinkage green tapes and presintered preforms made of Ni- and Co-based materials. Additionally, an adapted process for repair brazing of turbine components is designed. This process should cover the application method for the tapes and preforms as well as novel approaches for the brazing process parameters. Starting point is the analysis of the influence of the grain size distribution of braze metal and additive powders used to produce the tapes and preforms. Poster EFRE-0801003

Funding: European Regional Development Fund (ERDF)
Porject number: EFRE-0801003
Duration: March 23, 2018 to March 22, 2021

 
 

Optimization of carbide-steel brazed joints regarding strength, performance and reliability by improving process control in induction brazing

Short description:

The aim of the research project is to improve the temperature control during induction brazing and thus to increase the reproducibility and quality of the brazed joints. As a result of the liquefaction of the filler metal and the sinking of the upper substrate, geometry and force changes occur in the brazing process on the component. By using high-resolution force and displacement sensors, the sinking of the substrate during melting of the filler metal can be detected. As a result of the improved sensor technology, it is possible to develop a controller which takes account of the filler metal state in addition to the conventional surface temperature. Thus, it is possible to neglect many disturbance variables, such as the influence of the component geometry, the heating rate or the heat conduction and to produce high quality brazed components with reproducible strength. Poster 19.201 N

Funding: Arbeitsgemeinschaft industrieller Forschungsvereinigungen „Otto von Guericke“ (AiF)
Porject number: 19.201 N
Duration: 01.01.2017 bis 30.06.2019

 
 

Influence of solid-liquid reactions in the brazing gap on joint properties and precision

Short description:

The aim of the project is to reduce the quantity of intermetallic compounds in the brazing seam and the effect of the heat treatment on the base material when joining hot work tool steels with a nickel based filler metal. Thus to improve the mechanical and thermal properties of the joint will be improved. In order to achieve this the grain growth will be reduced by an adapted temperature control and by electric current assisted brazing which results in accelerated and directed diffusion during brazing. Poster SFB 1120 – Teilprojekt A5

Funding: German Research Foundation (DFG)
Porject number: SFB 1120 – Project A5
Duration: July 1, 2018 to June 30, 2022

 
 

Surface pretreatment of steel sheets for die casting of gap-free and low-distortion cast aluminum/steel sheet metal hybrids

Short description:
The aim of the research project is to produce gap-free and low-distortion hybrid Al/steel-components by high pressure die casting. For this purpose, coatings are applied on steel insert by means of thermal spraying and deposition brazing, which enable a metallurgical bonding or solid form closure connection to the steel sheet and Al-cast during the casting process. The second phase of the project focuses on the „WING“ high pressure die casing tool as a geometrically more complex hybrid tool. This allows the scientific investigation of relevant parameters and mechanisms of the individual process steps and their interactions at the required level of complexity. Therefore, the overall goal of the planned project is on the one hand the exp. Development of the relevant mechanisms and their dependencies on process and material parameters along the production chain. With the help of developed criterion functions in combination with thermophysical simulations, areas of the substrate that are suitable for structuring and/or those areas in which a coating is more likely to enable the optimum bond between aluminium casting and steel are to be determined.

Funding: German Research Foundation (DFG)
Porject number: BO 1979/39-2
Duration: July 1, 2020 to June 30, 2022
 
 

Influence of solid-liquid reactions in the brazing gap on joint properties and precision

Short description:

The aim of the subproject A5 is to reduce the quantity of intermetallic compounds in the brazing seam and the effect of the heat treatment on the base material when joining hot work tool steels with a nickel-based filler metal. Thus, the mechanical and thermal properties of the joint will be improved. In order to achieve this, the grain growth will be reduced by an adapted temperature control and by electric current assisted brazing which results in accelerated and directed diffusion during brazing. Poster SFB 1120 – Teilprojekt A5

Funding: German Research Foundation (DFG)
Porject number: SFB 1120 – Project A5
Duration: July 1, 2018 to June 30, 2022

 
 

2BeSafe2 - Development of design concepts for the assessment of the fatigue strength of brazed joints under consideration of process-related brazing seam conditions

Short description:

As a result of efforts to further increase engine performance and environmental policy objectives, the demands on dynamically stressed components in the automotive sector are constantly increasing. In order to use the fuel more and more efficiently, engines with gasoline direct injection operate with ever higher injection pressures in the common rail systems of p > 350 bar with simultaneous reduction of wall thicknesses. An economical design of these highly dynamically loaded brazed joints is of great importance. The few currently available approaches for evaluating the fatigue strength of brazed joints do not take into account the real, microscopic condition of the brazed seam, but refer to idealized fillets. In addition, various damage mechanisms occur that have not been considered in the design concepts so far. This results in a relatively large dispersion, which makes it necessary to design components much more conservatively than necessary.This problem, which is particularly relevant in the automotive industry, is to be solved in this project by deriving reliable design concepts for brazed joints with realistic brazing seam conditions. Different influencing variables such as type and duration of the brazing process, but also geometrical deviations of the component geometries are recorded and used to derive holistic design concepts.

Funding: Arbeitsgemeinschaft industrieller Forschungsvereinigungen „Otto von Guericke“ (AiF)
Porject number: 20.370 N
Duration: January 1, 2019 to June 30, 2022
 
 

Adamant - Immunize of Ni and Fe based filler metals to improve bonding properties

Short description:

The manufacture of high-strength joints using a wide variety of brazing technologies is state of the art in a wide range of industrial sectors. The classes of Ni- and Fe-based filler metal alloys have proved particularly suitable for applications at high temperatures and simultaneous corrosive stress, such as in the exhaust tract of motor vehicles or for the repair of turbine blades. The alloying concepts of the Ni and Fe filler metals most commonly used in industry are very similar and are based on the respective main alloying element, i.e. Ni or Fe, Cr to improve corrosion resistance and mechanical properties, and elements which lower the melting point. Typically, the metalloids silicon, boron and phosphorus are used for this purpose. However, these elements favour the formation of hard and brittle phosphides, borides and silicides. The brittle phases are not only metallurgical notches, the phase bands formed from them also fail brittle due to their low toughness, so that spontaneous component failure occurs in case of overload. Previous concepts for avoiding these brittle phases are associated with very high technical effort and economic costs. One possibility, which has not been considered so far, is the improvement of the mechanical properties by interrupting the hard phase bands by means of targeted precipitation formation. The addition of even small amounts of Ti can significantly improve the strength of these brazed joints. The aim of the project is to investigate this approach and make it usable for industrial application.

Funding: Arbeitsgemeinschaft industrieller Forschungsvereinigungen „Otto von Guericke“ (AiF)
Porject number: 21.231 N
Duration: June 1, 2020 to November 30, 2022