Brazing Technology

 

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

 

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

 

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

 

Fe-amorph - Simulation-aided material design of iron-based amorphous brazing foils

Short description:

In order to meet the increasing requirements of different areas in mechanical engineering, new alloying concepts for brazing have to satisfy constantly growing requirements in terms of mechanical properties and corrosion resistance. The use of amorphous brazing foils for the brazing of steel offers several advantages over conventional alloys. On the one hand, the foils, produced by Melt Spinning, are flexible and can be better adapted to the component geometry that has to be brazed, and on the other hand, the environmental impact is lower, since no organic binders are required compared to brazing pastes and powders. Ni-based alloys are frequently used for amorphous brazing foils. Due to the high raw material prices for nickel, an Fe-based brazing material is preferable. For the alloy development, it is important to aim for amorphous solidification of the brazing foils, as this counteracts embrittlement. The GFA (glass forming ability) is an important empirical parameter representing the tendency of a metallic melt to solidify amorphously.The experimental determination of the GFA and the alloy optimization based on it, is extremely costly and time-consuming. The reason for this is that the investigated alloys are multicomponent systems. A simulation-based material design using the CALPHAD method (calculation of phase diagrams) should help to indentify promising alloy compositions with respect to the GFA tendency. Subsequently, the results of the simulation will be validated experimentally. The alloy design can thus be supported by numerical calculations in the future.

Funding:	Deutsche Forschungsgemeinschaft (DFG)
Porject number:	B0 1979/80-1
Duration:	Probably: 01.08.2021-31.07.2023