Future regeneration processes for high-pressure turbine blades

Nicolaus, Martin; Rottwinkel, Boris; Alfred, Irene; Möhwald, Kai; Nölke, Christian; Kaierle, Stefan; Maier, Hans Jürgen; Wesling, Volker

doi:10.1007/s13272-017-0277-9

Cited by 9 publications

(5 citation statements)

References 9 publications

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“…They found an isothermal solidified gap of approximately 1000 µm with a six-hour treatment. Nicolaus et al [3][4][5] developed a hybrid process for repairing high-pressure turbine blades.…”

Section: Base Alloy Alloys Filler Metal Thickness Brazing Microstrucmentioning

confidence: 99%

“…Because of its versatility, BNi-9 (MBF 80, Nicobraz 150) has been extensively studied in base Ni alloys, base Co alloys and stainless steel. This filler material can be applied as either a foil or paste, each one having a specific application; an amorphous foil provides more uniform joints assemblies [1], and powders mixed with a binder and paste are used to repair cracks and wear defects [2][3][4][5][6][7]. In Table 1, the experimental conditions of some of these studies have been summarized.…”

Section: Introductionmentioning

confidence: 99%

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Metallurgical Interaction among BNi-9 and Waspaloy, FSX-414 or 304-Type Stainless Steel under TLP Cycle

Flores-Escareño

Castro‐Román

Hernández-García³

et al. 2020

Metals

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The metallurgical interaction of BNi-9 filler metal paste with Waspaloy, Ni-coated Waspaloy, FSX-414, and 304-SS is studied in a brazing treatment under an argon atmosphere with an isothermal hold for one hour at 1150 °C. The Waspaloy alloys were brazed under both solubilized and aging conditions. Before brazing, some Waspaloy samples were electrochemically coated with an Ni layer 35-40 μm thick. The microstructures of the FSX-414 and 304-SS alloys showed that the thickness of the isothermal solidification zones was approximately 50 μm, while this thickness was not well defined in the Waspaloy samples. The Ni-coated solubilized Waspaloy showed a wider diffusive zone, which was associated with an increase in the penetration extension of the liquid films. The analysis of grain orientation in all brazed zones of the Waspaloy samples showed aleatory characteristics. Plastic factors in the different brazed zones were also obtained by nanoindentation under 350 mN loads. It was observed that the plastic factor was low when the width of the diffusive zone increased. The plastic factor in the Ni-coated Waspaloy was the lowest, while the diffusive zone in this sample had the largest width. The BNi-9 wettability is better in FSX-414, and 304-SS than in Waspaloy. Ni coating in Waspaloy improves BNi-9 wettability.

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Section: Base Alloy Alloys Filler Metal Thickness Brazing Microstrucmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Metallurgical Interaction among BNi-9 and Waspaloy, FSX-414 or 304-Type Stainless Steel under TLP Cycle

Flores-Escareño

Castro‐Román

Hernández-García³

et al. 2020

Metals

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“…Brazing foil that is flexible and has an organic binder amorphous foils, etc. The elements makeup of a braze alloy is influenced by the type of braze alloy used, which is determined by the specific engineering purpose [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Martensitic Stainless Steel Brazing by Using Ag-Cu-Ti as Active Filler Metal Alloys

Muhammed¹,

Hashim²,

Ayad³

2023

ETJ

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 M artensitic stainless steel was welded by the brazing method  The mechanical properties were evaluated by the single-shear experiment.  Optical microscopy was used to study the microstructure of the weld joint.Brazing fillers for joining applications are essential to advanced material design and fabrication. Several types of brazing fillers have been developed in recent decades to join similar or different engineering materials. Important parts of automotive and aircraft components, including steel, are often joined by brazing.In this study, Similar samples of martensitic stainless steel were welded by the brazing method, using effective silver-based metal alloys. The brazing welding is done in inert gas atmosphere furnaces, by placing the samples in a special container filled with argon gas during the welding period and at a flow rate (10 to 15 minutes) inside a cylindrical furnace. Three types of metal alloys (silver, copper, and titanium) with different weight ratios of Ag, Cu, and Ti were used with a fixed welding time (10 minutes) at an appropriate temperature for each joint. A set of examinations and tests were conducted to find out the microscopic structure of the bonding site and the extent of the binder overlapping with the base material.Optical microscopy was used to study the microstructure of the weld joint. Optical and scanning electron microscopy (SEM ) is used to study the joint microstructure. All joints of samples exhibited continuous bonding between the base metal and the filler metal, good wetting between the surfaces, and it was also noticed that the higher the proportion of titanium, the better the wetting between the surfaces., the greater the percentage of diffusion of the filler elements and the strength of the bonding with the base metal. The use of titanium-containing fillers in brazing is good for bonding in turbine blades of martensitic steel.

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“…This repair process is expensive and consists of several process steps. In earlier works, it is shown that the repair process for turbine blades can be shortened by using a two-stage hybrid joining and coating technology [14,15]. The idea of this hybrid technology is as follows:…”

Section: Introductionmentioning

confidence: 99%

Thermally Sprayed Nickel-Based Repair Coatings for High-Pressure Turbine Blades: Controlling Void Formation during a Combined Brazing and Aluminizing Process

2021

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Turbine blades must withstand severe loading conditions and damage can occur during operation due to heat, pressure, foreign objects and hot gas corrosion, despite the protective coatings applied onto the turbine blades. Instead of replacing the damaged components, maintenance, repair and overhaul are key to extend the total service life. Besides welding, the repair of turbine blades by brazing is an established repair process in the industry and involves many individual steps that often require a high degree of manual work. In the present study, a hybrid joining and coating technology was developed to shorten the state-of-the-art process chain for repairing turbine blades. With this approach, a repair coating, which consists of a filler metal, a hot gas corrosion protective layer and an aluminum top layer, is applied by atmospheric plasma spraying. The coated turbine blade then undergoes a heat-treatment so that a brazing and aluminizing process is carried out simultaneously. Due to diffusion and segregation processes, pores can occur in the heat-treated coating. In the present study, a full factorial design of experiment was performed to reduce the pores in the coating. The microstructure of the repair coating was investigated by optical- and scanning electron microscopy (SEM), and the impact of the process parameters on the resulting microstructure is discussed.

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Future regeneration processes for high-pressure turbine blades

Cited by 9 publications

References 9 publications

Metallurgical Interaction among BNi-9 and Waspaloy, FSX-414 or 304-Type Stainless Steel under TLP Cycle

Metallurgical Interaction among BNi-9 and Waspaloy, FSX-414 or 304-Type Stainless Steel under TLP Cycle

Martensitic Stainless Steel Brazing by Using Ag-Cu-Ti as Active Filler Metal Alloys

Thermally Sprayed Nickel-Based Repair Coatings for High-Pressure Turbine Blades: Controlling Void Formation during a Combined Brazing and Aluminizing Process

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