Refractory nickel alloys parts joining method

FIELD: machine engineering, possibly restoration of articles operating at large cyclical loads and high temperature values.

SUBSTANCE: method comprises steps of cooling male part in liquefied nitrogen and introducing it into female part. Male part is made of refractory nickel alloy similar to that of female part. After equalizing temperature of assembly, it is heated till recrystallization temperature and subjected to isothermic soaking. It causes creation of structural and phase conversions in assembled parts.

EFFECT: improved quality of joints of parts.

1 ex, 1 tbl

 

The invention relates to mechanical engineering and can be used for welding of holes in the articles of heat-resistant Nickel alloys that operate at high cyclic loads and high temperatures.

There is a method of joining parts with tightness thermal method by cooling one of the joined parts, fixing the relative position and movement in the axial direction. Covered in detail freely introduced into the covering part (as the USSR №867592, 23 P 11/02, 1979).

The disadvantage of this method is the low quality of the connection parts made of heat-resistant Nickel alloys, which works with large cyclic loads and high temperatures.

The closest in technical essence is a way of connecting parts with tightness and heat. Covered in detail is cooled in liquid nitrogen and injected into the covering part. The reduction of diameter (μm) of the landing surface is determined by the formula

Δd =δ+i

where δ - the greatest tension for this connection

i - minimum clearance for free landing during Assembly

(Handbook of engineer-mechanical engineer, edited Aghdashloo, Rcqleneaa, M.: engineering, volume 1, 646-649).

The disadvantage of this method is the low quality of the connection details of heat-resistant Nike is of evich alloys, which works at high cyclic loads and high temperatures.

Goal - improving the quality of the connection parts of heat-resistant Nickel alloys, which works with large cyclic loads and high temperatures.

This objective is achieved in that a method for joining parts made of heat-resistant Nickel alloys, including cooling covered in detail in liquid nitrogen, the introduction of a covering made from a uniform covered with a piece of heat-resistant Nickel alloy, the alignment of the temperature of the obtained compound, subsequent heating of the compounds obtained prior to the recrystallization temperature and the occurrence of structural and phase transformations and isothermal exposure.

The technical solution is designed for welding of holes in turbine blades made of heat-resistant Nickel alloys that operate at high cyclic loads and high temperatures. Usually defects in heat-resistant Nickel alloys cut and make TIG welding metal of the same class with the base metal. The disadvantage of this method is the change of the surface layer of the base metal, experiencing thermal stress.

The proposed technical solution, in the process of diffusion welding there is no external pressure on the welded detail is. Pressure occurs due to structural and phase transformations in welded details.

The method is implemented as follows.

From the homogeneous covering part of the material is made covered in detail. Covered in detail is cooled in liquid nitrogen to a size that provides free fit during Assembly. Covered in detail is injected into the covering part. After equalization of the temperature of the connection is heated to a recrystallization temperature and carry out isothermal exposure. Due to the processes of dissolution γ'-phase in the alloy covered item expands and provides the pressure necessary for diffusion welding of the connection.

Specific example

For welding of cast technological holes in the blade alloy GSI made inserts 03 mm alloy GSI (covered in detail). Prepared inner surface of the casting process vents, cooled insert in liquid nitrogen and introduced into the technological hole. Lined junction temperature. The blade was mounted in a vacuum furnace, heated to 1050°S, has been holding at that temperature for 4 hours. At the same time removed foundry technology hole on existing technology soldering: blade alloy GSI inset alloy VJ, solder VLOOKUP 36, the naked, the EV to soldering temperature 1290° For 20 minutes After cooling the blades cut at the place of insertion and conducted metallographic control.

The table shows the average results of the control.

MethodThe depth of the modified layer in place of welding, mcmThe presence of poresMicrocracks on the border welding
Existing300
Offer10nono

Heating of the welded joint in the area of dissolution γ'-phase ensures the diffusion welding of inserts and high quality boundary of the welded connection.

The proposed method of connection of details improves the quality of the connection parts made of heat-resistant Nickel alloys, which works with large cyclic loads and high temperatures.

The method of joining parts made of heat-resistant Nickel alloys, characterized in that it includes a cooling covered in detail in liquid nitrogen, the introduction of a covering part is made of a homogeneous covered with a piece of heat-resistant Nickel alloy, the alignment of the temperature of the obtained compound, subsequent heating of the compounds obtained prior to the recrystallization temperature and flow structure the situations and phase transformations and isothermal exposure.



 

Same patents:

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2 cl, 4 dwg, 1 ex

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EFFECT: improved quality of joints of parts.

1 ex, 1 tbl

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