JP4647604B2 - Method for producing parts containing nickel-based alloy, and parts produced by the method - Google Patents

Description

Field of Invention

The present invention relates to a method for manufacturing a part containing a nickel-based alloy, and a part manufactured by the method. This solution makes it possible to produce parts with very different shapes and in different three-dimensional geometric structures. The parts thus produced can exhibit a porous structure or can comprise such a porous structure.

  Of course, various parts can be produced with nickel-based alloys known per se, which can be achieved mainly by known molding methods. For example, such a part can be manufactured as a cast part, which can be subsequently cold worked, or optionally hot worked again.

  However, problems arise due to the mechanical properties of such nickel-based alloys, especially during such cut forming processes.

  Furthermore, it has been proposed to deform nickel parts using sintering methods, in which case the formation of solid solutions or intermetallic phases (preferably to improve the properties of such parts). The formation of NiAl) should be achieved by sintering. However, particularly in this form, only the thermal properties of such parts could be improved, and as a result, the mechanical properties have not been improved in the desired form.

Detailed description of the invention

Accordingly, it is an object of the present invention to provide a method by which parts of very different shapes and improved mechanical properties can be produced from nickel-based alloys.

  According to the invention, this object is achieved by a method comprising the features of claim 1. The part manufactured in this way has the features of claims 17 and 18.

  Advantageous embodiments and improvements of the invention can be achieved with the features described in the dependent claims.

  To manufacture parts from nickel-based alloys, the procedure of the present invention is performed such that a surface coating is applied to a substrate core made of pure nickel or nickel-based alloys at least in certain areas. This surface coating is formed from a binder as well as a metal powder. The metal powder used according to the present invention comprises at least 20% by weight of nickel content, in addition to the additional alloying elements described below.

  A substrate core made of a nickel-based alloy should contain at least 20% by weight of nickel.

  The metal powder used according to the present invention may be a powder of the respective nickel-based alloy, but may also be a powder mixture of each alloy-forming element and nickel, preferably subjected to high energy grinding.

  According to the invention, the substrate core with the surface coating is subsequently subjected to a stepwise heat treatment. In that case, the binder is expelled from the substrate core in the first step. After expelling the binder, sintering of the metal powder is achieved. During sintering, sintering-melting of the nickel base core and / or solid surface coating formed from the nickel-based alloy proceeds.

  When a nickel-based alloy base core is used as a semi-finished product, the amount of nickel contained in the metal powder should be less than the nickel content in the base core material.

  However, the heat treatment, at least such sintering, should be carried out at a temperature above 1000 ° C. in a reducing or inert atmosphere, preferably in a hydrogen atmosphere.

  As a substrate core, the geometry of the part to be finally produced is such that no final remechanical processing of the shape is required or only minimal remechanical processing is required. Substrate cores that already have a morphology can be used.

  However, in the solution of the present invention, the substrate core can also be used in the form of a porous semi-finished product, preferably having a porous structure, sometimes also referred to as a foam.

  In particular, in the production of such porous foam structures, surface coatings should be formed with suspensions / dispersions, optionally made from binders, metal powders and additional solvents, or made from liquids. It is.

  Of course, it is also possible to deposit such a suspension / dispersion on a non-porous structured substrate core.

  Such a substrate core having a porous structure is completely immersed in such a suspension / dispersion and subsequently compressed such a substrate core filled with the suspension / dispersion The suspension / dispersion can then be removed from the pores so that only the web is wet.

  Subsequently, stepwise heat treatment can be performed.

  However, when manufacturing parts in the form of porous foam, it is also possible to use a binder with an appropriate viscosity, optionally using a solvent, to wet the surface of the porous structure of such a substrate core. In this case, a grouting treatment can also be carried out here in order to remove excess binder from the pores.

  Subsequently, each metal powder is deposited on the wet surface. At this time, the metal powder can be more uniformly distributed by vibration. This is followed by a stepwise heat treatment again.

  After forming the surface coating, the substrate core, preferably a substrate core having a porous structure, can also be deformed before the stepwise heat treatment.

  For example, the bending can be performed according to a determined minimum bending radius. For example, a hollow cylindrical part or a helical part can be produced.

  However, the composite material member can also be easily manufactured by the solution of the present invention. In that case, the surface coating can be applied to at least one surface area of the substrate core.

  This surface area can then be brought into contact with at least one further substrate core, in which case the adhesive effect of the binder can be used to advantage. Following this, a heat treatment is carried out, in which case a closure is formed by an adhesive force type connection of the respective substrate cores.

  However, it is also possible to apply a surface coating to the surface areas of two or more substrate cores to be connected together by a partition by adhesive force, bring them into contact, and then connect to the partition by adhesive force by heat treatment.

  In this way, for example, a composite material member having a complex geometrical structure comprising a lower cutout and a cavity can be produced without the need for subsequent molding.

  However, a composite material member formed from a base material core having a dense structure and a base material core having a porous structure can also be manufactured.

  The metal powder used in the present invention preferably contains at least 50% by weight of carbon, molybdenum, iron, cobalt, niobium, titanium, aluminum, boron, zirconium, manganese, silicon, and at least 50% by weight of nickel. Lanthanum can also be included.

  However, the properties of the parts produced according to the invention can also be changed by forming various surface coatings on the limited surface area of the substrate core in addition to the respective powder composition. .

  This is on the one hand related to the respective thickness of the surface coating which can also be achieved by repeated application in different forms, on the other hand, the surface in which the content of the metal powder, the composition of the metal powder and the particle size of the metal powder are different. It is also possible to provide a locally different consistency of the coating.

  As a result, locally different properties can be achieved on such parts manufactured according to the present invention.

  The solution according to the invention makes it possible to produce parts with a progressively changing alloy composition starting from the surface. For example, parts using a core made of pure nickel, still having a core area of pure nickel after sintering, and the content of additional alloy elements gradually changing / increasing towards the respective surface Can be manufactured.

  With the production of the composite material as already mentioned, the alloy composition can also be gradually changed in the joining area formed by using partitions with adhesive force connections.

  Parts made according to the present invention have higher ductility, creep resistance and strength compared to parts made only from nickel, and this situation is also true for comparison with nickel aluminides.

  The oxidation tendency compared to nickel parts can also be reduced.

  These parts achieve a thermal stability up to 1000 ° C., and parts made according to the invention, especially those with a porous structure, are also used in applications where nickel aluminide foams cannot be used, for example due to brittleness it can.

  The parts produced according to the invention can be used in particular with higher dynamic loads.

  In the following, the present invention will be described as an example.

Embodiment 1
A base core made of nickel and having a size of 300 mm × 150 mm × 1.9 mm and a porosity of 94% was immersed in 50 ml of a 1% aqueous solution of polyvinylpyrrolidone. Subsequently, pressing was performed on the absorbent pad to remove the binder from the pore cavities so that only the porous web was wet.

  Following this, the porous substrate core wetted with the binder was fixed in a vibrator and sprinkled with metal powder. As a result of the vibration, a uniform distribution of the metal powder is achieved on the surface of the substrate core wetted with the binder, while maintaining the open porosity of the structure.

  The composition of the metal powder was as follows: carbon 0.1% by weight, chromium 22.4% by weight, molybdenum 10.0% by weight, iron 4.8% by weight, cobalt 0.3% by weight, niobium 3.8% by weight and nickel 58 .6% by weight. Such a metal powder is commercially available under the trade name “Inconel 625”.

  The substrate core surface coated with metal powder and binder was rolled into a cylindrical object. At that time, the adhesion of the metal powder is ensured by the binder.

  This was followed by a stepwise heat treatment, in which the first step was performed in a drying furnace and in a water atmosphere. The temperature was increased while maintaining a heating rate of 5 K / min. Binder elimination started at about 300 ° C and was completed at 600 ° C. A retention time of about 30 minutes should be ensured in order to completely release the binder.

  Subsequently, sintering was performed at a temperature of 1150 ° C. to 1250 ° C. for a holding time of about 30 minutes.

  The part thus manufactured is made of a nickel-based alloy, and the composition on the surface thereof is at least approximately equal to the composition of the metal powder used. The porosity is 91%. In air, the part was oxidation resistant up to a temperature of 1000 ° C. and also had high strength, creep resistance and toughness. After sintering, this porous foam structure was still capable of limited deformation given the special minimum bend radius.

Embodiment 2
A corrugated sheet of pure nickel, size 200 mm × 200 mm × 0.15 mm, was used as the substrate core.

  The surface coating of this substrate core was formed from 18 ml of a 6% aqueous solution of polyvinylpyrrolidone and a metal powder whose composition is equivalent to the metal powder used in embodiment 1.

  The suspension produced from the metal powder and the binder was vigorously stirred and then sprayed from both sides onto the substrate core with compressed air. The surface coating had a thickness of 150 μm. After drying for 1 minute, the layer had a sufficiently large green strength so that a stepwise heat treatment could be performed as in embodiment 1.

  The final part was made of a nickel-based alloy, and the alloy composition on the surface thereof was almost equal to the alloy composition of the metal powder used. In air, the part was oxidation resistant up to a temperature of 1000 ° C. High strength, creep resistance and toughness were increased compared to a substrate core made from pure nickel.

Claims (13)

A method for manufacturing a component containing a nickel-based alloy,
A nickel or we produced porous foam substrate on the core, a binder, and carbon, chromium, molybdenum, iron, cobalt, niobium, titanium, aluminum, boron, zirconium, manganese, silicon and / or lanthanum And depositing a surface coating with an alloy powder comprising at least 20% by weight nickel , wherein the foam is coated with the binder, and the coated foam is pressed to form the binder. Depositing the alloy powder on the foam removed from the pores of the foam and wetted with the binder, and during and / or after depositing the alloy powder, vibrating the foam;
After deforming the coated substrate core or the foam,
Subjecting the coated substrate core to a stepwise heat treatment, wherein the stepwise heat treatment includes a heat treatment for driving out the binder, followed by a heat treatment for sintering the alloy powder; The alloying of the nickel base core and / or solid surface coating formed from the nickel-based alloy proceeds.   The method according to claim 1, wherein the nickel content is lower than the nickel content in the base core formed from the nickel-based alloy.   3. A method according to claim 1 or 2, wherein the foam is coated with a suspension / dispersion formed from the binder and the alloy powder followed by the stepwise heat treatment.   4. The method of claim 3, wherein the coated foam is pressed and the suspension / dispersion is removed from the pores of the foam. The surface of at least one substrate core is coated with a suspension / dispersion, the coated surface is brought into contact with the surface of at least one second substrate core, and the heat treatment is performed to form the substrate. forming an adhesion type connection of the core, the method according to any one of claims 1-4. 6. A method according to any one of the preceding claims, wherein the respective surface of the second or another substrate core is also coated. Performing a plurality of coating on said surface of said substrate core, the method according to any one of claims 1-6. Area of the substrate core, different coated in the form, the method according to any one of claims 1-7. The method according to claim 5 or 6 , wherein the coating is carried out with the suspension / dispersion of different consistency and / or of different layer thickness. It said include powders of nickel and other alloying elements, using the powder mixture was subjected to high energy milling method according to any one of claims 1-9. The method according to any one of claims 1 to 10 , wherein the sintering is carried out in a reducing or inert atmosphere at a temperature above 1000 ° C. Alloy composition which changes gradually starting from the surface is formed, the method according to any one of claims 1 to 11. At least inside of the joining zone of the partition by adhesion type connection, gradually changing the alloy composition is formed, the method according to any one of claims 1 to 11.