Technical Literature

 
Designs
 


Advances in Turbine Airfoil Cooling Designs, Enabled by Improvements in Core Manufacture & Casting Capability (pdf)

  

 
Patents
 
A Brief Chronology of Diffusion Aluminizing Patents

1,155,974  

Aluminizing of Metal Substrates filed in 1911 by Tyco Van Aller

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Abstract

One of the objects of my invention is to treat iron, copper and similar metals so as to produce such a condition upon the surface of the metal or within it that it may be heated to a high temperature for practically an indefinite period without any deleterious effect upon the metal. In carrying out my invention in one aspect I employ the metal aluminum for producing the desired condition. I have found that iron, copper and similar metals when heated with aluminum powder to a suitable temperature and under suitable conditions arrive at such a condition.

 

 
1,770,177
Gas Phase Aluminizing Method
  filed in 1925 by Martin

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Abstract

My invention relates, in general, to a process for coating one metal with another which involves the deposition of the latter metal by dry chemical reaction, and also to apparatus for carrying out this process and to the products resulting from such process. The principal object of my invention resides in the provision of an improved process for coating or depositing one metal on another whereby a metallic object covered by employing such process will be provided with an outer ,surface layer consisting of an alloy of the deposited metal and the metal of the coated object having one or more of certain desirable properties, .such as resistance to oxidation at ordinary temperatures or at high temperatures such as those encountered in furnaces, toughness, malleability, hardness and enhanced appearance, depending upon the metals employed and upon the purposes for which the coated objects are designed to be used. It is practicable by my improved process to cover an object formed of any of a number of different metals, notably either iron, steel, cast iron, copper or nickel, with an alloy of aluminum and the metal of which the object is formed.

 



 
3,544,348
Superalloy Pack Cementation Coating Process (PWA 73)
filed in 1968 by Boone & Goward

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Abstract

An overhaul process for coated gas turbine engine components is described wherein the components are: removed from the engine at or prior to the onset of significant coating penetration as evidenced by the loss of one or more substrate components; recoated in a pack cementation process of high aluminum activity without stripping of the old coating; and are subsequently heat treated to promote the formation of aluminides having an aluminum content less than that corresponding to Ni2Al3.

 









 

3,819,338
Platinum Modified Aluminide Coating
filed in 1971 by Bungardt

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Abstract

Nickel and/or cobalt-based alloys are given a protective coating by diffusing into the surface of the alloy metallic aluminum and one or more metals of the platinum groups.

 

 

 


 

 

4,148,275
“Above the Pack” Coating Process (PWA 275)  filed in 1977 by Benden

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Abstract

Disclosed is an improved apparatus for depositing a coating on the internal surfaces of hollow articles by gas phase deposition. The apparatus typically includes a sheet metal enclosure having a manifold member which defines a first and second chamber therein. The first chamber is adapted to contain a powder mixture for generating a coating gas whereas the second chamber is adapted to house the articles to be coated. The manifold member includes hollow tubes or other connector means extending there through to connect the interior of the articles in gas flow relation to the first chamber where the coating gas is generated. A source external of the enclosure supplies carrier gas to the first chamber at a controlled flow rate via tube means. The carrier gas transports the coating gas generated in the first chamber through the manifold tubes and then into the internal passages of the article to effect deposition. The positive flow of coating gas through the internal passages provides a substantially uniform coating thickness over the entire internal surface area of each article.

 

 

 

 

 

 

 

4,427,720
Vapor Phase Aluminizing
(SNECMA VPA)  filed in 1982 by Gauje

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Abstract

The present invention concerns a vapor phase process for the deposition of at least one protective metal coating on a metal piece. The coating is aluminum, chromium, titanium, or a derivative of these metals or alloys or mixtures. The coating is effected by the reaction of the surface of the metal piece, suitably heated in an enclosure, with a halide compound of the coating metal which is formed by the reaction, in the enclosure, between a chemical halide compound with a donor. The donor consists of the coating metal or an alloy formed in a thin sheet, the surface area being of the same order of magnitude as that of the piece to be coated, located so that the surface area faces the metal piece.

 

 

 

4,382,976
Pulse Aluminizing
  filed in 1982 by Restall

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Abstract

A metallic or ceramic layer is deposited on a component by plasma spraying. This produces a rough, still porous, coating which is poorly bonded at the interface with the substrate. Aluminium or chromium is vapor deposited under pulsating pressure to react with the substrate to form an oxidation resistant coating of Ni Al (intermetallic) or Ni Cr (solid solution) which may include ceramic particles and is aerodynamically smooth.

5,264,245

Chemical Vapor Deposition of Aluminide Coatings (Howmet CVD)  filed 1991 by Punola

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Abstract

A chemical vapor deposition (CVD) method utilizing an apparatus comprising a reactor having a coating chamber at elevated temperature, means for supporting substrates to be coated at different zones in the coating chamber, and means for supplying a gaseous reactant stream to the chamber for distribution to the coating zones in a manner that the stream is heated to substantially different temperatures at different coating zones. Reactivity-altering material is disposed at the coating zones for contact by the reactant stream supplied thereto before the reactant stream contacts a substrate at the zones. The reactivity-altering material includes a composition that differs between coating zones in dependence on the reactant stream temperatures at the coating zones as necessary to alter the reactivity of the reactant (i.e., activity of a particular chemical specie of the reactant stream) stream at the coating zones in a manner to provide substantially the same reactant reactivity at all coating zones. CVD coatings are thereby produced on the substrates that exhibit improved uniformity in composition and thickness from one substrate to the next at the different zones.

 

 

 

6,689,422

Active Element Modified Alumindes via CVD Codeposition  filed in 1994 by Warnes

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Abstract

CVD aluminide coatings including a small concentration of a reactive, gettering element for surface active impurities dispersed therein are formed for improved oxidation resistance. The aluminide coatings are formed by CVD codeposition of Al and the gettering element on the substrate using coating gases for the gettering element generated either outside or inside the coating retort depending on the chlorination temperature needed for the particular gettering element.

 

7,273,662
Gamma-Gamma Prime Aluminide Coating
filed in 2003 by Gleeson

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Abstract

An alloy including a Pt-group metal, Ni and Al in relative concentration to provide a gamma-Ni + gamma′-Ni3Al phase constitution, and a coating including the alloy.

 

A Brief Chronology of Thermal Barrier Coating (TBC) Patents
4,055,705
Yttria Stabilized Zirconia (YSZ) Thermal Barrier Coating
filed in 1976 by Stecura

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Abstract

A coating system which contains a bond coating and a thermal barrier coating is applied to metal surfaces such as turbine blades and which provides both low thermal conductivity and improved adherence when exposed to high temperature gases or liquids. The bond coating contains NiCrAlY and the thermal barrier coating contains a reflective oxide. The reflective oxides ZrO.sub.2 --Y.sub.2 O.sub.3 and ZrO.sub.2 --MgO have demonstrated significant utility in high temperature turbine applications.

 

 

 

4,321,311
Columnar Grained (EB-PVD) Thermal Barrier Coating  with MCrAlY Bond Coat
  filed 1980 by Strangman (pdf)

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Abstract

A coated article and method for producing the coated article are described. The article is coated with a system which provides protection against oxidation and corrosion and which significantly reduces the substrate temperature. An MCrAlY layer is applied to the article to be protected and a columnar grain ceramic is applied by vapor deposition to the MCrAlY coated article. An alumina layer which exists between the MCrAlY layer and the columnar ceramic layer provides for the adherence of the columnar layer to the MCrAlY layer.

 

 

 

5,514,482
Thermal Barrier Coating System with Platinum Aluminide Bond Coat
  filed in 1984 by Strangman (Patent issuance delayed until 1996 by govt secrecy order)

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Abstract

An improvement in a thermal barrier coating for superalloy turbine engine components subjected to high operating temperatures, such as turbine airfoils, e.g., vanes and blades, is disclosed which eliminates the expensive MCrAlY oxidation resistant bond coating underlayer for a columnar grained ceramic thermal barrier coating. In accordance with my present invention, a relatively low cost thermal barrier coating system for superalloy turbine components is provided which utilizes a diffusion aluminide coating layer as the oxidation resistant bonding surface for the columnar grained ceramic insulating coating.

 



 

5,073,433
Thermal Barrier Coating for Substrates and Process for Producing It filed  in 1989 by Taylor

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Abstract

A thermal barrier coating for substrates comprising zirconia partially stabilized by yttria and having a density greater than 88% of the theoretical density with a plurality of vertical macrocracks homogeneously dispersed throughout the coating to improve its thermal fatigue resistance. The invention also discloses a process for producing the thermal barrier coating.

 



 
5,716,720
Thermal Barrier Coating System with Hyperstoichiometric Platinum Aluminide
Bond Coat  filed in 1995 by Murphy

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Abstract

A thermal barrier protected nickel based or cobalt based superalloy component for use in a gas turbine engine includes a thermal barrier coating system having a multi-layered structure. The first bondcoat layer of the thermal barrier coating system comprises a chemical vapor deposited, platinum modified diffusion aluminide layer on the superalloy component (substrate). The diffusion aluminide layer includes an inner diffusion zone proximate the substrate and an outer layer region comprising a platinum modified (platinum-bearing) intermediate phase of aluminum and at least one of nickel and cobalt depending on the superalloy composition. The intermediate phase is a non-ordered solid solution having a range of compositions and is free of other phase constituents. The intermediate phase has an average aluminum concentration in the range of about 18 to about 26% by weight, an average platinum concentration in the range of about 8 to about 35% by weight, and an average nickel concentration in the range of about 50 to 60% by weight and is non-stoichiometric relative to intermetallic compounds of aluminum and nickel, aluminum and cobalt, and aluminum and platinum. An adherent alpha alumina layer is thermally grown on the diffusion aluminide layer and receives an outer ceramic thermal barrier layer deposited thereon.

 

 

 

5,667,663
Thermal Barrier Coating System with a Platinum Modified Gamma-Gamma Prime
Bond Coat filed in 1995 by Rickersby

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Abstract

A ceramic thermal barrier coating layer for a superalloy article is caused to adhere to the superalloy article by applying platinum to the superalloy article and heat treating at a temperature of 1100 C. to 1200 C. for one hour. This causes aluminum to diffuse from the superalloy article into the platinum to form a platinum enriched outer layer which generally includes a platinum enriched gamma phase and a platinum enriched gamma prime phase. An alumina layer is formed between the platinum enriched outer layer and a ceramic coating. The platinum enriched gamma phase and the platinum enriched gamma prime phase in the outer layer reduces the migration of transition metal elements to the ceramic coating to enable a very pure alumina layer to be formed.

 

 

 

Select Superalloy Patents
US 2,381,459A
Vitallium Alloy Turbine Bucket For Exhaust Turbine Superchargers filed in  1941 by Merrick

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Abstract

With the improvement of aircraft and their engines, the necessity for better turbine buckets for exhaust turbine superchargers and better materials for such turbine buckets has become urgent.
The improvement of the present invention consists in forming the bucket by a casting process and of an alloy providing new and advantageous results not equaled by the alloys previously used in making such bucket, and which alloy it would be hopeless to consider for a forged and machined bucket on account of the hardness and difficulty of machining and impracticability of forging the same.
More specifically, the improvement of the present invention consists in providing a cast turbine bucket for exhaust turbine superchargers, such bucket being formed of a cobalt-chromium alloy, and, more particularly, formed of a cobalt, chromium, molybdenum alloy with the constituents combined and proportioned in a manner better to withstand the severe conditions to which such-buckets are subjected.

 

US 3,615,376A
Rene 80 Cast Nickel Base Alloy filed in 1968 by Ross

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Abstract

An improved cast nickel base alloy has a combination of stability, high-temperature stress rupture strength and hot corrosion resistance primarily through control of such phases as sigma, eta, and the carbides. Control is achieved through the balance of the elements Al, Ti, Mo, W, Co, Cr and C in the proper relationships with a Ni base in the substantial absence of Fe.
 
 
 
US 4,108,647A
INCO IN939  Alloys of Nickel, Chromium And Cobalt filed in 1976 by Shaw

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Abstract

The high temperature properties of a nickel-base alloy containing correlated percentages of chromium, cobalt, tungsten, molybdenum, titanium, aluminum, carbon, tantalum, niobium, zirconium, hafnium, boron, yttrium and lanthanum are substantially maintained or improved by further correlation of the percentages of chromium, carbon and boron in the alloy.

 

 
US 4,169,742A
Rene 150 Cast nickel-base alloy article filed in 1977 by Wukusick

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Abstract

A cast nickel-base alloy article having a complex internal passage and a columnar grain structure is provided with an improved combination of castability and mechanical properties through a control of the amount of gamma prime phase and its related phase formers, a careful control of Co and Al along with Hf and a control of the gamma solution strengtheners, particularly Mo and W.
 
 
US 4,209,348A
PWA 1480 Heat Treated Superalloy Single Crystal Article And Process filed in 1978 by Duhl
 

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Abstract

Nickel base superalloy single crystal articles formed of a particular composition and heat treated are described as is the process employed. The resultant articles are substantially free from the grain boundary strengtheners such as carbon, boron, and zirconium and contain only a limited amount of cobalt. As a result of the alloy composition, the alloys have a high incipient melting temperature. The heat treatment process homogenizes the micro-structure, and refines the gamma prime morphology. The alloy is a nickel base alloy containing from about 8 to about 12% chromium, from about 4.5 to about 5. 5% aluminum, from about 1 to 2% titanium, from 3 to 5% tungsten, and from 10 to 14% tantalum. The cobalt content is controlled to fall within the range of 3-7%, and the balance is essentially nickel. The alloy employed in the present invention is free from intentional additions of carbon, boron and zirconium, although obviously these elements may be present as unintentional impurities.

 

US 4,643,782A
 
CMSX-4 Single Crystal Alloy Technology
filed in 1984 by Harris

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Abstract

Single crystal nickel-base superalloy having very fine gamma prime after heat treatment in a temperature range permitting total gamma prime solutioning without incipient melting. Component of the heat treated alloy has exceptional resistance to creep under high temperature and stress, particularly in that part of the creep curve representing one percent or less elongation. The alloy exhibits exceptionally low steady-state creep rate.

 

US 4,719,080A
 
PWA 1484 Advanced High Strength Single Crystal Superalloy Compositions filed in 1985 by Duhl

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Abstract

A superalloy composition and single crystal articles of the composition are described. The broad range is 3-12% Cr, 0-3% Mo, 3-10% W, 0-5% Re, 6-12% Ta, 4-7% Al, 0-15% Co, 0-0.045% C, 0-0.02% B, 0-0.1% Zr, 0-0.8% Hf, 0-2% Nb, 0-1% V, 0-0.7% Ti, 0-10% (Ru+Rh+Pd+Os+Ir+Pt), balance essentially Ni. An equation is presented to select the most useful specific compositions from within this range. An exemplary preferred composition is 5.0% Cr, 10.0% Co, 2.0% Mo, 6.0% W, 3.1% Re, 5.6% Al, 9.0% Ta, 0.1% Hf, balance essentially Ni.
 
 
 
US 5,173,255A
 
DS Rene 142 Cast Columnar Grain Hollow Nickel Base Alloy Articles filed in 1991 by Ross

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Abstract

One form of an improved cast, hollow, columnar grain nickel base alloy article is provided with outstanding elevated temperature stability as represented by oxidation resistance, an improved combination of longitudinal and transverse stress rupture properties, and a thin wall of less than about 0.035 inch, substantially free of cracks. Described is a heat treatment in combination with an alloy for providing such an article.

 

US 5,366,695A
 
CMSX-10 Single Crystal Nickel-based Superalloy filed in 1992 by Erickson

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Abstract

This invention relates to a nickel-based superalloy comprising the following elements in percent by weight: from about 5.0 to about 7.0 percent rhenium, from about 1.8 to about 4.0 percent chromium, from about 1.5 to about 9.0 percent cobalt, from about 7.0 to about 10.0 percent tantalum, from about 3.5 to about 7.5 percent tungsten, from about 5.0 to about 7.0 percent aluminum, from about 0.1 to about 1.2 percent titanium, from about 0 to about 0.5 percent columbium, from about 0.25 to about 2.0 percent molybdenum, from about 0 to about 0.15 percent hafnium, and the balance nickel+incidental impurities, the superalloy having a phasial stability number N.sub.v3B less than about 2.10.

 

 
US 5,399,313A
 
Rene N4 Nickel-based Superalloys For Producing Single Crystal Articles Having Improved Tolerance To Low Angle Grain Boundaries filed in 1992 by Ross

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Abstract

There is provided by the present invention nickel-base superalloys for producing single crystal articles having improved tolerance to low angle grain boundaries and an improved balance between cyclic oxidation and hot corrosion resistance. The improved tolerance arises from the discovery that nickel-base superalloys suitable for casting as single crystal articles can be improved by the addition of small, but controlled, amounts of boron and carbon, and optionally hafnium, and is manifested principally by improved grain boundary strength. As one result of this increased grain boundary strength, grain boundary mismatches far greater than the 6 limit for prior art single crystal superalloys can be tolerated in single crystal articles made from the nickel-base superalloys of this invention. This translates, for example, into lower inspection costs and higher casting yields as grain boundaries over a broader range can be accepted by visual inspection techniques without resort to expensive X-ray techniques. These alloys are especially useful when directionally solidified as hot-section components of aircraft gas turbine engines, particularly rotating blades and stationary vanes. The superalloy contains by weight percent, 7-12 Cr, 5-15 Co, 0.5-5 Mo, 3-12 W, 2-6 Ta, 2-5 Ti, 3-5 Al, 0-2 Cb, 0.1-0.2 Hf, 0. 05-0.07 C, 0.002-0.05 B, and nickel.

 

US 6,074,602A
 
Rene N5 Property Balanced Nickel-base
Superalloys For Producing Single
Crystal Articles
 Originally filed in 1985 by
Wukusick , re-filed in 1994 issued in 2000

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Abstract

The present invention is directed to the achievement of increased gas turbine engine efficiencies through further improvements in nickel-base superalloys used to make parts and components for gas turbine engines. The present invention comprises nickel-base superalloys for producing single crystal articles having a significant increase in temperature capability, based on stress rupture strength and low and high cycle fatigue properties, over single crystal articles made from current production nickel-base superalloys. Further, because of their superior resistance to degradation by cyclic oxidation, and their resistance to hot corrosion, the superalloys of this invention possess a balance in mechanical and environmental properties which is unique and has not heretofore been obtained.

 

US 6,231,692B1
 
 
Nickel Base Superalloy With Improved
Machinability And Method Of Making Thereof
(Rene 80 Mod. For IGT)
filed in 1999 by Vogt

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Abstract

Machineable nickel base alloy casting, consisting essentially of, in weight %, about 12.5% to 15% Cr, about 9.00% to 10.00% Co, about 3.70% to 4.30% Mo, about 3.70% to 4.30% W, about 2.80% to 3.20% Al, about 4.80% to 5.20% Ti, about 0.005% to 0.02% B, up to about 0.10% Zr, and balance essentially Ni and carbon below about 0.08 weight % to improve machinability while retaining alloy strength properties after appropriate heat treatment.
 
 
 
Select Investment Casting Technology Patents
US 3,260,505A
Directional Solidification (DS) Casting Process filed in 1964 by VerSnyder

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Abstract

The blades of the present invention have an elongated, columnar macro-grain structure with substantially unidirectional crystals aligned substantially parallel to the axis of the cast blade; that is, with a columnar structure in the alloy of the blade. The grain boundaries of the alloy of the cast blade are oriented so as to be substantially parallel to the principal stress axis of the blade, and there is an almost complete elimination of grain boundaries normal to this stress axis.

 

US 3,494,709 A
Single Crystal Casting Process filed in 1964 by Piearcey

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Abstract

A cast metallic alloy part for a gas turbine power plant is formed as an elongated single crystal of a strong, heat resistant and corrosion-resistant alloy having a face-centered cubic crystal structure, said crystal being oriented with its <001> direction being less than 20 degrees from the elongated axis of the crystal, said single crystal part having an air-foil portion and a laterally enlarged integral base portion, the whole being a single integral crystal.
The present invention relates to a novel and improved process and mold for the formation of elongated shaped objects comprising a single crystal oriented in a particularly desirable direction and to an apparatus useful in carrying out the process, as well as to novel and such improved single-crystal blades and vanes for a gas turbine engine, especially those blades and vanes formed from certain nickel-based alloys.

 

US 3,763,926A
Liquid Metal Cooling Apparatus for Casting of Directionally Solidified Articles filed in 1971 by Tschinkel

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Abstract

Apparatus for casting directionally solidified articles either columnar grained or single crystal in which the rate of solidification is controlled by gradual immersion or submergence by a liquid coolant.
One of the principal features of the present invention is the very rapid heat removal from the mold in conjunction with a sharp transition between the hot and cold surroundings in order to maintain a high thermal gradient and also a high growth rate for making the cast article. Another feature is the use of a liquid coolant into which the mold is immersed or in which the mold is submerged gradually for the rapid extraction of heat from the mold, thereby obtaining the desired grain growth within the mold. Another feature is the use of this liquid coolant to circulate around all of the several molds in a multiple mold casting so that the heat removal from the several molds will be the same and, accordingly, the desired grain growth will be obtained within all of the molds. A particular feature of the invention is the control of the dendritic growth within the casting in such a way as to significantly reduce the distance between the dendrites and thereby minimize the segregation of the microconstituents in the interdendritic regions.
 
 
US 5,921,310A
Gas Jet Process For Producing A Directionally Solidified Casting filed in 1997 by Kats

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Abstract

The process serves to produce a directionally solidified casting (20) and uses an alloy located in a casting mold (12). The casting mold (12) is guided from a heating chamber (4) into a cooling chamber (5). The heating chamber (4) is here at a temperature above the liquidus temperature of the alloy, and the cooling chamber (5) is at a temperature below the solidus temperature of the alloy. The heating chamber (4) and the cooling chamber (5) are separated from one another by a baffle (3), aligned transversely to the guidance direction, having an opening (7) for the casting mold (12). When carrying out the process, a solidification front (19) is formed, beneath which the directionally solidified casting (20) is formed. The part of the casting mold (12) which is guided into the cooling chamber (5) is cooled with a flow of inert gas. As a result, castings (20) which are practically free of defects are achieved with high throughput times.
 
 
   
Solid Particle Erosion  
   

 



 

 



 

 

 

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