Process for the production of components for combustion engines or turbines

Abstract

The present invention relates to a process for the production of components for combustion engines or turbines, in particular for the production of hollow-valve components, with which for the first time powdery titanium-based alloys, in addition to conventional materials, can be processed into these components. In the process, metal powder and/or metal alloy powder are mixed in a compounder with a binding agent and optionally a flux, the mixture is shaped by injection moulding, the shaped compound is chemically debound, the chemically debound compound is thermally debound at a temperature of less than 450° C. and the chemically and thermally debound compound sintered at a temperature below the melting temperature of the metal and/or metal alloy for the production of the component. The components can be combined with each other in conventional manner by form- and force-locking and also molten joining processes.

1 . Process for the production of components for combustion engines or turbines, in which
 (a) metal powder and/or metal alloy powder are mixed in a compounder with a binding agent and optionally an aggregate material,   (b) the mixture is shaped by injection moulding,   (c) the shaped compound is chemically debound,   (d) the chemically debound compound is thermally debound at a temperature of less than 450° C.,   (e) the chemically and thermally debound compound is sintered at a temperature below the melting temperature of the metal and/or the metal alloy to produce the component.   
   
   
       2 . Process according to  claim 1 , characterized in that the component is a hollow-valve component. 
   
   
       3 . Process according to  claim 2 , wherein the hollow-valve component is a valve cone. 
   
   
       4 . Process according to  claim 2 , wherein the hollow-valve component is a valve disk. 
   
   
       5 . Process according to  claim 1 , characterized in that a titanium alloy is used as metal-alloy powder. 
   
   
       6 . Process according to  claim 5 , characterized in that the titanium alloy contains aluminium and/or vanadium as additional constituents. 
   
   
       7 . Process according to  claim 6 , characterized in that the titanium alloy contains 2 to 10 wt.-% aluminium and/or 2 to 10 wt.-% vanadium based on the overall weight of the alloy. 
   
   
       8 . Process according to  claim 1 , characterized in that the binding agent is selected from the group consisting of: polyamides, polyoxymethylene, polycarbonate, styrene-acrylonitrile-copolymerisate, polyimide, natural waxes and oils, thermosetting plastics, cyanates, polypropylene, polyacetate, polyethylene, ethylene vinyl acetate, polyvinyl alcohol, polyvinyl chloride, polystyrene, polymethyl methacylate, anilines, mineral oils, water, agar, glycerol, polyvinyl butyryl, polybutyl methacrylate, cellulose, oleic acid, phthalates, paraffin waxes, carnauba wax, ammonium polyacrylate, digylceride stearate and oleate, glyceryl monostearate, isopropyl titanate, lithium stearate, monoglycerides, formaldehyde, octanoic acid phosphate, olefin sulphonates, phosphate esters, stearic acid and mixtures of same. 
   
   
       9 . Process according to  claim 1 , characterized in that the proportion by volume of the binder in the mixture is less than 60%. 
   
   
       10 . Process according to  claim 9 , characterized in that the proportion by volume of the binding agent in the mixture is 20% to 50%. 
   
   
       11 . Process according to  claim 1 , characterized in that the mixing in the compounder is carried out at a temperature in the range from 50 to 250° C. 
   
   
       12 . Process according to  claim 1 , characterized in that the injection moulding is carried out at a temperature of the mixture of 90 to 150° C. 
   
   
       13 . Process according to  claim 1 , characterized in that the injection moulding is carried out at a temperature of 400 to 800 bar. 
   
   
       14 . Process according to  claim 1 , characterized in that the chemical debinding is carried out in a hexane bath. 
   
   
       15 . Process according to  claim 1 , characterized in that the chemical debinding is carried out at a temperature of 10 to 65° C. 
   
   
       16 . Process according to  claim 15 , characterized in that the chemical debinding is carried out at a temperature of 30 to 50° C. 
   
   
       17 . Process according to  claim 1 , characterized in that the thermal debinding is carried out at a pressure of 2 to 20 mbar. 
   
   
       18 . Process according to  claim 1 , characterized in that the sintering is carried out at 80% to 90% of the melting temperature of the metal or metal alloy. 
   
   
       19 . Process according to  claim 1 , characterized in that the sintering is carried out under an inert gas atmosphere. 
   
   
       20 . Process according to  claim 19 , characterized in that the inert gas is argon. 
   
   
       21 . Process according to  claim 1 , characterized in that the sintering is carried out under vacuum. 
   
   
       22 . Hollow-valve component which is produced by a process according to  claim 1 , characterized in that it is composed of a titanium-based alloy. 
   
   
       23 . Hollow-valve component according to  claim 22 , characterized in that in addition to titanium the titanium-based alloy contains 2 to 10 wt.-% aluminium and/or 2 to 10 wt.-% vanadium.