Method and device for making intricately-shaped axisymmetric parts from hardly deformable polyphase alloys

Abstract

A method for making an intricately-shaped axisymmetric part having a central portion and a peripheral portion, comprises simultaneously rotating a blank structure fixed on a shaft and forming a peripheral portion of the blank using a forming tool having at least three degrees of freedom (i) at a temperature above 0.4 the blank melting point but below the temperature of secondary recrystallization, (ii) at a rate of from 10 −3 to 10 2 s −1 , and (iii) for a rotation period to effect stress relief in the portion being formed. A device for making intricately-shaped axisymmetric part having a central portion and a peripheral portion, comprising an axial blank structure fixing and rotating unit including a fixture for interchangeably installing a mandrel including a built-up mandrel; at least one roll with a carrier; actuating mechanism for rotating and displacing the roll relative to a blank structure fixed by the unit; a furnace for heating the blank structure fixed by the unit, the furnace having a movable portion disposed around a window for introducing the roll into the furnace; wherein the movable portion of the furnace is axially movable together with the roll over an entire working stroke length of the roll.

What is claimed is:  
     
         1 . A method for making an intricately-shaped axisymmetric part having a central portion and a peripheral portion, comprising: 
 simultaneously rotating a blank structure fixed on a shaft and forming a peripheral portion of the blank using a forming tool having at least three degrees of freedom (i) at a temperature above 0.4 the blank melting point but below the temperature of secondary recrystallization, (ii) at a rate of from 10 −3  to 10 2  s −1 , and (iii) for a rotation period to effect stress relief in the portion being formed.    
     
     
         2 . The method of  claim 1 , wherein at least a part of the peripheral blank portion has an outside diameter exceeding the diameter of a finished part or an inside diameter less than the diameter of a finished part.  
     
     
         3 . The method of  claim 1 , wherein the blank structure has not been preconditioned for superplastic deformation.  
     
     
         4 . The method of  claim 1 , comprising preconditioning the blank structure for superplastic deformation.  
     
     
         5 . The method of  claim 1 , wherein forming the blank comprises reducing the blank structure peripheral portion by rolling in a direction toward its central portion.  
     
     
         6 . The method of  claim 1 , comprising forming an aluminum blank structure for a period not in excess of 0.25 s.  
     
     
         7 . The method of  claim 1 , comprising forming a titanium blank structure or heat resistant nickel alloy blank structure for a period of 0.25 to 100 s.  
     
     
         8 . The method of  claim 1 , comprising forming a coarse-grained blank structure for a period of 0.5 to 100 s.  
     
     
         9 . The method of  claim 1 , comprising forming a fine-grained blank structure for a period of 10 to 50 s.  
     
     
         10 . The method of  claim 1 , comprising forming a submicrocrystalline blank structure for a period of 0.25 to 10 s.  
     
     
         11 . The method of  claim 1 , comprising forming the blank structure in a number of steps determined by the preformed condition and material of the blank structure.  
     
     
         12 . The method of  claim 1 , comprising preparing the blank structure for superplastic deformation and preforming the blank structure into the shape of a sleeve, wherein forming the peripheral portion is completed in a single step.  
     
     
         13 . The method of  claim 1 , comprising preparing both a central portion and the peripheral portion of the blank structure for superplastic deformation and forming a sleeve-shaped blank in a first step and forming the shaped part from the blank in a further step.  
     
     
         14 . The method of  claim 1 , comprising performing a coarse-grained blank structure into a central portion and a thin-walled peripheral projection and forming the preformed blank into a sleeve-shaped blank being prepared in a first step and subjecting the sleeve-shaped blank to 50-75% reduction under superplaticity temperature and deformation rate conditions.  
     
     
         15 . The method of  claim 1 , comprising forming in a first step effected by reversal roll motion.  
     
     
         16 . The method of  claim 1 , comprising using a forming mandrel to form a part having varying thickness and diameter dimensions.  
     
     
         17 . The method of  claim 1 , comprising forming in a first step effected by reversal roll motion and using a forming mandrel to form an interior surface of the blank structure.  
     
     
         18 . The method of  claim 1 , comprising forming in a first step effected by reversal roll motion and using a forming mandrel to form an exterior surface of the blank structure.  
     
     
         19 . The method of  claim 1 , comprising forming in a first step effected by reversal roll motion and using a built-up forming mandrel in a further forming step.  
     
     
         20 . The method of  claim 1 , comprising forming in a first step effected by reversal roll motion and using a forming mandrel heated within a superplasticity range of the blank structure in a further forming step.  
     
     
         21 . The method of  claim 1 , comprising preparing the blank structure for superplastic deformation and preforming the blank structure into the shape of a sleeve having a monotonically narrowing shape, wherein forming the peripheral portion is completed in a single step.  
     
     
         22 . The method of  claim 1 , comprising preparing the blank structure for superplastic deformation and forming the blank structure into the shape of a sleeve having a monotonically narrowing shape, wherein forming the peripheral portion utilizes a single roll and a forming mandrel having an outside diameter equal to a minimum inside diameter of the blank peripheral portion.  
     
     
         23 . The method of  claim 1 , wherein forming comprises using a first roll to form on a first side of the blank structure in a first step and using the first roll and a second roll at an opposite side in a second step.  
     
     
         24 . The method of  claim 1 , comprising forming a fine-grained heat-resistant nickel alloy blank stricture at a temperature from the deformation temperature to a temperature of superplascity of the structure.  
     
     
         25 . A device for making intricately-shaped axisymmetric part having a central portion and a peripheral portion, comprising 
 an axial blank structure fixing and rotating unit including a fixture for interchangeably installing a mandrel including a built-up mandrel;    at least one roll with a carrier;    actuating mechanism for rotating and displacing the roll relative to a blank structure fixed by the unit;    a furnace for heating the blank structure fixed by the unit, the furnace having a movable portion disposed around a window for introducing the roll into the furnace;    wherein the movable portion of the furnace is axially movable together with the roll over an entire working stroke length of the roll.    
     
     
         26 . The device of  claim 25 , wherein the blank structure fixing and rotating unit comprises a shaft and sleeve for imparting torque to the blank structure.  
     
     
         27 . The device of  claim 25 , wherein the roll carrier further comprises a heat shield.  
     
     
         28 . The device of  claim 25 , comprising two rolls disposed on the opposite sides of a wall of the blank structure.  
     
     
         30 . A method for making a part having a central portion and a peripheral portion, comprising: 
 preconditioning a blank structure for superplastic deformation;    forming the blank structure into the shape of a sleeve having a monotonically narrowing shape in a first step, forming a complete peripheral portion of the sleeve in a single second step (i) at a temperature above 0.4 the blank melting point but below the temperature of secondary recrystallization, (ii) at a rate of from 10 −3  to 10 2  s −1 , and (iii) for a rotation period to effect stress relief in the portion being formed.    
     
     
         31 . The method of  claim 30 , comprising using a roll and a mandrel to form the sleeve shape in the first step and forming the complete peripheral portion in the single second step by use of two rolls disposed on opposite sides of a forming wall of the peripheral portion.