Method for working billets of metals and alloys

Abstract

A multiple stage method for plastic working of a blank, comprises applying a torsional loading to the blank at a first stage in multiple steps at loading conditions selected to effect microstructure transformation; and applying a tensile or compression loading at a second stage subsequent to the torsional loading stage. An article, comprises a hollow blank with a hollow core emplaced within the blank and expanded by pressurized fluid contained within the core interior and a sheath encompassing the blank in a blank to sheath contact along a blank lateral surface that prevents the sheath and blank from displacement relative to each other.

1 . A multiple stage method for plastic working of a blank, comprising: 
 applying a torsional loading to the blank at a first stage in multiple steps at loading conditions selected to effect microstructure transformation; and    applying a tensile or compression loading at a second stage subsequent to the torsional loading stage.    
     
     
         2 . The method of  claim 1 , wherein the steps and loading conditions are selected to effect microstructure transformation in the course of a heat-treatment between steps.  
     
     
         3 . The method of  claim 1 , wherein the steps and loading conditions are selected to effect microstructure transformation in the course of a deforming selected from the torsional loading, tensile loading and compression loading.  
     
     
         4 . The method of  claim 1 , comprising applying the loadings in a number of operating stages so that a microstructure transformation is provided at a first stage and a wrought layer deformation in a subsequent operating stage proceeds under conditions of superplasticity.  
     
     
         5 . The method of  claim 1 , comprising selecting a number of operating stages and types of loadings according to a configuration of a primary blank, grain size of the primary blank and a desired configuration of a final blank.  
     
     
         6 . The method of  claim 1 , comprising selecting a number of operating stages and types of loadings according to a preset grain size distribution over a blank cross-section.  
     
     
         7 . The method of  claim 1 , comprising working a titanium blank at a deformation heat-treatment comprising cooling the blank until a temperature of a next step is attained that is equal to a temperature of a preceding step.  
     
     
         8 . The method of  claim 1 , comprising working a titanium blank at a deformation heat-treatment comprising cooling the blank until a temperature of a next step is attained that is below a temperature of a preceding step followed by heating to the temperature of the next step.  
     
     
         9 . The method of  claim 1 , comprising working a titanium blank at a deformation heat-treatment comprising cooling the blank to room temperature followed by heating to a temperature of a next step.  
     
     
         10 . The method of  claim 1 , comprising working a titanium blank at deformation ratio and temperature-and-rate conditions selected to effect dynamic recrystallization in beta-phase and heat-treating to provide phase transformation, wherein the blank is heated to a temperature exceeding a temperature of blank working at a preceding step and subsequently cooling to a temperature of a next step.  
     
     
         11 . The method of  claim 1 , comprising working a titanium blank at deformation ratio and temperature-and-rate conditions selected to effect static recrystallization in beta-phase, recrystallization annealing between steps and heat-treating to provide phase transformation, wherein the blank is heated to a temperature exceeding a temperature of blank working at a preceding step and subsequently cooling to a temperature of a next step.  
     
     
         12 . The method of  claim 1 , comprising working the blank at a first stage deformation temperature and working the blank at a subsequent stage below the deformation temperature of the first stage.  
     
     
         13 . The method of  claim 1 , comprising effecting deformation in two stages wherein, an amount of first stage deformation is selected to provide a value of microstructure reduction determined from the relationship  
       
         
           
             
               
                 v 
                 1 
               
               ≥ 
               
                 
                   v 
                   0 
                 
                  
                 
                   
                     σ 
                     2 
                   
                   
                     ( 
                     
                       
                         σ 
                         1 
                       
                       + 
                       
                         σ 
                         2 
                       
                     
                     ) 
                   
                 
               
             
           
           
           
               
           
         
       
       where V o  is the volume of the entire blank; 
 V 1  is the volume of the transformed blank portion;  
 σ 1  is the flow stress of a material having a microcrystalline structure;  
 σ 2  is the flow stress of the material in the primary blank; furthermore, the temperature of a second stage is selected to be not in excess of the first deformation stage.  
 
     
     
         14 . The method of  claim 1 , further comprising applying an axial loading component to the blank in at least a third stage.  
     
     
         15 . The method of  claim 1 , wherein the blank is an axisymmetric blank in the shape of a rod having a cross-sectional dimension that is smaller than a preset grain size.  
     
     
         16 . The method of  claim 1 , wherein the blank is a washer-shaped blank with a smaller height dimension than a preset grain size.  
     
     
         17 . The method of  claim 1 , wherein the blank is a washer-shaped blank and the second stage comprises applying a uniaxial compression.  
     
     
         18 . The method of  claim 1 , wherein the first stage comprises applying a compressional loading with the torsional loading.  
     
     
         19 . The method of  claim 1 , wherein the first stage comprises applying a tension loading with the torsional loading.  
     
     
         20 . The method of  claim 1 , wherein the first stage comprises alternately applying a torsion loading and an axial loading.  
     
     
         21 . The method of  claim 1 , wherein the first stage comprises alternately applying a monotonic torsion loading and an axial loading.  
     
     
         22 . The method of  claim 1 , wherein the first stage comprises alternately applying a torsion loading and a monotonic axial loading.  
     
     
         23 . The method of  claim 1 , wherein the first stage comprises monotonic two-component loading wherein a ratio between an axial component of the loading force and the torsional component is not in excess of 0.2.  
     
     
         24 . The method of  claim 1 , wherein the second stage comprises applying a combined compression and torsion loading.  
     
     
         25 . The method of  claim 1 , wherein the second stage comprises applying a combined tension and torsion loading.  
     
     
         26 . A multiple stage method for plastic working of a titanium blank, comprising: 
 working a titanium blank by applying a torsional loading to the blank at a first stage in multiple steps at loading conditions selected to effect microstructure transformation; and applying a tensile or compression loading at a second stage subsequent to the torsional loading stage, wherein the working is at a deformation ration and under temperature-and-rate conditions selected to effect dynamic recrystallization in beta-phase; and    heat treating to provide phase transformation.    
     
     
         27 . The method of  claim 26 , comprising working a titanium blank at deformation ratio and temperature-and-rate conditions selected to effect static recrystallization in beta-phase, recrystallization annealing between steps and heat-treating to provide phase transformation.  
     
     
         28 . The method of  claim 26 , comprising working a (α+β) titanium blank, at a deformation temperature not exceeding [T Ac3 −(20÷30)]° C.  
     
     
         29 . The method of  claim 26 , comprising working an alpha or pseudo-alpha titanium at a constant deformation temperature that ranges within T Ac3 +T Ar3  for the titanium being worked.  
     
     
         30 . The method of  claim 26 , comprising working a titanium blank at a deformation heat-treatment comprising cooling the blank at a specified rate that provides for a direct phase transformation according to a diffusion mechanism.  
     
     
         31 . The method of  claim 26 , comprising working a titanium blank at a deformation heat-treatment comprising cooling the blank at a specified rate that is not in excess of martensite transformation in the beta-phase and corresponding to a maximum intensity of forming annealing twins in the alpha phase.  
     
     
         32 . The method of  claim 26 , comprising working a titanium blank at a deformation heat-treatment comprising cooling the blank until the temperature of a next step is attained.  
     
     
         33 . The method of  claim 26 , comprising working a titanium blank at a deformation heat-treatment comprising cooling the blank until the temperature of a next step is attained that is below the temperature of a preceding step.  
     
     
         34 . The method of  claim 26 , comprising working a titanium blank at deformation ratio and temperature-and-rate conditions selected to effect dynamic recrystallization in beta-phase and heat-treating to provide phase transformation, wherein the blank is wrought at a variable temperature.  
     
     
         35 . The method of  claim 26 , comprising working a titanium blank at deformation ratio and temperature-and-rate conditions selected to effect static recrystallization in beta-phase, recrystallization annealing between steps and heat-treating to provide phase transformation, wherein the blank is wrought at a variable temperature.  
     
     
         36 . The method of  claim 26 , comprising working a (α+β) titanium blank, at a deformation temperature not exceeding [T Ac3 −(20÷30)]° C., wherein the blank is wrought at a variable temperature.  
     
     
         37 . The method of  claim 26 , comprising working a titanium blank having an original cast structure, comprising a first stage working preceded by a preconditioning step to provide dynamic recrystallization in the beta phase and heat-treating to cause reverse phase transformation.  
     
     
         38 . A multiple stage method for plastic working of a blank, comprising: 
 working the blank by applying a torsional loading to the blank at a first stage in multiple steps at loading conditions selected to effect microstructure transformation; and applying a tensile or compression loading at a second stage subsequent to the torsional loading stage,    wherein the blank is deformed by working in a uniaxial tension sheath of a material, capable of undergoing superplastic deformation, wherein the sheath is in contact along the lateral surface of the blank to prevent displacement between the sheath and blank during working.    
     
     
         39 . The method of  claim 38 , comprising placing the blank within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained that prevents the sheath and blank from displacement relative to each other during the working.  
     
     
         40 . The method of  claim 38 , comprising placing the blank within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained that prevents the sheath and blank from displacement relative to each other and working the blank within the sheath according to said first and second stage.  
     
     
         41 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank and subjecting the blank and core to plastic deformation according to said first and second stage.  
     
     
         42 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank and subjecting the blank and core to plastic deformation according to said first and second stage, wherein said core comprises a material that is deformable under conditions of superplasticity at the plastic deformation temperature and rate.  
     
     
         43 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank and placing the blank and core within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained that prevents the sheath and blank from displacement relative to each other and working the blank with core within the sheath according to said first and second stage.  
     
     
         44 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core of hollow construction within the blank and placing the blank and core within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained that prevents the sheath and blank from displacement relative to each other and working the blank with core within the sheath according to said first and second stages.  
     
     
         45 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core of solid construction within the blank and placing the blank and core within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained that prevents the sheath and blank from displacement relative to each other and working the blank with core within the sheath according to said first and second stages.  
     
     
         46 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank, expanding the core by pressure feeding of a working fluid into the core interior space and working the blank with core according to the first and second stages.  
     
     
         47 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank, interposing a material having viscous-flow properties between the blank and the core and working the blank with core according to the first and second stages.  
     
     
         48 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank, interposing a material having viscous-flow properties between the blank and the core and placing the blank, core and interposed material within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained that prevents the sheath and blank from displacement relative to each other and working the blank with core within the sheath with interposed material according to said first and second stages.  
     
     
         49 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank, subjecting the blank and core to plastic deformation according to said first and second stage and expanding the blank by pressure-feeding a working fluid into a space between the blank and the core.  
     
     
         50 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank and placing the blank and core within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained that prevents the sheath and blank from displacement relative to each other, working the blank with core within the sheath according to said first and second stage and expanding the blank within the sheath by pressure-feeding a working fluid into a space between the blank and the core.  
     
     
         51 . The method of  claim 38 , wherein said blank is a hollow thin-walled blank comprising placing the blank within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained that prevents the sheath and blank from displacement relative to each other during a process of working.  
     
     
         52 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank and placing the blank and core within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained that prevents the sheath and blank from displacement relative to each other and working the blank by displacing the blank and the core relative to each other.  
     
     
         53 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank and placing the blank and core within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained by a brazed joint that prevents the sheath and blank from displacement relative to each other, working the blank with core within the sheath according to said first and second stage and expanding the blank within the sheath by pressure-feeding a working fluid into a space between the blank and the core.  
     
     
         54 . The method of  claim 38 , wherein said blank is hollow and the method comprises placing a core within the blank and placing the blank and core within a sheath capable of undergoing superplastic deformation, subjecting the sheath to uniaxial tensioning until a blank-to-sheath contact along a blank lateral surface is attained by a brazed joint that prevents the sheath and blank from displacement relative to each other, working the blank with core within the sheath according to said first and second stage and expanding the blank within the sheath by pressure-feeding a working fluid into a space between the blank and the core, wherein an initial thickness Δ of a brazing solder interlayer is such that Δ≦0.005 t, where t is thickness of the blank.  
     
     
         55 . The method of  claim 38 , wherein the blank is a plate interposed between a sheath and a rod, wherein contact there between is provided by prestraining the plate, and displacing the sheath and the rod relative each other in the course of working of the blank.  
     
     
         56 . The method of  claim 38 , wherein the blank is a plate interposed between a conical sheath and a conical rod, wherein contact there between is provided by prestraining the plate during assembly, and displacing the sheath and the rod relative each other in the course of working of the blank.  
     
     
         57 . The method of  claim 38 , wherein the blank is a plate interposed between a conical sheath and a conical rod, wherein contact there between is provided by prestraining the plate during assembly, and displacing the sheath and the rod relative each other in the course of working of the blank comprising applying a uniform deforming force to an end face of the blank over an area having radius r equal to 0.7<r<R, where R is the radius of the blank being worked.  
     
     
         58 . A multiple stage method for plastic working of a blank, comprising: 
 deforming by working the blank by applying a torsional loading to the blank at a first stage in multiple steps at loading conditions selected to effect microstructure transformation; and applying a tensile or compression loading at a second stage subsequent to the torsional loading stage,    wherein a deforming force is imparted to the blank through an inseparable joint with a tool.    
     
     
         59 . The method of  claim 58 , wherein a deforming force is imparted to the blank through an inseparable fusion welded joint.  
     
     
         60 . The method of  claim 58 , wherein a deforming force is imparted to the blank through an inseparable solid-phase welded joint.  
     
     
         61 . The method of  claim 58 , wherein a deforming force is imparted to the blank through an inseparable brazed joint.  
     
     
         62 . The method of  claim 58 , wherein a deforming force is imparted to the blank through an inseparable brazed joint, wherein the joint is formed with a brazing solder having a melting point that exceeds the temperature of working the blank.  
     
     
         63 . The method of  claim 58 , wherein a deforming force is imparted to the blank through an inseparable brazed joint, wherein the joint is formed with a brazing solder having a melting point that exceeds the temperature of working the blank, wherein the joint thickness is (0.005÷0.01)D, where D is the transverse dimension of the joint.  
     
     
         64 . A method for plastic working of blanks, comprising: 
 determining deformation accumulated in working a blank;    determining depth of a layer of the blank being wrought;    determining the plasticity reserve of the blank being wrought;    and further applying a number of deformation steps to the blank according to the determined accumulated deformation, layer depth and plasticity reserve.    
     
     
         65 . An article, comprising: 
 a hollow blank with a hollow core emplaced within the blank and expanded by pressurized fluid contained within the core interior and a sheath encompassing the blank in a blank to sheath contact along a blank lateral surface that prevents the sheath and blank from displacement relative to each other.    
     
     
         66 . The article of  claim 65 , further comprising a viscous flow material between the blank and the core.