Warm forming of metal alloys at high and stretch rates

Abstract

Process for production of metallic components by warm forming of blanks of alloys with superplastic micro-structure, wherein the deforming pressure in the deforming tool is kept at least 20% below the deformation pressure necessary for forging of the respective alloy without superplastic micro-structure, and the expansion rate ({acute over (ε)}) of the warm forming is adjusted to a value above 0.1/s, or wherein the expansion of the blank during The warm forming is maintained below 50% of the expansion value achievable by a superplastic deforming and the expansion rate ({acute over (ε)}) which is at least the 100 fold of that for superplastic deformation, as well as drive shafts, gears, pinions or profile pans obtainable thereby.

1 . A process for production of metallic components by warm forming of blanks of alloys with superplastic microstructure, comprising: 
 deforming said blank with a deformation tool, wherein the deformation pressure in the deformation tool is kept at least 20% below the deformation pressure necessary for forging of the respective alloy without superplastic micro-structure, and wherein the expansion rate ({acute over (ε)}) of the warm deforming is adjusted to values above 0.1/s.    
     
     
         2 . A process for production of metallic components by warm forming of blanks of alloys with superplastic micro-structure, comprising 
 expanding the blank during warm forming, maintaining expansion below 50% of the expansion value achievable by superplastic deformation, and with an expansion rate ({acute over (ε)}) which is at least the 100 fold of that for superplastic deformation.    
     
     
         3 . A process according to  claim 1 , wherein the warm forming is carried out a temperature range, which corresponds to the process window of a superplastic deformation.  
     
     
         4 . A process according to  claim 1 , wherein the warm forming occurs within the forging temperature of the alloy.  
     
     
         5 . A process according to  claim 1 , wherein alloys are employed which during existence of a superplastic micro-structure exhibit an expansion rate sensitivity (m) above 0.4.  
     
     
         6 . A process according to  claim 1 , wherein an alloy is selected, of which the maximal superplastic expansion lies above 500%.  
     
     
         7 . A process according to  claim 1 , wherein the deformation leads to expansion of the blank in the range of 100 to 400 percent.  
     
     
         8 . A process according to  claim 1 , wherein the warm forming is adjusted to a process time below 10 s.  
     
     
         9 . A process according to  claim 1 , wherein as alloy UHC-Steel is employed, which essentially has the following composition (in wt. %): 
 C: 0.9-2.2; Al: 1.5-10; Cr: 0.5-7; Mn 1-10; rest Fe and impurities    C: 0.9-2.2; Al: 1.5-10; Cr: 1-16; Mn 0-2.2; rest Fe and impurities    C: 0.9-2.2; Al: 1.5-10; Cr: 0.25-5; 0.5-5 Mo; Mn: 0-2; rest Fe and impurities    C: 0.9-2.2; Al: 1.5-3; Cr: 1-7; Si: 0.5-5; Mn 0-2.2; rest Fe and impurities    C: 0.9-2.2; Al: 1.5-10; Cr 1-7; Ni: 0.25-5; Mn 0-2.2; rest Fe and impurities    0.8 to 2.5 C; 0.1 to 0.85 Sn; 3.5 to 15 Al; 0.5 to 4 Cr; 0.01 to 4 Si; up to 4 Ni, Mn, Mo, Nb, Ta, V, and/or W, and up to 3 of Ti, Be and/or Ga; rest Fe and impurities.    
     
     
         10 . A process according to  claim 9 , wherein the warm forming is carried out in the presence of air.  
     
     
         11 . A process according to  claim 7 , wherein the process heat is employed for a controlled cooling of the component.  
     
     
         12 . A process according to  claim 7 , wherein annealing occurs during cooling.  
     
     
         13 . A process according to  claim 1 , wherein Al-alloys are employed, which essentially exhibit the following composition (in wt. %): 
 70-79% Zn, rest Al;    6-8% Al, 4-6% V, rest Ti;    4-6% Al, 2-3% Fe, rest Ti.    
     
     
         14 . A process according to  claim 1 , wherein as alloy, a steel with the following composition is selected: 
 C<0.5%, Si<1,2% m Mn<2.8%, Cr: 15-23%, Ni: 3-9%, Mo: 1-1.9%, N: 0.09-0.25%, rest Fe and impurities.    
     
     
         15 . A process according to  claim 1 , wherein the warm forming is carried out as extrusion, transverse rolling, bore pressing, round working, mesh rolling, punch forming go internal high pressure forming or combinations thereof.  
     
     
         16 . A process according to  claim 1 , wherein multi-warm forming steps are carried up sequentially on the same part.  
     
     
         17 . Drive shafts, gears, pinions or profile parts obtained by a process for production of metallic components by warm forming of blanks of alloys with superplastic microstructure, comprising: 
 deforming said blank with a deformation tool, wherein the deformation pressure in the deformation tool is kept at least 20% below the deformation pressure necessary for forging of the respective alloy without superplastic micro-structure, and wherein the expansion rate ({acute over (ε)}) of the warm deforming is adjusted to values above 0.1/s.    
     
     
         18 . Drive shafts, gears, pinion or profile parts according to  claim 17 , wherein they are formed of UHC-Steels with a superplastic micro-structure.  
     
     
         19 . (canceled)