High hardness moulding plate and method for producing said plate

Abstract

Moulding plate of an aluminium wrought alloy including, in weight percent: Si 1.4-2.1, Mn 0.8-1.2, Cu 0.45-0.9, Mg 0.7-1.2, Ti <0.15, Zn <0.4, Fe <0.7, one or more of Zr, Cr, V each <0.25, incidental elements and impurities, each <0.05, total <0.25, the balance aluminium, and having a thickness of more than 0.6 mm and in T6 temper condition having a hardness of more than 105 HB. A method of making the plate is also disclosed.

1 . Moulding plate of an aluminium wrought alloy comprising, in weight percent: 
 Si 1.4-2.1    Mn 0.8-1.2    Cu 0.45-0.9    Mg 0.7-1.2    Ti <0.15    Zn <0.4    Fe <0.7    one or more of Zr, Cr, V each <0.25    incidental elements and impurities, each <0.05, total <0.25,    the balance aluminium, and    having a thickness of more than 0.6 mm and in T6 temper condition having a hardness of more than 105 HB.    
   
   
       2 . Moulding plate according to  claim 1 , wherein Si is in the range of 1.53-2.0%.  
   
   
       3 . Moulding plate according to  claim 1 , wherein Si is in the range of 1.55-1.9%.  
   
   
       4 . Moulding plate according to  claim 1 , wherein Mn is in the range of 0.85-1.10%.  
   
   
       5 . Moulding plate according to  claim 1 , wherein Cu is in the range of 0.5-0.7%.  
   
   
       6 . Moulding plate according to  claim 1 , wherein Mg is in the range of 0.9-1.1%.  
   
   
       7 . Moulding plate according to  claim 1 , wherein Zn is below 0.3%.  
   
   
       8 . Moulding plate according to  claim 1 , wherein Zn is in the range of 0.17-0.3%.  
   
   
       9 . Moulding plate according to  claim 1 , wherein the moulding plate has a machinability rating of “B” or better.  
   
   
       10 . Moulding plate according to  claim 1 , wherein the moulding plate has a final thickness in the range of 5 to 300 mm.  
   
   
       11 . Moulding plate according to  claim 1 , wherein the moulding plate has a final thickness in the range of 5 to 260 mm.  
   
   
       12 . Moulding plate according to  claim 1 , wherein the moulding plate has been rolled to the final thickness by hot rolling only.  
   
   
       13 . Moulding plate according to  claim 1 , having a hardness of more than 115 HB.  
   
   
       14 . Moulding plate according to  claim 1 , having a hardness of more than 120 HB.  
   
   
       15 . Method of manufacturing a moulding plate comprising the sequential steps of: 
 casting a composition comprising (in weight percent): 
 Si 1.4-2.1  
 Mn 0.8-1.2  
 Cu 0.45-0.9  
 Mg 0.7-1.2  
 Ti <0.15  
 Zn <0.4  
 Fe <0.7  
 one or more of Zr, Cr, V each <0.25  
 incidental elements and impurities, each <0.05, total <0.25,  
 balance aluminium,  
   homogenising and preheating the cast composition,    working the homogenized and preheated cast composition to form said plate to a final thickness,    subjecting said plate to heat treatment comprising solution heat treating followed by rapid cooling,    ageing said plate,    wherein the cooling rate during said rapid cooling is chosen to obtain a hardness of the moulding plate of at least 105 HB.