Cooking utensil made from aluminum alloy strips produced by continuous thin gauge twin roll casting

Abstract

The invention concerns a method for making aluminium alloy strips containing (by weight) at least 0.15 to 1.5% Fe and/or 0.35 to 1.9% Mn, with Fe+Mn<2.5% and optionally Si<0.8%, Mg<0.2%, Cu<0.2%, Cr<0.2%, Zn<0.2%, and other elements each <0.1% and <0.3 % in all, by continuous casting between two cylinders cooled and shrinked to a thickness ranging between 1 and 5 mm, the force applied to the cylinders during casting, expressed in tonnes per meter of strip width, being less than 300+2000/e, e being the cast strip thickness in mm. The invention also concerns strips in alloy of the same composition, twin-roll cast between 1 and 5 mm thick and having a product R 0.2 (MPa)×A (%) greater than 2500, and preferably than 3000.

1 . Method for producing aluminium alloy strips containing(by weight) at least one of elements Fe (from 0.15 to 1.5%) or Mn (from 0.35 to 1.9%) with: Fe+Mn<2.5%, and optionally containing Si (<0.8%), Mg (<0.2%), Cu (<0.2%), Cr (<0.2%), Zn (<0.2%), other elements <0.1% each and 0.3% in all, by continuous twin-roll casting between cooled shrinked cylinders to a thickness of between 1 and 5 mm, optionally followed by cold rolling, the force applied to the rolls during casting, expressed in t per metre of strip width, being less than 300+2000/e, e being the thickness of the cast strip expressed in mm.  
     
     
         2 . Method for producing aluminium alloy strips containing (by weight) at least one of elements Fe (from 0.15 to 1.5%) or Mn (from 0.35 to 1.9%) with Fe+Mn<2.5%, and optionally Si<0.8%, Mg <0.2%, Cu <0.2%, Cr<0.2%, Zn<0.2%, other elements <0.1% each and 0.3% in all, by continuous twin-roll casting between cooled shrinked cylinders, characterised in that the heat exchange between the metal and the cylinder shells during casting is slowed down such that the temperature of the cylinder shells is higher than 80° C., preferably than 130° C.  
     
     
         3 . Method in accordance with  claim 2 , characterised in that the cylinder shell material has poor thermal conductivity.  
     
     
         4 . Method according to any of  claims 1  to  3 , characterised in that the arc of contact between the metal and the casting rolls is less than 60 mm, preferably less than 56 mm.  
     
     
         5 . Aluminium alloy strip containing (by weight) at least one of elements Fe (from 0.15 to 1.5%) or Mn (from 0.35 to 1.9%) with Fe+Mn<2.5% and optionally containing Si (<0.8%), Mg (<0.2%), Cu (<0.2%) or Zn (<0.2%), other elements <0.1% each and 0.3% in all, continuous cast to a thickness of between 1 and 5 mm, having at the as-cast state a product R 0.2  (in MPa)×A (%) greater than 2500.  
     
     
         6 . Strip according to  claim 5  having a product R 0.2 ×A greater than 3000.  
     
     
         7 . Strip according to either of claims  5  or  6  having a yield strength R 0.2  greater than 80 MPa.  
     
     
         8 . Strip according to  claim 7  having a yield strength R 0.2 >100 MPa.  
     
     
         9 . Strip according to any of claims  5  to 8, having an elongation A>20%.  
     
     
         10 . Strip in Mn-free alloy according to  claim 9  having an elongation A>30%.  
     
     
         11 . Strip according to any of  claims 5  to  10 , having an earing ratio of less than 7.  
     
     
         12 . Strip according to  claim 11 , having an earing ratio of less than 5.  
     
     
         13 . Strip according to any of  claims 5  to  12 , characterized in that the average size of the intermetallic particles containing Fe, Mn and/or Si is no more than 0.4 μm.  
     
     
         14 . Strip according to any of  claims 5  to  13 , characterized in that the size of at least 90% of the intermetallic particles containing Fe, Mn and/or Si is less than 1 μm.  
     
     
         15  Strip in Al-Mn alloy according to any of  claims 5  to  14  with Fe+Mn>1.4% having, after enamelling and/or PTFE anti-adhesive coating treatment, a yield strength of more than 80 MPa, preferably more than 100 MPa.  
     
     
         16 . Strip cold rolled from a strip according to any of claims  5  to 15, characterized in that the k and n coefficients of the work hardening curve R 0.2 =kε n , in which ε=(2/{square root}3)l e  (initial thickness/final thickness) are such that k>150 and n<0.20.  
     
     
         17 . Strip according to  claim 16 , characterized in that n<0.15.  
     
     
         18 . Enamelled and/or PTFE anti-adhesive coated cooking utensil produced from strips according to any of  claims 5  to  17 .  
     
     
         19 . Lacquered or varnished strip according to any of  claims 5  to  17 .