Metal container suitable to accommodate a heating or cooling component method and for manufacturing it

Abstract

A method of producing a metal container from a low carbon steel strip or sheet coated on at least one of its surfaces with a coherent laminated coating of a thermoplastic polymer material includes one or more redrawing stages which reduce the thickness of the side walls by a drawing/stretching operation, and a partial reverse redrawing stage to produce an initial internal chamber whose depth is produced by a reduction of its height. The initial internal chamber is then redrawn to produce two chambers of differing diameter and depth, the diameter of the initial chamber being decreased by the redraw operation and inserting by base reforming the final chamber with a new internal diameter and depth produced by a reduction in the container height.

1 . Method of producing a metal container from a low carbon steel strip or sheet coated on at least one of its surfaces with a coherent laminated coating of a thermoplastics polymer material in which a blank produced from the coated steel strip of sheet to a drawing operation to produce a cup, the method being comprised of the following steps: 
 (i) subjecting the cup to at least one drawing and stretching operation to reduce the thickness of the cup wall and to increase the cup height without ironing of the wall surface;    (ii) subjecting the stretched cup to at least on partial reverse redrawing operation to produce within the stretched cup a first internal chamber whose depth is produced by a reduction of its height without any reduction in wall thickness;    (iii) subjecting the first internal chamber to a reverse redrawing operation to produce a second internal chamber whose diameter and depth differs from those of the first internal chamber; and    (iv) subjecting the cup base to a reforming operation to produce a third internal chamber whose diameter and depth differ from those of the first and second chamber and whose depth is produced by a reduction in the cup height.    
   
   
       2 . Method according to  claim 1  wherein the thermoplastic polymer has good formability and comprises an internal coating which prevents corrosion of the container by its contents and an external coating which prevents corrosion of the container by its heating/cooling solution, the laminate coating being applied to the metal surface by means of direct extrusion or lamination.  
   
   
       3 . Metal container produced by a method as claimed in  claim 1  having a combination of internal chambers of differing depths and diameters.  
   
   
       4 . Metal container as claimed in  claim 3  produced from a double reduced high strength high ductility low carbon steel having a proof strength in the range 490 to 720 N/mm.  
   
   
       5 . Metal container as claimed in  claim 3  wherein the maximum carbon level for the steel is 0.050% by weight.  
   
   
       6 . Metal container as claimed in  claim 4  wherein the steel comprises by weight %: C 0.01-0.10; S 0.02 max.; P 0.015 max.; Mn 0.15-0.30; Ni 0.04 max.; Cu 0.06 max.; Sn 0.02 max.; As 0.01 max.; Mo 0.01 max.; Cr 0.06 max.; Al 0.02-0.09 and N 0.003 max.  
   
   
       7 . Metal container as claimed in  claim 4  wherein the steel is reduced by hot or cold rolling to a gauge of between 0.12′ mm and 0.3 mm.