The term “temper” when applied to tinplate, summarizes a combination of interrelated mechanical properties. There is no single mechanical test that can measure all the factors that contribute to the fabrication characteristics of the material. However, the Rockwell 30T Hardness Test is generally used as a quick test to serve as a guide to the properties of the material. The Rockwell 30T values for tin plate form the basis for classifying tin plate into a system of temper designations.
Temper Characteristics of Tin Mill Products
|Rockwell Hardness Range 30T
|Examples of Usage
|Single Reduced Products
|Soft for drawing.
|Drawn requirements, nozzles, spouts, closures
|Moderate drawing where some stiffness is required.
|Rings and plugs, closures, shallow drawn and specialized can parts
|Shallow drawing, general purpose with fair degree of stiffness to minimize fluting.
|Can ends and bodies, large diameter closures, crown caps
|General purpose where increased stiffness is required.
|Closures, can ends and bodies, drawn and ironed cans
|Increased stiffness to resist buckling.
|Can ends and bodies
|Double Reduced Products
|Relatively hard with limited ductility and highly directional mechanical properties.
|Small diameter round can bodies and ends
|Higher strength than DR 8.
|Larger diameter round can bodies and ends