BETHLEHEM OFFERS A RANGE OF STEEL GRADES, COATING WEIGHTS AND SIZES TO MEET YOUR SPECIFIC REQUIREMENTS.
AVAILABLE STEEL GRADES
Tin mill products are available in various steel grades. Type MR base metal sheet, for general purpose applications, is the most commonly used.
Low in metalloids and residual elements, Type L base metal steel is used for its improved internal corrosion resistance in certain food-product containers. Type D base metal steel is an aluminum killed grade used for severe drawing applications or where stretcher-strains are a hazard. All Bethlehem's Tin Mill Products are produced as aluminum-deoxidized strand cast steel and meet ASTM A623 specification for chemical composition.
COATING WEIGHTS
Tinplate is available in numerous coating weights. The following table, from ASTM A624, shows the more commonly produced coating weights, with the nominal tin weight, per side, and the minimum acceptable average coating weight per side.
Designation
No. |
Nominal Tin Coating
Weight Each Surface,
lb/base box |
Minimum Average
Coating Weight Each
Surface Test Value
lb/base boxA |
10 |
0.05/0.05 |
0.04/0.04 |
20 |
0.10/0.10 |
0.08/0.08 |
25 |
0.125/0.125 |
0.11/0.11 |
35 |
0.175/0.175 |
0.16/0.16 |
50 |
0.25/0.25 |
0.23/0.23 |
75 |
0.375/0.375 |
0.35/0.35 |
100 |
0.50/0.50 |
0.45/0.45 |
D 50/25B |
0.25/0.125 |
0.23/0.11 |
D 75/25 |
0.375/0.125 |
0.35/0.11 |
D 100/25 |
0.50/0.125 |
0.45/0.11 |
D 100/50 |
0.50/0.25 |
0.45/0.23 |
D 135/25 |
0.675/0.125 |
0.62/0.11 |
A. The minimum value shall be not less than 80% of the minimum average tin coating weight.
B. The letter on differentially coated tinplate indicates the coated surface to be marked. For instance, the examples indicate that the heavy-coated side is marked (see 5.1.2. and 5.1.3.).
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