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Common Materials
ASTM A366
COMMERCIAL QUALITY AND DRAWING QUALITY COLD ROLLED SHEET
Cold rolled commercial quality sheets are produced from rimmed, cast, capped,
or semi-killed steel and are intended for exposed or unexposed parts involving
bending, moderate drawing or forming and welding. They may be bent flat
on themselves in any direction without cracking.
Cold rolled drawing quality sheets are produced from special killed steels,
and are intended for parts involving severe forming or drawing. Sheets
of this quality have a greater degree of ductility and are more consistent
in performance because of higher standards in production, selection, and
processing of the steel. The surface finish is a dull matte texture.
American Specifications:   Commercial quality - ASTM A366;
drawing quality - ASTM A620
British Specifications:   Commercial quality - 1449 4 CR,
1449 4 CS; drawing quality - 1449 1 CR, 2 CR
Applications:   Practical experience is usually sufficient
to determine whether commercial quality or drawing quality is required
for a given part. Where experience is not adequate, the Scribed Square
Test (ASTM A568) can prove helpful. A grid of one inch squares is marked
on the section representing the most severe draw. The squares are measured
for percent increase in area after drawing. Experience has shown that
commercial quality is usually satisfactory if the increase in area is
less than 25%. If more than 25%, drawing quality is recommended.
Size Range:   28 ga - 10 ga
Typical Chemical Analysis:  
| |
Commercial |
Drawing
|
| |
Quality |
Quality
|
| C |
.15 max |
.10 max
|
| Mn |
.60 max |
.50 max
|
| P |
.030 max |
.020 max
|
| S |
.035 max |
.030 max |
|
Typical Mechanical Properties:  
| |
Commercial |
Drawing
|
| |
Quality |
Quality
|
| Tensile strength (ksi) |
38-50 |
36-46
|
| Yield point (ksi) |
25-35 |
23-30
|
| Elongation (% in 2") |
35-42 |
38-43
|
| Rockwell hardness |
RB40-RB60 |
RB38-RB50 |
|
Weldability:   Yes
Size & Weight Table:
Cold Rolled Sheet |
|
| Gauge |
Lb/ft² |
| |
|
| 28 Ga. (.0149") |
0.625 |
| 26 Ga. (.0179") |
0.75 |
| 24 Ga. (.0239") |
1.0 |
| 22 Ga. (.0299") |
1.25 |
| 20 Ga. (.0359") |
1.50 |
| 18 Ga. (.0478") |
2.0 |
| 16 Ga. (.0598") |
2.5 |
| 14 Ga. (.0747") |
3.125 |
| 13 Ga. (.0897") |
3.75 |
| 12 Ga. (.1046") |
4.375 |
| 11 Ga. (.1196") |
5.0 |
| 10 Ga. (.1345") |
5.625 |
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