Overview
A high-strength / low alloy copper bearing grade with a 50,000 minimum yield. The added copper enhances the corrosion resistance through a weathering process. Used primarily in bridges and other construction areas where durability and added strength are needed in an open air atmosphere.
Chemical Requirements
*Elements represented in percentage
Note – Where “-” appears in this table, there is no requirement.
| Element | Composition % | ||
|---|---|---|---|
| Grade A | Grade B | Grade K | |
| CarbonA | 0.19 max | 0.20 max | 0.17 max |
| ManganeseA | 0.80-1.25 | 0.75-1.35 | 0.50-1.20 |
| Phosphorus | 0.04 max | 0.04 max | 0.04 max |
| Sulfur | 0.05 max | 0.05 max | 0.05 max |
| Silicon | 0.30-0.65 | 0.15-0.50 | 0.25-0.50 |
| Nickel | 0.40 max | 0.50 max | 0.40 max |
| Chromium | 0.40-0.65 | 0.40-0.70 | 0.40-0.70 |
| Molybdenum | – | – | 0.10 max |
| Copper | 0.25-0.40 | 0.20-0.40 | 0.30-0.50 |
| Vanadium | 0.02-0.10 | 0.01-0.10 | – |
| Columbium | – | – | 0.005-0.05B |
Tensile Requirements
Note 1 – Where “-” appears in this table, there is no requirement.
| Plates and Bars | |||
|---|---|---|---|
| For Thicknesses 4 in. [100 mm] and Under | For Thicknesses Over 4 in. [100 mm] to 5 in. [125 mm] incl | For Thicknesses Over 5 in. [125 mm] to 8 in. [200 mm] incl | |
| Tensile strength, min, ksi [MPa] | 70 [485] | 67 [460] | 63 [435] |
| Yield point, min, ksi [MPa] | 50 [345] | 46 [315] | 42 [290] |
| Elongation in 8 in. [200 mm], min, % | 18B,C | – | – |
| Elongation in 2 in. [50 mm], min, % | 21B,C | 21B,C | 21B,C |