ASTM A540 B21 Grade is a special quality alloy steel used for oil and gas, nuclear and other special heavy engineering applications. The material is quenched, tempered, and fully tested to meet the characteristics of the required class (1 to 5) to suit the application requirement.
LoneStar Fasteners Europe can offer this grade in the standard form or with supplementary testing requirements as detailed in ASTM A540.
ASTM A540 B21: Forms
| LoneStar Manufacture | ||
| Stud Bolts | ✓ | |
| Studding | ✓ | |
| Hexagon Headed Bolting | ✓ | |
| Socket Headed Bolting | ✓ | |
| Double Ended and Waisted Studs | ✓ | |
| Associated OEM Parts | ✓ | |
| Imperial Nuts – Heavy and Normal Series – Including ANSI B18.2.2 | ✓ | |
| Metric Nuts – Regular and High types – Including DIN 934 H=D, ISO | ✓ | |
| Available with locking features | ✓ |
ASTM A540 B21: Sizes and Threads
| LoneStar Manufacture | ||
| Metric Coarse | ✓ | |
| Metric Fine | ✓ | |
| Imperial UNC | ✓ | |
| Imperial 8UN | ✓ | |
| Imperial UNF | ✓ | |
| ACME | ✓ | |
| Metric sizes available | M100 | |
| Imperial sizes available | Up to 6.00″ |
ASTM A540 B21: Chemical Composition
| Carbon | 0.36-0.44 | % |
| Manganese | 0.45-0.70 | % |
| Phosphorus | 0.025 | % Max |
| Sulphur | 0.025 | % Max |
| Silicon | 0.15-0.35 | % |
| Chromium | 0.80-1.15 | % |
| Nickel | – | … |
| Molybdenum | 0.50-0.65 | % |
| Copper | – | … |
| Niobium | – | … |
| Titanium | – | … |
| Vanadium | 0.25-0.35 | % |
| Aluminium | – | … |
| Nitrogen | – | … |
ASTM A540 B21: Mechanical Properties
| Class | Diameter | Tensile Strength Min, | Yield Strength min, 0.2% offset min | Elongation in min % | Reduction of Area min % | Hardness Min | Hardness Max |
| 5 | 2″ and under | 120 | 105 | 15 | 50 | 241 | 285 |
| 5 | Over 2″ to 6″ | 115 | 100 | 15 | 50 | 248 | 302 |
| 5 | Over 6” to 8” | 115 | 100 | 15 | 50 | 255 | 311 |
| 4 | To 3” | 135 | 120 | 13 | 45 | 269 | 331 |
| 4 | Over 3” to 6” | 135 | 120 | 13 | 45 | 277 | 352 |
| 3 | To 3” | 145 | 130 | 12 | 40 | 293 | 352 |
| 3 | Over 3” to 6” | 145 | 130 | 12 | 40 | 302 | 375 |
| 2 | To 4” | 155 | 140 | 11 | 40 | 311 | 401 |
| 1 | To 4” | 165 | 150 | 10 | 35 | 321 | 429 |
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