Black UNC Heavy Full Thread Hex Bolts ASTM A193 Grade B7
Heavy hex bolts black surface UNC full thread ASTM A193 Grade B7
High strength bolts or structural bolts are made to be used with heavy hex nuts to connect structural members. To be considered a structural connection, it has to conform to specific ASTM standards; specifically, ASTM A563 or ASTM A194.
Structural bolts are also categorized by grades. The grading system takes into consideration the bolt’s material, its size range, its proof load, the minimum yield strength, and the minimum tensile strength.
A193 Grade B7: Alloy steel, AISI 4140 / 4142 quenched and tempered.
A193 Grade B8, Class 1: Stainless steel, AISI 304, carbide solution treated.
A193 Grade B8, Class 2: Stainless steel, AISI 304, carbide solution treated, strain hardened.
A193 Grade B8M, Class 1: Stainless steel, AISI 316, carbide solution treated.
A193 Grade B8M, Class 2: Stainless steel, AISI 316, carbide solution treated, strain hardened.
A193 Grade B16: Alloy steel, chromium-molybdenum-vanadium, quenched and tempered.
NOTE: There are other grades of A193. Those listed here are the ones we receive the most requests for.For information on other types, please contact us.
SIZE: 1/4" - 5", M6 -M100. And 600mm Max length.
THREAD: ASME B1.1 , UNC, UNF, CLASS 2A
FINISHED: Plain, Zinc Plated(Clear/Blue/Yellow/Black), Black oxide, Nickel, Dacromet, H.D.G.
| A193 MECHANICAL PROPERTIES | |||||||
| Grade | Size | Tensile, ksi, min | Yield, ksi, min | Elong. % min | RA min | HBW, max | HRC, max |
| B7 | up to 2-1/2" | 125 | 105 | 16 | 50 | 321 | 35 |
| 2-5/8" - 4" | 115 | 95 | 16 | 50 | |||
| 4-1/8" - 7" | 100 | 75 | 18 | 50 | |||
| B8 Class 1 | all | 75 | 30 | 30 | 50 | 223 | 35 |
| B8 Class 2 | up to 3/4" | 125 | 100 | 12 | 35 | 321 | 35 |
| 7/8" - 1" | 115 | 80 | 15 | 35 | |||
| 1-1/8" - 1-1/4" | 105 | 65 | 20 | 35 | |||
| 1-3/8" - 1-1/2" | 100 | 50 | 28 | 45 | |||
| B8M Class 1 | all | 75 | 30 | 30 | 50 | 223 | 96 |
| B8M Class 2 | up to 3/4" | 110 | 95 | 15 | 45 | 321 | 35 |
| 7/8" - 1" | 100 | 80 | 20 | 45 | |||
| 1-1/8" - 1-1/4" | 95 | 65 | 25 | 45 | |||
| 1-3/8" - 1-1/2" | 90 | 50 | 30 | 45 | |||
| B16 | under 2-1/2" | 125 | 105 | 18 | 50 | 321 | 35 |
| over 2-1/2" - 4" | 110 | 95 | 17 | 45 | |||
| over 4" - 8" | 100 | 85 | 16 | 45 | |||
| A193 CHEMICAL PROPERTIES | ||||
| Element | Grade B7 | Grade B8 | Grade B8M | Grade B16 |
| Carbon | 0.37 - 0.49% | 0.08% max | 0.08% max | 0.36 - 0.47% |
| Manganese | 0.65 - 1.1% | 2.0% max | 2.0% max | 0.45 - 0.7% |
| Phosphorus, max | 0.04% | 0.05% | 0.05% | 0.04% |
| Sulfur, max | 0.04% | 0.03% | 0.03% | 0.04% |
| Silicon | 0.15 - 0.35% | 1.0% max | 1.0% max | 0.15 - 0.35% |
| Chromium | 0.75 - 1.2% | 18.0 - 20.0% | 16.0 - 18.0% | 0.8 - 1.15% |
| Nickel | 8.0 - 11.0% | 10.0 - 14.0% | ||
| Molybdenum | 0.15 - 0.25% | 2.0 - 3.0% | 0.5 - 0.65% | |
| Vanadium | 0.25 - 0.35% | |||
| Aluminum, max | 0.02% | |||
| A193 RECOMMENDED HARDWARE | ||
| Grade | Nut | Washer |
| B7 | A194 Grade 2H | F436 |
| B8 Class 1 | A194 Grade 8 | 304 Stainless |
| B8 Class 2 | A194 Grade 8 | 304 Stainless |
| B8M Class 1 | A194 Grade 8M | 316 Stainless |
| B8M Class 2 | A194 Grade 8M | 316 Stainless |
| B16 | A194 Grade 7 | F436 |
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