ASME/ANSI B18.2.1 Hex Flange Bolts
ASME/ANSI B18.2.1 Hex Flange Bolts feature an integral flange beneath the hexagonal head, providing a larger bearing surface than a conventional hex head bolt. The flange helps distribute clamping force over a wider area of the joint and can reduce localized pressure on the connected material. Because the flange is formed as part of the bolt, no separate washer is required where the joint design permits its use.
The hexagonal head provides standard wrench or socket access, while the integrated flange remains fixed to the bolt throughout installation. This one-piece configuration can simplify assembly and reduce the number of loose components required in a fastening joint. These bolts are manufactured in inch-series sizes and can be supplied in carbon steel, alloy steel, or stainless steel, with the applicable material and mechanical requirements selected according to the intended application.
Specification:
| Item | Specification |
|---|---|
| Product Standard | ASME/ANSI B 18.2.1 |
| Product Type | Hex Flange Bolt |
| Head Style | Hexagon Head with Integral Flange |
| Thread Standard | ASME B1.1 Unified Inch Screw Threads |
| Thread Pitch | UNC/UNF |
| Thread Size | 1/4"-3/4" |
| Mechanical Proerty | Steel: SAE J 429 Stainless Steel: F593 |
| Material | Carbon Steel, Alloy Steel, Stainless Steel |
| Surface Treatment | Zinc Plated,Black Oxidation,Bright Finish,Passivation |
| Test Standard | ASTM F606/F606M |
- RELATED BOLT LISTS:
- FLANGE BOLTS
- DIN 6921 FLANGE BOLTS
- JIS 1189 FLANGE BOLTS
- HEX BOLTS
- DIN933 HEX BOLTS
- ISO 4017 HEX BOLTS
- ISO 4014 HEX BOLTS
- ASME B 18.2.1 HEX BOLTS
- HEAVY HEX BOLTS
- DIN 6914 STRUCTURAL BOLTS
- AS 1252 STRUCTURAL BOLTS
- ASME B 18.2.1 HEAVY HEX BOLTS
- ASME B 18.2.6 HEAVY HEX BOLTS
- JIS 1186 BOLTS
- EN 14399-3 BOLTS
- EN 14399-4 BOLTS
Dimension Chart:
| Thread Diameter | 1/4 | 5/16 | 3/8 | 7/16 | 1/2 | 9/16 | 5/8 | 3/4 |
| P | 20|28|32 | 18|24|32 | 16|24|32 | 14|20|28 | 13|20|28 | 12|18|24 | 11|18|24 | 10|16|20 |
| ds max | 0.25 | 0.3125 | 0.375 | 0.4375 | 0.5 | 0.5625 | 0.625 | 0.75 |
| ds min | 0.245 | 0.3065 | 0.369 | 0.4305 | 0.493 | 0.5545 | 0.617 | 0.741 |
| s max | 0.375 | 0.5 | 0.5625 | 0.625 | 0.75 | 0.8125 | 0.9375 | 1.125 |
| s min | 0.367 | 0.489 | 0.551 | 0.612 | 0.736 | 0.798 | 0.922 | 1.1 |
| e max | 0.433 | 0.577 | 0.65 | 0.722 | 0.866 | 0.938 | 1.083 | 1.299 |
| e min | 0.409 | 0.548 | 0.618 | 0.685 | 0.825 | 0.895 | 1.034 | 1.234 |
| dc max | 0.56 | 0.68 | 0.81 | 0.93 | 1.07 | 1.19 | 1.33 | 1.59 |
| k max | 0.28 | 0.32 | 0.39 | 0.46 | 0.51 | 0.57 | 0.62 | 0.73 |
Mechanical Property:
Stainless Steel ASME B18.2.1 Hex Flange Bolts-F593
For stainless steel flange bolts to ASME B18.2.1, ASTM F593 provides the material and mechanical property requirements. Common options include F593C and F593D for 304/304L stainless steel flange bolts, and F593G for 316/316L stainless steel flange bolts.
| Mechanical Property Marking | Diameter,in | Full-Size Tests | Machine Specimen Test | ||||
| Tensile Strength (ksi) | Yield Strength (ksi) | Rockwell Hardness | Tensile Strength (ksi) | Yield Strength (ksi) | Elongation in 4D,% | ||
| F593C | 1/4"-5/8" | 100-150 | 65 | B95-C32 | 95 | 60 | 20 |
| F593D | 3/4"-1"-1/2" | 85-140 | 45 | B80-C32 | 80 | 40 | 25 |
| F593C | 1-1/8"-1-1/4" | 100-140 | 60 | B95-C30 | 95 | 55 | 20 |
| F593D | 1-1/8"-1-1/2" | 95-130 | 45 | B90-C28 | 90 | 40 | 28 |
| F593G | 1/4"-5/8" | 100-150 | 65 | B95-C32 | 95 | 60 | 20 |
| F593H | 3/4"-1"-1/2" | 85-140 | 45 | B80-C32 | 80 | 40 | 25 |
| F593G | 1-1/8"-1-1/4" | 100-140 | 60 | B95-C30 | 95 | 55 | 20 |
| F593H | 1-1/8"-1-1/2" | 95-130 | 45 | B90-C28 | 90 | 40 | 28 |
Carbon Steel & Alloy Steel Bolts-SAE J 429
| GRADE | Nominal Size, inches | Full Size Proofload, psi | Yield Strength, min, psi | Tensile Strength, min, psi | Elong, min, % | RA, min, % | Core Hardness, Rockwell | Tempering Temperature, min |
|---|---|---|---|---|---|---|---|---|
| 2 | 1/4 thru 3/4 | 55000 | 57000 | 74000 | 18 | 35 | B80-B100 | N/A |
| Over 3/4 thru 1-1/2 | 33,000 | 36,000 | 60,000 | 18 | 35 | B70 to B100 | ||
| 5 | 1/4 thru 1 | 85,000 | 92,000 | 120,000 | 14 | 35 | C25 to C34 | 800F |
| Over 1 thru 1-1/2 | 74,000 | 81,000 | 105,000 | 14 | 35 | C19 to C30 | ||
| 8 | 1/4 thru 1-1/2 | 120,000 | 130,000 | 150,000 | 12 | 35 | C33 to C39 | 800F |
| Grade 2 requirements for sizes 1/4" thru 3/4" apply only to bolts 6" and shorter, and to studs of all lengths. For bolts longer than 6", Grade 1 requirements shall apply. | ||||||||
Application of ASME/ANSI B18.2.1 Hex Flange Bolts:
Pumps, Compressors and Power Equipment
Used for pump housings, compressor assemblies, generator mounts, motor bases, equipment covers, and other serviceable mechanical components where inch-series fastening is specified.
Agricultural and Heavy Equipment
Suitable for tractors, agricultural machinery, loaders, excavators, and other heavy-duty equipment using UNC or UNF threaded connections. The integral flange provides a larger seating surface beneath the bolt head.
Material Handling and Industrial Machinery
Used in conveyors, lifting equipment, industrial carts, machine assemblies, and equipment frames where standardized inch-series bolts are required for component fastening.