ASTM Fasteners
Manufacturer
India · Mumbai
ASTM Fastener Standards — What Each Covers
ASTM publishes separate fastener standards for different material families and service conditions. Akbar Fasteners manufactures to all major ASTM bolting standards — from A193 pressure vessel stud bolts through A325 structural bolts, A307 anchor bolts, A320 low-temperature service, and beyond. Each card below covers one standard group.
ASTM A193
The primary ASTM standard for high-temperature, high-pressure bolting — stud bolts, bolts, and screws for ASME B16.5 pressure flanges, pressure vessels (ASME VIII), and piping systems (ASME B31.3). Grades: B7 (Cr-Mo alloy steel, ≥862 MPa) · B8 (SS 304) · B8M (SS 316L) · B8T (SS 321) · B8C (SS 347) · B16 (Cr-Mo-V, high-temp) · L7 (alloy steel, low-temp). The most-specified ASTM bolting standard in the refinery and petrochemical industry.
ASTM A194
The matching nut standard for ASTM A193 bolting. Each A193 stud bolt grade has a specified A194 nut: B7 → 2H (carbon steel) or 2HM (NACE); B8M → 8M (SS 316L); B8T → 8T (SS 321). Grade 2H is the standard heavy hex nut for A193 B7 carbon steel stud bolt assemblies. Grade 2HM is the NACE-compliant version for sour service (≤235 HB hardness limit). Specifying the correct A194 grade to match the A193 stud bolt grade is mandatory for compliant documentation.
ASTM A325 / A490
High-strength structural hex bolts for friction-type and bearing-type structural steel connections per AISC and RCSC specifications. A325 (≥830 MPa, medium carbon steel) is the standard structural bolt for steel framing; A490 (≥1040 MPa, alloy steel) for heavier-load structural connections. Now superseded by ASTM F3125 (A325M/A490M metric) for current projects — Akbar Fasteners manufactures to both A325/A490 and F3125 designations. Dia ¾”–1½” (inch) and M20–M36 (metric).
ASTM A307
Low-to-medium strength carbon steel hex bolts for general structural and mechanical applications not requiring the high strength of A325. Grade A (≥413 MPa UTS, ¼”–4″) — standard general-purpose hex bolts, anchor bolts, and equipment mounting bolts. Grade B (≥413 MPa UTS, ¼”–4″, flanged or recessed head) — structural bolting where Grade A is too generic. A307 is the ASTM anchor bolt standard most widely referenced in civil and structural engineering specifications.
ASTM A320
Bolting materials for pressure vessels and process equipment in low-temperature or cryogenic service where Charpy impact testing is required. L7 (Cr-Mo alloy steel, Charpy tested at −100°F/−73°C) · L7M (NACE-compliant L7) · L43 (Ni-Cr-Mo alloy, −150°F/−101°C) · B8M (SS 316L, cryogenic to −423°F/−253°C). The impact test requirement distinguishes A320 from A193 — A320 specifies minimum absorbed energy (Joules) at the test temperature, confirming toughness for low-temperature applications.
ASTM A354
Quenched and tempered alloy steel bolts, studs, and stud bolts of higher strength than A193 B7. Grade BC (≥862 MPa, similar to A193 B7) · Grade BD (≥1034 MPa, higher alloy steel). A354 BD is specified where standard A193 B7 strength (≥862 MPa, continuous thread) is insufficient and the engineer requires higher mechanical properties in the same alloy steel family without moving to A490. Common in bridge construction, heavy machinery, and structural applications with very high bolt loads.
ASTM A193 Stud Bolt → Matching A194 Nut Grade
Specifying the correct A194 nut grade to match the A193 stud bolt grade is a mandatory documentation requirement for ASME B16.5 flange assemblies. Mixed-grade assemblies (e.g. A194 2H nut on A193 B8M stud bolt) are non-compliant. The table below shows the correct pairing for the most common ASTM bolting grades.
| A193 Bolt Grade | Material | Min UTS | Matching A194 Nut | Nut Material | NACE Version |
|---|---|---|---|---|---|
| ASTM A193 — ALLOY STEEL GRADES (CARBON & Cr-Mo) | |||||
| B7 | Cr-Mo Alloy Steel (4140/4142) | ≥862 MPa | 2H | Carbon Steel | 2HM (≤235 HB) |
| B7M | Cr-Mo Alloy Steel (NACE) | ≥724 MPa | 2HM | Carbon Steel NACE | 2HM standard |
| B16 | Cr-Mo-V Alloy (High Temp) | ≥1000 MPa | 4 or 7 | Alloy Steel | — |
| ASTM A193 — STAINLESS STEEL GRADES (B8 SERIES) | |||||
| B8 | SS 304 (S30400) | ≥515 MPa | 8 (Class 1) | SS 304 | — |
| B8M | SS 316L (S31603) | ≥515 MPa | 8M | SS 316L | — |
| B8MN | SS 317L (S31703) | ≥515 MPa | 8MN | SS 317L | — |
| B8T | SS 321 (S32100) | ≥515 MPa | 8T | SS 321 | — |
| B8C | SS 347 (S34700) | ≥515 MPa | 8C | SS 347 | — |
| ASTM A320 — LOW-TEMPERATURE BOLTING | |||||
| L7 | Cr-Mo Alloy Steel | ≥862 MPa | 4 or 7 | Alloy Steel | L7M → 2HM |
| L7M | Cr-Mo Alloy (NACE LT) | ≥724 MPa | 2HM | CS NACE | Standard |
Exotic alloy ASTM grades: Hastelloy B3 stud bolts · Monel K500 · Inconel
ASTM Fastener Types — All Forms Available
Every ASTM fastener form manufactured from ASTM-certified bar stock with full traceability. NABL-accredited mechanical testing on every lot. ASME B16.5 dimensional compliance confirmed.
ASTM Stud Bolts
A193 B7 (alloy steel), B8M (316L SS), B8T (321 SS), B8C (347 SS), B16 (Cr-Mo-V high-temp), L7 (A320 low-temp) stud bolts for ASME B16.5 Class 150–2500 pressure flanges. Fully threaded, equal-end, and unequal-end configurations. M12–M100, lengths to 3,000mm. NABL-accredited tensile and hardness testing on every lot.
ASTM Hex Bolts
A307 Grade A/B general purpose hex bolts, A325 high-strength structural hex bolts (≥830 MPa), A490 high-strength structural (≥1040 MPa), and A354 BD (≥1034 MPa) alloy steel hex bolts. ASTM F3125 metric equivalents (A325M, A490M). Full thread and partial thread. Inch ¼”–4″ and metric M6–M100. AISC-compliant dimensions.
ASTM Hex Nuts
ASTM A194 Grade 2H (B7 standard nut), 2HM (NACE sour service ≤235 HB), 4 and 7 (alloy steel), 8 (304 SS), 8M (316L SS), 8MN (317L SS), 8T (321 SS), 8C (347 SS) heavy hex nuts to ASME B18.2.2. M12–M100. Matched from same certified heat as stud bolts on request. NABL hardness testing confirming NACE hardness limits for 2HM lots.
ASTM Washers
ASTM F436 hardened steel structural washers for A325 and A490 structural bolt assemblies. DIN 125 / ISO 7089 plain flat washers in A193 alloy materials (alloy steel, SS 316L, SS 321) for pressure vessel and process equipment ASTM A193 stud bolt assemblies. ASME B18.21.1 inch-series lock washers available.
ASTM Threaded Rods
A193 B7 and B8M threaded rods for pressure vessel and process equipment structural applications. A36 carbon steel threaded rod for structural and civil engineering applications. Full thread and end-thread. Inch UNC/UNF and metric DIN 976. Lengths to 3,000mm. NABL tensile testing on every lot.
ASTM Assembly Sets
Complete A193 + A194 matched stud bolt assembly sets — stud bolts + heavy hex nuts + washers from the same ASTM-certified heat lot. Single MTC covering stud bolt and nut under one document. NABL hardness certificate for NACE 2HM lots. COC confirming ASTM grade, UNS designation, and dimensional compliance for ASME B16.5.
NACE Sour Service
A193 B7M + A194 2HM matched sets for NACE MR0175 / ISO 15156 sour service (H₂S-containing environments). Hardness certificate per ASTM A370 confirming ≤235 HB (≤22 HRC) for B7M stud bolts and ≤235 HB for 2HM nuts — the NACE hardness limit that prevents sulphide stress cracking. Fully documented NACE-compliant sets for offshore, subsea, and sour gas applications.
Custom ASTM Fasteners
Non-standard ASTM configurations — non-standard diameters, inch thread ASTM A193 B7 in metric equipment, ASTM A354 BD in DIN dimensions, and any cross-standard requirement where an ASTM material grade must be supplied in a non-ASTM dimensional format. Contact sales@akbarfasteners.in with your ASTM grade, DIN/ISO dimensions, and documentation requirements.
When Your Drawing Says ASTM and Your Supplier Uses DIN
EPC projects often mix procurement systems — American process equipment specified to ASTM A193 B7 stud bolts with European structural connections specified to DIN 931 / ISO 4014. Akbar Fasteners manufactures to both standards from the same quality system and can supply mixed documentation sets.
ASTM Fasteners Application Areas
ASTM bolting standards cover every industrial application — from ASME pressure vessel stud bolts through structural steel connections, offshore subsea assemblies, and low-temperature cryogenic service.
Refinery & Petrochemical
B8M SS stud bolt sets
Oil & Gas
2HM matched nut sets
Offshore
subsea structural bolts
Power Generation
A320 L7 boiler bolts
Structural / Civil
A307 anchor bolts
Chemical Processing
ASME VIII vessel bolts
LNG / Cryogenic
Charpy-tested nut sets
Nuclear
nuclear grade bolts
Complete ASTM Documentation Package
ASTM Grade Stated
Tensile · Hardness
NACE 2HM ≤235 HB
Conformance
TÜV · BV · Lloyds
ASTM Certified Exotic Alloy Fasteners
When standard A193 B7 or B8M is insufficient for the corrosion environment — Akbar Fasteners manufactures ASTM-certified exotic alloy fasteners across the complete exotic alloy range. Every exotic alloy order carries the same ASTM material standard certification as standard grades.
Hastelloy C276
View C276 →Hastelloy B3
View B3 →Monel K500
View K500 →Inconel 625 / 718
View Inconel →Incoloy 825 / 925
View Incoloy →SS 904L
View 904L →SS 321 — ASTM B8T
View SS 321 →SS 310S — High Temp
View SS 310S →Need ASTM
Certified Fasteners?
ASTM standard · grade · form · size · NACE requirement · documentation package. Akbar Fasteners Pvt. Ltd. responds within 24 hours with pricing and full documentation list.
Export: +91 8696 32 4646 · Support: +91 800 9315 333 · export@akbarfasteners.in