Stainless Steel
Fasteners
Manufacturer India
India’s Stainless Steel Fastener Manufacturer — ISO 9001:2015
Akbar Fasteners Pvt. Ltd. manufactures stainless steel fasteners across the complete austenitic, ferritic, duplex, and super duplex grade range from our ISO 9001:2015 certified Mumbai facility. The stainless steel fastener range is the foundation of our catalogue — complementing our exotic alloy range of Hastelloy, Monel, and Inconel fasteners — for applications where stainless steel is the correct and sufficient specification.
The most important selection principle: not every corrosive application requires exotic alloy. SS 316L is the correct and cost-effective specification for the vast majority of chemical, pharmaceutical, marine deck, and food processing fastener applications. The step-up from 316L to Duplex 2205 is taken when chloride SCC risk is elevated. The step up from 316L to 904L is taken when higher Mo is required. The step from any stainless to Hastelloy or Monel is taken only when stainless fails in the specific service — and that failure should be confirmed or clearly predictable, not assumed.
All stainless steel fasteners from Akbar Fasteners are manufactured from certified ASTM or BS grade bar stock, PMI-verified before machining, and dispatched with MTC, COC, and NABL test reports. Same documentation quality as our Hastelloy range.
10+ Grades — One Source
304, 304L, 316, 316L, 316Ti, 310S, 317L, 321, 347, 904L, Duplex 2205, Super Duplex 2507. All from certified ASTM/EN grade bar stock with full heat traceability.
100% PMI Before Machining
All SS bar stock PMI-verified by XRF before machining to prevent grade substitution. Critical for 316L vs 304 and for high-molybdenum grades (904L, 2507) where visual inspection cannot confirm composition.
ASTM A193/A194 Stainless Stud Bolts
Stainless steel stud bolts to ASTM A193 B8 (304) and B8M (316) with matching ASTM A194 8 and 8M nuts — the standard ASME B16.5 stainless stud bolt specification for chemical and pharmaceutical flanges at ambient temperature.
When SS Is Not Enough — We Upgrade
When your application exceeds stainless steel’s limits, our Hastelloy, Monel, Inconel, and Nickel alloy ranges are available from the same certified Mumbai facility with the same quality system.
Stainless Steel Fastener Grade Profiles
Ten stainless steel grades available from stock and order. Select based on corrosion environment, temperature, and PRE requirement. All manufactured from certified ASTM / EN grade bar stock with NABL-accredited test reports.
SS 304 / 304L
SS 316 / 316L
SS 310S
SS 317L
SS 321 / 347
SS 904L
Duplex 2205
Super Duplex 2507
SS 316Ti
SS Fastener Types & Standards
All product forms available in all SS grades. ASTM A193/A194 stainless stud bolt sets and ISO 3506 hex bolt assemblies as standard. Custom lengths, fine pitch, and non-standard dimensions on request.
SS Stud Bolts
ASTM A193 B8 (304) and B8M (316/316L) fully threaded stud bolts with matching ASTM A194 8 and 8M heavy hex nuts — the standard stainless stud bolt assembly for ASME B16.5 chemical, pharmaceutical, and food processing pressure flanges. Class 150–600 typical. M12–M100.
SS Hex Bolts
Full thread (DIN 933 / ISO 4017) and partial thread (DIN 931 / ISO 4014) hex bolts in all SS grades. A2-70 (304) and A4-80 (316L) high-tensile stainless hex bolts to ISO 3506-1 for corrosion-resistant structural connections, chemical plant equipment covers, and marine deck bolting. M6–M100.
SS Hex Nuts
Standard hex (DIN 934), heavy hex (ASME B18.2.2), and coupling nuts in all SS grades. ASTM A194 8M (316L) matched nuts for ASTM A193 B8M stud bolts — same certified heat for single MTC. A4 nuts to ISO 3506-2 for ISO 4014/4017 hex bolt assemblies.
SS Washers
Plain flat (DIN 125 / ISO 7089), spring helical (DIN 127), and large OD (DIN 9021) in all SS grades. 304, 316L, 904L, and Duplex 2205 washers — plain and passivated. M4–M100. Same grade as matching bolt and nut for complete assembly in seawater, marine, and chemical service.
SS Threaded Rods
Full thread and end-thread threaded rods. 304, 316L, 316Ti, 904L, and Duplex 2205. M6–M100, lengths to 3,000mm. Chemical plant hanger systems, pharma equipment structural rods, seawater system tie-rods, and food processing equipment support rods.
SS Socket Cap Screws
A2 (304) and A4 (316L) hex socket cap screws to ISO 4762 / DIN 912 for food processing equipment, pharmaceutical plant, marine instrument connections, and all confined-access applications where hex head clearance is unavailable. M3–M36 standard stock. Passivated finish.
Countersunk / Allen Screws
A2 and A4 countersunk (DIN 7991), button head (ISO 7380), and set screws in stainless steel for equipment finishing, food-grade surfaces, hygiene-critical applications, and flush-fastening requirements in stainless steel equipment. M3–M20.
Custom SS Fasteners
Inch UNC/UNF thread (ASTM A193 B8/B8M), non-standard diameters, flanged hex (DIN 6921), coupling nuts (DIN 6334), eye bolts, anchor bolts, and drawing-specific configurations in any SS grade. Contact sales@akbarfasteners.in with specification.
SS Grade, Finish & Standard Reference
Standard finishes and DIN/ASTM/ISO designations for the most common stainless steel fastener grades. All grades available in plain, passivated, and electro-polished finishes unless noted.
| Grade | UNS / EN | ASTM Stud Bolt | ISO 3506 | PRE (approx.) | Standard Finish | Best Application |
|---|---|---|---|---|---|---|
| AUSTENITIC STAINLESS STEEL FASTENERS — MOST COMMON GRADES | ||||||
| SS 304 / 304L | S30400 / S30403 | A193 B8 | A2-70 | ~18 | Plain · Passivated | Food · Pharma · General |
| SS 316 / 316L | S31600 / S31603 | A193 B8M | A4-70 / A4-80 | ~24 | Plain · Passivated | Chemical · Marine · ASME |
| SS 316Ti | S31635 / 1.4571 | — | A4 (approx.) | ~24 | Plain · Passivated | DIN / European chem. plant |
| SS 317L | S31703 | A193 | — | ~28 | Plain · Passivated | Higher-Mo chemical |
| SS 321 | S32100 | A193 B8T | — | ~18 | Plain | Weld HAZ · Heat exchangers |
| SS 347 | S34700 | A193 B8C | — | ~18 | Plain | Nuclear · Nb-stabilised |
| SS 310S | S31008 | — | — | ~20 | Plain | High temp to 1100°C |
| HIGH-ALLOY & DUPLEX STAINLESS STEEL — ELEVATED CORROSION RESISTANCE | ||||||
| SS 904L | N08904 | — | — | ~36 | Plain · Passivated · EP | H₂SO₄ dilute · H₃PO₄ |
| Duplex 2205 | S31803 / S32205 | — | — | ~35 | Plain · Passivated | Offshore · High-Cl seawater |
| Super Duplex 2507 | S32750 | — | — | ~43 | Plain · Passivated | FPSO · Aggressive seawater |
EP = electro-polished. For alloys beyond SS (Hastelloy, Monel, Inconel) when stainless fails: Hastelloy Range
SS Fastener Applications
Stainless steel fasteners cover the majority of industrial, chemical, pharmaceutical, marine, and food processing bolted connection requirements where exotic alloys are not necessary.
Pharmaceutical
GMP equipment fasteners
Chemical Processing
904L high-chloride flanges
Offshore & Marine
Super Duplex 2507 FPSO
Food Processing
AISI 316L sanitary hex bolts
Water Treatment
Duplex pump body bolts
Desalination
seawater circuit flanges
Power Generation
321 heat exchanger bolts
Petrochemical
347 weld zone bolts
SS Fastener Standards Coverage
When stainless steel exceeds its service limit, our exotic alloy range covers the next step — same Mumbai facility, same quality system.
When Stainless Steel Is Not Enough — Upgrade to Exotic Alloy
Stainless steel fasteners fail in concentrated H₂SO₄, reducing HCl, hot concentrated caustic (NaOH), and in seawater with oxidising agents or elevated temperature. When your application exceeds the limits of even Super Duplex 2507 (PRE≈43), the correct next step is Hastelloy C276 (PRE≈66), Hastelloy C22 (PRE≈73), or Monel K500 for seawater. Akbar Fasteners Pvt. Ltd. manufactures the complete exotic alloy range from the same ISO 9001:2015 certified Mumbai facility — one vendor, one quality system, grade selection guidance on request.
Complete Documentation Package
Grade & Heat Traceable
Conformance
100% Lots Verified
Tensile · Hardness
TÜV · BV · Lloyds
Need SS Fasteners
or Exotic Alloy Upgrade?
Grade · standard · size · finish · quantity · documentation. Akbar Fasteners Pvt. Ltd. responds within 24 hours with pricing, lead time, and MTC list.
Export: +91 8696 32 4646 · Support: +91 800 9315 333 · export@akbarfasteners.in