SS 316 / 316L FastenersASTM A193 B8M · Manufacturer, stockist & exporter, India
Also sold as AISI 316L · UNS S31603 · W.Nr 1.4404 · Marine-grade stainless
SS 316 / 316L fasteners — stud bolts, hex bolts, nuts and washers: bolts, studs and cap screws to ASTM A193 B8M and nuts to ASTM A194 8M where specified; washers, threaded rod and other types to the purchase specification. Dimensions to ASME B18 where applicable, or your drawing. It is a molybdenum-bearing austenitic stainless steel, chosen for chloride-bearing process fluids, marine air and pharmaceutical service. Kanak Steel & Engineering Co. supplies it with EN 10204 3.1 mill certificates from Mumbai to buyers across India, the Gulf, South-East Asia, South America, Europe, the UK and the USA.
- Stock & mill supply
- EN 10204 3.1 / 3.2
- PMI on request
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is SS 316 / 316L Fasteners?
SS 316 / 316L fasteners is a molybdenum-bearing austenitic stainless steel supplied as fasteners (UNS S31603) — bolts, studs and cap screws to ASTM A193 B8M and nuts to ASTM A194 8M where specified; washers, threaded rod and other types to the purchase specification. Buyers specify it for chloride-bearing process fluids, marine air and pharmaceutical service. It is also sold as AISI 316L, UNS S31603, W.Nr 1.4404.
- What it is
- Molybdenum-bearing austenitic stainless steel
- Material
- ASTM A193 B8M · A194 8M
- Dimensions
- ASME B18.2.1 · B18.2.2 · B18.31.2
- Threads
- UNC · UN-8 · metric
- Sizes
- M10 – M64 · ½" – 4"
- Best at
- Chloride-bearing process fluids, marine air and pharmaceutical service
SS 316 / 316L Fasteners Specification & Sizes
| Material | ASTM A193 B8M · A194 8M |
|---|---|
| Scope by type | bolts, studs and cap screws to ASTM A193 B8M and nuts to ASTM A194 8M where specified; washers, threaded rod and other types to the purchase specification |
| Dimensional standards | ASME B18.2.1 (bolts) · B18.2.2 (nuts) · B18.31.2 (studs) · DIN 931 / 933 / 934 (legacy DIN) |
| Types | Stud bolt · Hex bolt · Heavy hex nut · Hex nut · Washer · Threaded rod · U-bolt · Eye bolt · Anchor bolt · Foundation bolt · Socket head cap screw · Machine screw |
| Threads | UNC, UN-8 and metric coarse |
| Coating | Plain · PTFE on request |
| Documents | EN 10204 3.1 |
SS 316 / 316L Stud Bolts: Grade & Nut Pairing
Pressure bolting in this material is ASTM A193 B8M studs with ASTM A194 8M heavy hex nuts. A193 B8-series bolting comes in Class 1 (carbide solution treated) and Class 2 (strain hardened, higher strength) — state the class.
Torque (T = K × F × d), stud length and coatings are covered in the fasteners guide.
| Galling | Stainless and nickel-alloy threads gall — always use anti-seize, and avoid high-speed tightening |
|---|---|
| Coatings | Usually supplied plain; PTFE coating on request to ease tightening |
| Marking | Grade symbol and maker's mark on each stud end and nut, as the standard requires |
| Certificates | EN 10204 3.1 for the bar heat; mechanical test reports on the finished bolts on request |
SS 316 / 316L Fasteners Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Chromium | As specified |
| Nickel | As specified |
| Molybdenum | As specified |
| Carbon | As specified |
| Manganese | As specified |
| Silicon | As specified |
| Nitrogen | As specified |
| Phosphorus | As specified |
| Sulphur | As specified |
| Iron | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM A240 for UNS S31603.
SS 316 / 316L Fasteners Mechanical Properties
Under technical review for TDS.
| Property | Current requirement |
|---|---|
| Tensile strength | As specified |
| Yield strength 0.2% | As specified |
| Elongation | As specified |
| Hardness | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification and condition to be verified: ASTM A240 for UNS S31603 — Annealed plate & sheet (316L).
Density & Physical Properties
| Property | Value |
|---|---|
| Density | 8 g/cm³ |
| Melting range | 1375 – 1400 °C |
| Magnetic | Non-magnetic annealed |
| PREN (approx.) | ≈ 24 |
SS 316 / 316L Equivalent Grades
Six-digit Harmonized System heading (iron and steel, chapter 72–73). Your country adds its own digits — confirm with your customs broker. All HS codes.
How to Verify SS 316 / 316L Fasteners with PMI
Positive material identification with a handheld XRF gun confirms the alloy on the piece itself, in seconds, before it is cut or welded. SS 316 / 316L is most often mixed up with SS 304 — the table shows which elements tell them apart.
Handheld XRF does not measure carbon or nitrogen, so it cannot tell 316 from 316L: the low carbon is confirmed by the mill certificate or optical emission (OES) testing. PMI can be arranged on request — state it on your enquiry.
Under technical review for TDS.
| Element | SS 316 / 316L | SS 304 |
|---|---|---|
| Nickel | As specified | As specified |
| Chromium | As specified | As specified |
| Molybdenum | As specified | — |
| Iron | As specified | As specified |
| Manganese | As specified | As specified |
SS 316 / 316L fasteners by type
SS 316 / 316L Fasteners Applications
SS 316 / 316L is specified when the cheaper grade will not survive the service but a higher alloy would be more than the job needs. These are the jobs our buyers use it for.
SS 316 / 316L Fasteners vs 304, 904L and 2205
| Grade | Fasteners standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| SS 304 | ASTM A193 B8 · A194 8 | ≈ 18 | General corrosion resistance, food, water and architectural work |
| SS 316 / 316L | ASTM A193 B8M · A194 8M | ≈ 24 | Chloride-bearing process fluids, marine air and pharmaceutical service |
| SS 904L | May be machined from ASTM A479 bar (UNS N08904), where applicable; finished fastener requirements are to the purchase specification or project drawing | ≈ 35 | Dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water |
| Duplex 2205 | ASTM A1082 (S32205) where specified for applicable duplex bolts, studs, cap screws and nuts; for other types, material may be supplied to ASTM A276 / A479 bar where applicable, subject to the purchase specification | ≈ 35 | Strength with chloride resistance at a stainless-steel budget |
PREN = Cr + 3.3 Mo + 16 N, from mid-range chemistry. A screening guide, not a substitute for corrosion data on your medium.
SS 316 / 316L Corrosion Resistance — Element by Element
Each alloying addition has a job. Knowing which one protects against your medium is the quickest way to judge whether 316L fits.
Molybdenum is what lets 316L survive coastal air, brackish water and mild chlorides where 304 pits.
Chromium forms the passive film.
Extra nickel balances the molybdenum and keeps the steel austenitic.
Low carbon keeps welds free of sensitisation.
How your 316L fasteners order runs
- 01Enquiry review — we confirm size, standard edition and documents against your MR or drawing.
- 02Heat selection & PMI — the mill certificate is checked against your order; PMI before processing is available on request.
- 03Processing — cutting, machining or bevelling to your specification, with heat numbers marked.
- 04Inspection — your third-party inspector witnesses, or we share photos and test reports.
- 05Packing & dispatch — seaworthy packing from Nhava Sheva (JNPT), Mumbai, FOB or CIF, documents sent before the vessel sails.
Welding & Fabricating SS 316 / 316L Fasteners
SS 316 / 316L welds by all common arc processes. A few points our buyers ask about:
| Matching filler | ER316L (AWS A5.9) |
|---|---|
| Over-alloyed filler | ER309LMo for dissimilar joints |
| Preheat | Not required; keep interpass temperature low |
| Cutting | Thermal or abrasive cutting; grind off heat-tinted edges before welding |
Follow your approved WPS; this is general guidance. See also 316L fittings and 316L flanges for the matching pipe-system parts.
How to Order SS 316 / 316L Fasteners: RFQ Checklist
Get an accurate quote the first time. Copy this list into your enquiry:
- Fastener type, size and length
- Thread form
- Material and marking
- Quantity in sets
- Certificate type
- Delivery port and date
SS 316 / 316L fasteners for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 316 / 316L fasteners — questions buyers ask
Is SS 316 / 316L the same as AISI 316L?
AISI 316L, UNS S31603, W.Nr 1.4404 are names used for SS 316 / 316L (W.Nr / EN numbers and older UNS variants are the closest designations; their limits can differ slightly, so specify the UNS number and ASTM grade on the order). Whichever name is on the enquiry, fasteners: bolts, studs and cap screws to ASTM A193 B8M and nuts to ASTM A194 8M where specified; washers, threaded rod and other types to the purchase specification.
Why use SS 316 / 316L bolts instead of B7 carbon steel?
On SS 316 / 316L flanges in corrosive service, carbon-steel bolts corrode first. Matching-alloy bolting avoids galvanic corrosion and bolt failure.
What nut goes with SS 316 / 316L stud bolts?
ASTM A194 8M heavy hex nuts.
How do I stop SS 316 / 316L bolts galling?
Use an anti-seize compound on threads and nut faces, tighten at moderate speed, and do not reuse galled nuts.
SS 316 / 316L or Duplex 2205 — which should I choose?
SS 316 / 316L is chosen for chloride-bearing process fluids, marine air and pharmaceutical service. Duplex 2205 is the step up when you need more pitting resistance or strength. See the comparison table on this page, or ask us with your process conditions.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026