SS 304L FastenersASTM A193 B8 · Manufacturer, trader & exporter, India
Also sold as AISI 304L · UNS S30403 · W.Nr 1.4307 · Low-carbon 304
SS 304L fasteners — stud bolts, hex bolts, nuts and washers: bolts, studs and cap screws to ASTM A193 B8 and nuts to ASTM A194 8 where specified; washers, threaded rod and other types to the purchase specification. Dimensions to ASME B18 where applicable, or your drawing. It is a low-carbon austenitic chromium-nickel stainless steel, chosen for welded tanks, piping and vessels in general corrosive service. Kanak Steel & Engineering Co. manufactures, trades and exports it from Mumbai; EN 10204 3.1 or 3.2 certificates are available on request / as specified in the PO. Markets we have supplied to include Oman, UAE, Saudi Arabia, Brazil, Argentina, Spain and Chile (India is the home market).
- 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 304L Fasteners?
SS 304L fasteners is a low-carbon austenitic chromium-nickel stainless steel supplied as fasteners (UNS S30403) — bolts, studs and cap screws to ASTM A193 B8 and nuts to ASTM A194 8 where specified; washers, threaded rod and other types to the purchase specification. Buyers specify it for welded tanks, piping and vessels in general corrosive service. It is also sold as AISI 304L, UNS S30403, W.Nr 1.4307.
- What it is
- Low-carbon austenitic chromium-nickel stainless steel
- Material
- ASTM A193 B8 · A194 8
- Dimensions
- ASME B18.2.1 · B18.2.2 · B18.31.2
- Threads
- UNC · UN-8 · metric
- Sizes
- M10 – M64 · ½" – 4"
- Best at
- Welded tanks, piping and vessels in general corrosive service
SS 304L Fasteners Specification & Sizes
| Material | ASTM A193 B8 · A194 8 |
|---|---|
| Scope by type | bolts, studs and cap screws to ASTM A193 B8 and nuts to ASTM A194 8 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 304L Stud Bolts: Grade & Nut Pairing
Pressure bolting in this material is ASTM A193 B8 studs with ASTM A194 8 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 304L Fasteners Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Chromium | As specified |
| Nickel | 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 S30403.
SS 304L 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 S30403 — Annealed plate & sheet.
Density & Physical Properties
| Property | Value |
|---|---|
| Density | 8 g/cm³ |
| Melting range | 1400 – 1450 °C |
| Magnetic | Non-magnetic annealed |
| PREN (approx.) | ≈ 18 |
SS 304L 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 304L 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 304L is most often mixed up with SS 316 / 316L — the table shows which elements tell them apart.
Handheld XRF does not measure carbon or nitrogen, so it cannot tell 304 from 304L: 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 304L | SS 316 / 316L |
|---|---|---|
| Nickel | As specified | As specified |
| Chromium | As specified | As specified |
| Molybdenum | — | As specified |
| Iron | As specified | As specified |
| Manganese | As specified | As specified |
SS 304L fasteners by type
SS 304L Fasteners Applications
SS 304L 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 304L Fasteners vs 304, 316L 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 304L | ASTM A193 B8 · A194 8 | ≈ 18 | Welded tanks, piping and vessels in general corrosive service |
| SS 316 / 316L | ASTM A193 B8M · A194 8M | ≈ 24 | Chloride-bearing process fluids, marine air and pharmaceutical service |
| 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 304L 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 304L fits.
About 18% chromium forms the passive film that makes the steel stainless.
Nickel keeps the structure austenitic — tough at low temperature and easy to form and weld.
The low carbon of the L grade stops carbide forming at grain boundaries during welding, so heavy welds keep their corrosion resistance.
Most mill material today is dual-certified 304/304L, meeting the strength of 304 and the carbon limit of 304L.
How your 304L 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 can be arranged depending on product and requirements, as specified in the PO.
- 03Processing — cutting, machining or bevelling to your specification, with heat numbers marked as specified in the PO.
- 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 304L Fasteners
SS 304L welds by all common arc processes. A few points our buyers ask about:
| Matching filler | ER308L (AWS A5.9) |
|---|---|
| Over-alloyed filler | ER309L 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 304L fittings and 304L flanges for the matching pipe-system parts.
How to Order SS 304L 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 304L fasteners — questions buyers ask
Is SS 304L the same as AISI 304L?
AISI 304L, UNS S30403, W.Nr 1.4307 are names used for SS 304L (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 B8 and nuts to ASTM A194 8 where specified; washers, threaded rod and other types to the purchase specification.
Why use SS 304L bolts instead of B7 carbon steel?
On SS 304L flanges in corrosive service, carbon-steel bolts corrode first. Matching-alloy bolting avoids galvanic corrosion and bolt failure.
What nut goes with SS 304L stud bolts?
ASTM A194 8 heavy hex nuts.
How do I stop SS 304L bolts galling?
Use an anti-seize compound on threads and nut faces, tighten at moderate speed, and do not reuse galled nuts.
SS 304L or Duplex 2205 — which should I choose?
SS 304L is chosen for welded tanks, piping and vessels in general corrosive 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