Manufacturer, supplier and exporter of SS 304, 316, 316L, 904L and duplex nuts in every profile — hex, lock, flange, weld, nylock and more. Certified to ASTM, DIN and ISO, engineered for a lifetime of corrosion-free performance.
ASTM / DIN / ISO Certified • M2–M33 & Custom Sizes • Worldwide Export • In-house QC Lab
Stainless steel nuts are the small components that decide whether a joint survives a decade or fails in a season. At Unifit Fastener, we manufacture and supply premium stainless steel nuts engineered for the environments that destroy ordinary hardware — coastal salt spray, chemical plants, high-temperature machinery and heavy-vibration assemblies. Produced from carefully selected austenitic and duplex alloys such as SS 304, 316, 316L, 317L and 904L, our nuts form a self-healing passive oxide layer that resists rust, pitting and chloride attack long after zinc-plated alternatives have corroded away. Our range spans every practical profile — hex, heavy hex, lock, nylock, flange, weld, dome, castle, coupling and eye nuts — in metric M2 to M33 and custom sizes, with coarse or fine threads to your drawing. Every batch is manufactured to ASTM, DIN, ISO and BS standards and verified in our in-house lab for tensile strength, hardness and intergranular corrosion resistance. Whether you are an OEM, EPC contractor, distributor or exporter, Unifit Fastener delivers documented quality, consistent supply and fast global dispatch — so the smallest part of your assembly is never the weakest.
| Material | Stainless Steel — SS 202, 304, 304L, 316, 316L, 317L, 321, 347, 904L, 310, Duplex 2205 & 410 |
|---|---|
| Standards | ASTM A194 / A193, ASME SF594, DIN, ISO, BS, EN, GB, IS & WERKSTOFF equivalents |
| Nut Standards | Hex (DIN 934 / ISO 4032), Lock (DIN 439), Nylock (DIN 985), Flange (DIN 6923), Square (DIN 557/562), Weld (DIN 929) |
| Size Range | Metric M2 to M33 (Imperial #2 to 1-1/4") — custom sizes on request |
| Length / Thickness | Standard profiles from 3 mm; heavy-pattern nuts to order |
| Threads | Coarse & fine — UNC, UNF, BSF, BSW, UNEF, metric fine |
| Property Class | A2-70, A4-70, A2-80, A4-80 and grade-specific classes |
| Heat Treatment | Annealing, stress relieving, solution annealing, quenching & tempering, case hardening |
| Finish | Passivated (natural), electropolished, bright zinc plated, black oxide, PTFE / hot-dip on request |
| Testing | Tensile, proof-load, hardness, PMI, salt-spray & intergranular corrosion (ASTM A262) |
From offshore platforms to food-processing lines, Unifit stainless steel nuts hold mission-critical assemblies together wherever strength, hygiene or corrosion resistance is non-negotiable.
| Industry | Why Stainless Steel Nuts | Recommended Grade |
|---|---|---|
| Marine & Offshore | Constant saltwater and spray exposure | SS 316 / Duplex 2205 |
| Oil, Gas & Petrochemical | Corrosive media, high pressure & heat | SS 316L / 904L / Duplex |
| Construction & Infrastructure | Structural steel & architectural fixings | SS 304 / 316 |
| Automotive & Machinery | Vibration and maintenance-free joints | SS 304 + Nylock/Flange |
| Chemical Processing | Acid and chloride resistance | SS 316L / 317L / 904L |
| Food, Dairy & Pharma | Hygienic, non-toxic, cleanable | SS 304 / 316L |
| Renewable Energy (Solar/Wind) | Long-term outdoor exposure | SS 304 / 316 |
| Water Treatment & Desalination | Continuous wet, chloride-rich service | SS 316 / Duplex |
The most common buyer question, answered at a glance. This block is structured to win a featured snippet for “difference between 304 and 316 nuts”.
| Property | SS 304 | SS 316 | Duplex 2205 |
|---|---|---|---|
| Molybdenum content | None | 2–3% (added) | ~3% |
| Chloride / salt resistance | Moderate | Excellent | Superior |
| Relative strength | Standard | Standard | ~2× higher yield |
| Typical cost | Lowest | Higher | Highest |
| Best for | Indoor / general | Marine / chemical | Offshore / high-pressure |
Consistency comes from a controlled process. Here is how every Unifit nut is made and verified:
Unifit stainless steel nuts are manufactured and controlled to internationally recognised standards, and every consignment is backed by documentation:
The price of stainless steel nuts depends on the grade, size, standard, finish, and quantity ordered. Below are typical market price ranges in India for standard hex nuts.
| Stainless Steel Grade | Approx. Price (INR/kg) |
|---|---|
| SS 304 / 304L Nuts | ₹180 – ₹260/kg |
| SS 316 / 316L Nuts | ₹320 – ₹500/kg |
| SS 310 / 310S Nuts | ₹500 – ₹750/kg |
| SS 317 / 317L Nuts | ₹550 – ₹850/kg |
| SS 321 Nuts | ₹350 – ₹550/kg |
| SS 904L Nuts | ₹900 – ₹1,600/kg |
| Duplex 2205 Nuts | ₹600 – ₹1,000/kg |
| Super Duplex 2507 Nuts | ₹1,200 – ₹2,200/kg |
A. Stainless steel nuts are highly corrosion-resistant rather than fully rust-proof. A chromium-oxide passive layer continuously reforms to protect the surface, so grades like SS 304 and SS 316 resist rust and staining even in wet or chemical environments — far outlasting zinc-plated steel.
A. The key difference is molybdenum. SS 316 contains 2–3% molybdenum, giving it much stronger resistance to chlorides, salt water and acids. SS 304 is ideal for indoor and general use, while SS 316 is the standard choice for marine, coastal and chemical applications.
A. SS 316 or SS 316L is recommended for marine and coastal environments because of its chloride resistance. For offshore, high-pressure or especially aggressive conditions, Duplex 2205 offers even greater strength and corrosion protection.
A. Unifit supplies metric M2 to M33 and custom sizes, with coarse or fine threads. Standards include DIN 934, ISO 4032, ASTM A194, DIN 439 (lock), DIN 985 (nylock), DIN 6923 (flange) and more — covering hex, heavy hex, lock, flange, weld, square and specialty nuts.
A. Yes, but choose compatible materials to avoid galvanic corrosion. Pairing stainless nuts with stainless bolts of a similar grade is safest. When mixing metals in wet environments, use isolation washers or coatings to prevent galvanic reactions.
