SS 304/304L tube fittings are an economical stainless choice for tubing that runs indoors or in dry, non-chloride environments: pneumatic and instrument air lines, water and coolant circuits, lubrication systems, food and beverage equipment and general machinery. Grade 304 gives good resistance to fresh water, mild chemicals and atmospheric corrosion at a lower cost than 316.
Raaj Fittings machines SS 304/304L double ferrule, single ferrule, DIN 2353 bite type and flare fittings, with unions, connectors, elbows, tees and adapters, at our two plants in India, in metric (3–25 mm) and imperial (⅛"–1") tube sizes, for OEMs, panel builders and distributors in the Middle East, Europe and the Americas.
| Material | Stainless steel 304 / 304L (UNS S30400 / S30403) |
|---|---|
| Tube OD | Metric 3 to 25 mm; imperial ⅛" to 1" |
| End connections | Compression tube ends; NPT (ASME B1.20.1), BSPT and BSPP (BS 21 / ISO 7-1) threads |
| Fitting types | Double ferrule, single ferrule, DIN 2353 bite type, flare |
| Manufacturing | CNC machined from bar stock or forgings |
| Certification | EN 10204 3.1 mill test certificate; EN 10204 3.2 on request |
| Element, % | 304 | 304L |
|---|---|---|
| Carbon (C) | 0.08 max | 0.030 max |
| Manganese (Mn) | 2.00 max | 2.00 max |
| Phosphorus (P) | 0.045 max | 0.045 max |
| Sulphur (S) | 0.030 max | 0.030 max |
| Silicon (Si) | 1.00 max | 1.00 max |
| Chromium (Cr) | 18.0 – 20.0 | 18.0 – 20.0 |
| Nickel (Ni) | 8.0 – 11.0 | 8.0 – 12.0 |
| Nitrogen (N) | 0.10 max | 0.10 max |
| Grade | UNS | Werkstoff Nr. | EN designation | JIS |
|---|---|---|---|---|
| 304 | S30400 | 1.4301 | X5CrNi18-10 | SUS 304 |
| 304L | S30403 | 1.4307 / 1.4306 | X2CrNi18-9 / X2CrNi19-11 | SUS 304L |
The choice comes down to chlorides. Indoors, in machinery, and with fresh water, air, oils and most gases, 304 performs well and costs less. Outdoors near the coast, on offshore installations, in washdown areas using chloride-based cleaners, or with any process fluid containing chlorides, specify SS 316/316L tube fittings instead: the molybdenum in 316 prevents the pitting and crevice corrosion that 304 suffers under the nut and ferrules. Always match the fitting material to the tubing material.
Bar stock is PMI-verified and traceable by heat number; threads are gauge-checked and bodies, nuts and ferrules are dimensionally inspected. Every order is supplied with EN 10204 3.1 certificates, with EN 10204 3.2 certification and third-party inspection by the buyer's nominated agency on request.
In dry inland atmospheres, yes. Near the coast, offshore, or where chloride-based cleaners are used, 304 can pit and stain under the nut and ferrules, so SS 316 tube fittings are recommended.
No. Our push-to-connect fittings are made in SS 316 and nickel-plated brass. SS 304 is available in double ferrule, single ferrule, DIN 2353 bite type and flare fittings.
It is best to match the fitting and tubing materials. Mixing grades leaves the 304 component as the weak point for corrosion and can affect how the ferrules grip the tube.
Metric tube ODs from 3 to 25 mm and imperial ODs from ⅛" to 1", with NPT, BSPT or BSPP threaded ends.