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904L Stainless Steel Round Bar Supplier in Mumbai, India
Nicorex Alloys is an ISO 9001 and ISO 14001 certified supplier and stockist based in Mumbai, India. We supply UNS N08904 conforming to the ASTM B649 / ASME SB649 for bar and wire, and ASTM A276 / A479 for general bar.
904L stainless steel round bar (UNS N08904 / W.Nr. 1.4539) is a super-austenitic grade combining 25% nickel, 4.5% molybdenum, and 1.5% copper to resist dilute and moderately concentrated sulphuric acid at temperatures up to approximately 35°C under controlled conditions. This copper-bearing super-austenitic grade also handles phosphoric acid and hot organic acids. 904L is a non-stabilised, fully austenitic grade with a non-magnetic structure, high toughness from ambient down to cryogenic temperatures, and good formability for cold bending and drawing operations. The chromium-nickel-molybdenum-copper composition resists pitting, crevice corrosion, oxidation, stress corrosion cracking, and general attack in chloride-bearing and reducing-acid media. PREN reaches approximately 35, well above 316L at ~24. Mechanical properties as per ASTM B649 include a minimum tensile strength of 490 MPa (71 ksi), yield strength of 220 MPa (31 ksi), and 35% min elongation with 90 HRB max hardness.
Diameters of ASTM B649 UNS N08904 bars range from 3 mm to 350 mm in solution-annealed condition (1060–1140°C, water quench). Each of our round bars comes with EN 10204 3.1 mill test certificates. Key industries include chemical processing, oil and gas, marine, desalination, pulp and paper, pharmaceutical, and power generation. UNS N08904 round bars are commonly referred to as SS 904L, Alloy 904L, AISI 904L, SUS 904L, and X1NiCrMoCu25-20-5.
904L Stainless Steel Bar & Rod Specifications
| Specification | ASTM B649 / ASME SB649, ASTM A276 / A479 |
|---|---|
| Forms | Round, Hex, Flat, Square Bar |
| Diameter | 3 mm – 350 mm |
| Length | 1000 – 6000 mm, custom cut |
| Condition | Solution Annealed (1060–1140°C, water quench) |
| Finish | Black, Bright Polished, Rough Turned, Centreless Ground, BA |
Chemical Composition of 904L Stainless Steel Bar
| Nickel (Ni) | Chromium (Cr) | Molybdenum (Mo) | Copper (Cu) | Carbon (C) | Manganese (Mn) | Silicon (Si) | Phosphorus (P) | Sulphur (S) | Iron (Fe) |
|---|---|---|---|---|---|---|---|---|---|
| 23.0 – 28.0 | 19.0 – 23.0 | 4.0 – 5.0 | 1.0 – 2.0 | 0.020 max | 2.0 max | 1.0 max | 0.045 max | 0.035 max | Balance |
Mechanical Properties of ASTM B649 904L Bar
| Property | Tensile Strength (min) | Yield Strength 0.2% Offset (min) | Elongation in 2 in. (min) | Hardness (max) |
|---|---|---|---|---|
| Value | 490 MPa (71 ksi) | 220 MPa (31 ksi) | 35% min | 90 HRB |
Physical Properties of 904L Stainless Steel Bar
| Property | Density | Melting Range | Elastic Modulus | Thermal Expansion (20–100°C) | Thermal Conductivity (20°C) | Electrical Resistivity | Specific Heat | Magnetic Permeability |
|---|---|---|---|---|---|---|---|---|
| Value | 8.0 | 1300–1390 | 190 | 15.0 × 10⁻⁶ | 11.5 | 95 | 450 | Non-magnetic (austenitic) |
| Unit | g/cm³ | °C | GPa | /°C | W/m·K | µΩ·cm | J/kg·K | – |
904L Round Bar Equivalent Grades
| Property | UNS | Werkstoff Nr. | EN | JIS | Standard (Bar) | Standard (Plate/Pipe) | ASME | AFNOR |
|---|---|---|---|---|---|---|---|---|
| Specification | N08904 | 1.4539 | X1NiCrMoCu25-20-5 | SUS 904L | B649 | B625, B673, B677 | SB649, SB625, SB673, SB677 | Z2 NCDU 25-20 |
Get 904L Stainless Steel Bar at Competitive Prices
Available Forms of 904L Stainless Steel Bar
904L Round Bar
904L Hex Bar
904L Flat Bar
904L Rectangular Bar
904L Bright Bar
904L Square Bar
904L Rods
Pitting and Crevice Corrosion Performance of 904L Bar
904L bar delivers a PREN of approximately 35 (formula: %Cr + 3.3×%Mo + 16×%N), well above 316L at ~24. Copper provides resistance in reducing acids: sulphuric acid across the full concentration range up to 35°C, phosphoric acid, and hot acetic acid. The 25% Ni content gives improved immunity to chloride stress corrosion cracking versus 8% Ni in 304L.
| Grade | 316L | 904L | 2205 Duplex | 254 SMO |
|---|---|---|---|---|
| PREN | ~24 | ~35 | ~35 | ~43 |
| Ni % | 10–14 | 23–28 | 4.5–6.5 | 17.5–18.5 |
| SCC Resistance | Poor | Good | Excellent | Good |
904L is not suitable for nitric acid or strong oxidising environments. Max service temperature as per ASME is approximately 400°C; structural stability degrades above this due to intermetallic precipitation.
Hot Working, Welding & Machining of 904L Bar Stock
It is recommended to hot work this bar at 850–1150°C, and solution anneal at 1060–1140°C with rapid cooling below 700°C. Between 800–900°C, intermetallic phases form within minutes, so rapid cooling through this range is critical.
Weld with matching 904L filler (20 25 CuL electrode). No preheat or PWHT required. Machining requires rigid setups and positive rake angles. The austenitic structure work-hardens more than 304/316, so use reduced cutting speeds in the solution-annealed condition.
Industries and Applications of 904L Round Bar
- Sulphuric acid reactor valve stems, phosphoric acid plant pump shafts, pickling line components, and agitator shafts in acid mixing tanks.
- Heat exchanger tubesheet bolting, crude oil distillation column internals, and sour-gas valve components per NACE MR0175.
- Seawater pump shafts, desalination plant hardware, and offshore platform fasteners. The 25% Ni content resists chloride SCC in warm seawater.
- Bleach plant equipment, shafts and chlorine dioxide generator components.
- Sterile tank agitator shafts and process vessel fasteners. Low carbon minimises contamination risk.
- Flue gas desulphurisation scrubber hardware and wet scrubber pump shafts.
How to Order 904L Stainless Steel Round Bar
- Product Form Round bar, hex bar, flat bar, square bar, bright bar
- Specification ASTM B649 / ASME SB649
- Grade UNS N08904 (904L)
- Diameter / Size & Tolerance H9–H12
- Length & cutting tolerance
- Condition Solution Annealed
- Surface Finish Black, bright, polished, centreless ground, BA
- Testing IGC per ASTM A262, PMI
- Documentation EN 10204 3.1 MTC, NACE certificate if required
- Quantity and delivery schedule