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Super Duplex S32550 Bar and Rod Supplier in Mumbai, India
Nicorex Alloys is a supplier of super duplex stainless steel bar and rod products from its Mumbai, India, warehouse. We hold ISO 9001 and ISO 14001 certifications and stock S32550 round bar to ASTM A276, ASTM A479, and ASME SA276/SA479.
UNS S32550 is also designated as F61 (forging grade per ASTM A182), Ferralium 255 (Langley Alloys), Alloy 255, Uranus 52N+ (Industeel), and W.Nr. 1.4507. S32550 is a copper-bearing super duplex stainless steel with a 50:50 austenite-ferrite phase balance. It was the first commercially available super duplex grade, developed in the 1960s. Its 2% copper content gives Ferralium 255 bar unmatched resistance to reducing acids like sulphuric and phosphoric acid that strip passive films off standard super duplex grades. Key alloying elements are 24–27% chromium, 4.5–6.5% nickel, 2.9–3.9% molybdenum, and 0.10–0.25% nitrogen, giving a PREN of about 40.
S32550 mechanical properties per ASTM A276 include a minimum yield strength of 550 MPa (80 ksi) and a minimum tensile strength of 760 MPa (110 ksi). Diameters range from 6 mm to 300 mm in round, hex, flat, square, bright, and forged bars. Finishes include hot rolled, cold drawn, centreless ground, and peeled, shipped in solution-annealed condition with EN 10204/3.1B MTCs and PMI reports. Industries served include oil and gas, chemical processing, marine, desalination, and mining.
S32550 (Ferralium 255) Round Bar and Rod Specifications
| Standards | ASTM A276, A479, ASME SA276, SA479 |
|---|---|
| Forging Grade | ASTM A182 F61 |
| Diameter | 6 mm – 300 mm |
| Length | 1 – 6 metres, custom cut |
| Forms | Round, Hex, Flat, Square, Bright, Black, Forged |
| Finish | Hot Rolled, Cold Drawn, Centreless Ground, Peeled |
| Condition | Solution Annealed |
Chemical Composition of Super Duplex Stainless Steel (SDSS) UNS S32550 Round Bar
| Element | Carbon (C) | Manganese (Mn) | Silicon (Si) | Phosphorus (P) | Sulphur (S) | Chromium (Cr) | Nickel (Ni) | Molybdenum (Mo) | Nitrogen (N) | Copper (Cu) | Iron (Fe) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Percentage (%) | 0.04 max | 1.50 max | 1.00 max | 0.040 max | 0.030 max | 24.0-27.0 | 4.50-6.50 | 2.90-3.90 | 0.10-0.25 | 1.50-2.50 | Balance |
Mechanical Properties of Super Duplex S32550 Bar and Rod
| Property | Tensile Strength (min) | Yield Strength 0.2% (min) | Elongation (min) | Hardness (max) |
|---|---|---|---|---|
| Value | 760 | 550 | 15 | 302 |
| Unit | MPa (110 ksi) | MPa (80 ksi) | % | HBW (32 HRC) |
The yield strength of S32550 is approximately twice that of Alloy 20 (UNS N08020, 276 MPa), making F61 round bar a high-strength alternative in sulphuric acid service where thinner sections cut weight and cost.
Super Duplex Stainless Steel S32550 Equivalent Grades
| Standard / System | UNS | Werkstoff Nr. | EN | AFNOR | ASTM (Bar) | ASTM (Forging) | JIS |
|---|---|---|---|---|---|---|---|
| Designation | S32550 | 1.4507 | X2CrNiMoCuN25-6-3 | Z3CNDU25-07Az | A276, A479 | A182 F61 | SUS 329J4L |
Physical Properties of Alloy 255
| Property | Density | Melting Range | Thermal Conductivity (20°C) | Specific Heat | Electrical Resistivity | Thermal Expansion (20-100°C) | Elastic Modulus |
|---|---|---|---|---|---|---|---|
| Value | 7.81 | 1390-1400 | 14.0 | 475 | 0.85 | 13.5 × 10⁻⁶ | 200 |
| Unit | g/cm³ | °C | W/m·K | J/kg·K | µΩ·m | /°C | GPa |
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Available Forms of Ferralium 255 Bar and Rod
Ferralium 255 Round Bar
S32550 Bright Bar
UNS S32550 Hex Bar
Alloy 255 Flat Bar
S32550 Forged Bar
SDSS UNS S32550 Rod
Hot Working, Cold Forming, and Heat Treatment of Super Duplex S32550 Bar
Hot work S32550 bar at 1100-1200°C. Do not forge below 1000°C. Solution anneal at 1040-1120°C followed by rapid water quench to restore corrosion resistance and phase balance. Cold forming requires higher forces than austenitic grades; stress relief at solution annealing temperature after heavy cold work.
For welding, use ER2553 filler (AWS A5.9). GTAW is preferred for root passes with heat input of 0.5-2.0 kJ/mm and interpass temperature max 150°C. No PWHT is required when parameters are maintained. Avoid prolonged service above 275°C due to embrittlement risk.
Industries and Applications for Super Duplex F61 Bar and Rod
- Valve stems, pump shafts, and wellhead components. S32550 bar is listed in NACE MR0175 for sour service and is machined into choke stems and gate valve internals.
- Agitator shafts in sulphuric acid concentrators, mixer shafts for phosphoric acid reactors, and pump components. The 2% copper gives Ferralium 255 bar a measurable advantage in reducing acid media.
- High-pressure pump shafts for reverse osmosis plants, brine recirculation valve components, and fasteners for MSF evaporator units.
- Propeller shafts, rudder stock, seawater pump impeller shafts, and mooring fitting bolts.
- Slurry pump shafts, agitator spindles, and screen deck fasteners in abrasive, acidic slurries.
- Digester valve shafts, bleach plant bolting, and chemical recovery components.
How to Order S32550 (Ferralium 255) Round Bar and Rod from Nicorex Alloys
- Bar Form - Round bar, hex bar, flat bar, square bar, bright bar, rod
- Grade and UNS - S32550, F61, Ferralium 255
- Standard - ASTM A276, A479, or EN 10088-3
- Diameter and length - In mm or inches
- Surface Finish - Hot rolled, cold drawn, bright, peeled
- Condition - Solution Annealed / Solution Treated & Precipitation Hardened
- Quantity - number of pieces, kg, or MT
- Certificates - EN 10204 3.1, NACE compliance, PMI
- Additional testing - IGC per ASTM A262, Charpy impact, ferrite count
Frequently Asked Questions
What is the Price of S32550 (Ferralium 255) Round Bar per kg in India?
S32550 round bar prices in India generally range from ₹950 to ₹1,700 per kg, influenced by diameter, finish, and copper/nickel surcharges. Ferralium 255 can be more economical than S32760 due to lower nickel content and no tungsten.
What makes Ferralium 255 Different from Other Super Duplex Grades?
Ferralium 255 (S32550) contains approximately 2% copper – more than S32750 (0.5% max Cu) or S32760 (0.5-1.0% Cu). This provides measurably better resistance to acids. It was the first commercially available super duplex grade.
What Welding Filler Metal is Used for S32550 Bar?
ER2553 (AWS A5.9) is the matching filler. GTAW is recommended for root passes with heat input of 0.5-2.0 kJ/mm and interpass temperature max 150°C. No PWHT is required when parameters are maintained.
Can Super Duplex S32550 Replace Alloy 20 in Sulphuric Acid Service?
S32550 offers twice the yield strength (550 MPa vs 276 MPa) of Alloy 20. In sulphuric acid up to 40% concentration and 80°C, S32550 provides comparable or superior corrosion resistance at thinner wall sections. Alloy 20 remains preferable for higher concentrations or boiling conditions.
What Diameter Range is available for S32550 Bar from Nicorex Alloys?
Round bar: 6 mm to 300 mm. Hex bar: 10 mm to 65 mm AF. Lengths 1 to 6 metres with custom cutting available.
Is Ferralium 255 the Same as Uranus 52N+?
Both Ferralium 255 (Langley Alloys) and Uranus 52N+ (Industeel / ArcelorMittal) are trade names for UNS S32550. They share the same UNS, ASTM, and Werkstoff 1.4507 designation. Minor nitrogen control differences may exist between producers, but both meet S32550 composition requirements.