Specifications
- Plate, Sheet & Strip: ASTM A240
- Rod & Bar: ASTM A479
Ferralium 255 is a super duplex stainless which has a pitting resistance number greater than 40. Due to its copper content, it resists corrosion better than the other super duplexes, particularly in seawater applications.
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| Density at 20°C | 7.81 g/cc | |
| Mean Coefficient of Thermal Expansion (m/m/°C) | 20 – 100°C | 11.1 x 10-6 |
| 20 – 200°C | 11.5 x 10-6 | |
| 20 – 300°C | 12.0 x 10-6 | |
| Thermal Conductivity (W/m•K) | 20°C | 14.2 |
| 100°C | 16.3 | |
| 200°C | 18.4 | |
| Specific Electrical Resistance (Ω-m) | 20°C | 0.80 |
| 100°C | 0.88 | |
| 200°C | 0.93 | |
| Specific Heat (J/kg•K) | 20°C | 475 |
| 100°C | 500 | |
| 200°C | 532 | |
| Magnetic Permeability | 33 | |
| Young’s Modulus (kN/mm2) | 199 x 103 | |
| Compression Modulus (N/mm2) | 150 x 103 | |
| Torsional Modulus (N/mm2) | 75 x 103 | |
| Fracture Toughness, KQ (N/mm2 – m1⁄2) | 98 | |
| Poisson’s Ratio | 0.32 | |
| Bars up to and including 4.0” (100mm) diameter or section | Bars greater than 4.0” (100mm) and up to 12.0” (300mm) diameter or section |
Bars greater than 12.0” (300mm) diameter or section |
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| 0.2% Proof Stress | 586 N/mm2 | 85ksi | 586 N/mm2 | 85ksi | 570 N/mm2 | 83ksi |
| Tensile Strength | 790 N/mm2 | 114.5ksi | 790 N/mm2 | 114.5ksi | 760 N/mm2 | 110ksi |
| Elongation, 5.65√S0 and 4D |
25% | — | 25% | — | 25% | — |
| Reduction of Area | 50% | — | 50% | — | 50% | — |
| Hardness (Brinell) | 220-270 | — | 220-270 | — | 220-270 | — |
| Impact Strength (Room Temp) |
80J | 59 ft.lb | 80J | 59 ft.lb | 80J | 59 ft.lb |
| Impact Strength (-46°C) |
45J av (35J min) |
33 ft.lb av (25.8 ft.lb min) |
45J av (35J min) |
33 ft.lb av (25.8 ft.lb min) |
45J av (35J min) |
33 ft.lb av (25.8 ft.lb min) |
| Ferralium® 255-SD50 | S17400 (17- 4PH) |
S32205 | N07718 | S31254 | |
| Pitting Resistance Equivalent number | >40 | 16 | 34 | 31 | 43 |
| 0.2% Proof Strength (N/mm2) | 586 | 1100 | 510 | 500 | 325 |
| Corrosion Rate (mm/year) – Seawater | <0.01 | ~1 | <0.01 | <0.01 | <0.01 |
| Corrosion Rate (mm/year) – 10% sulphuric acid at 80°C B | <0.15 | 10 | 0.4 | <0.15 | 1.5 |
| Corrosion Rate (mm/year) – Boiling 50% nitric acid | <0.15 | <0.15 | <0.15 | <0.15 | 0.4 |
| Wear Properties related to Hardness (HRC), maximum | 28 | 38 | 25 | 20 | 20 |
| Operation | Cutting Speed m/min (ft/min) |
Feed Rate mm/rev (in/rev) |
Depth of cut mm (in) |
| Milling | 40 (130) | 0.05 – 0.13 mm/tooth 0.02 – 0.005 in/tooth |
0.5 – 6.0 (0.02 – 0.25) |
| Drilling 6.4mm (1/4″) dia | 250 rpm | 0.075 (0.003) | — |
| Drilling 25.4mm (1″) dia | 150 rpm | 0.28 (0.011) | — |
| Turning – Roughing | 30 – 45 (100 – 150) | 0.2-0.38 (0.008 – 0.015) | 3 (0.125) |
| Turning – Finishing | 50 – 60 (165 – 200) | 0.13-0.20 (0.005 – 0.008) | 0.5 (0.02) |
| Tooling | Milling/Turning: Carbide (SANDVIK GC 235, SECOT25M) | ||
| Drilling: HSS, point angle 118°, chisel angle 120° | |||
