Specifications
- Plate, Sheet & Strip: ASTM A240
- ASTM B625
904L Stainless is the most common of the “4% Molybdenum” alloys. It was designed to be an upgrade to 316L and Alloy 20 without incurring the expense of Alloy C276. 904L Stainless has been surpassed in popularity by the “6% Molybdenum” alloys such as AL6XN®. Its availability in round bar is limited to metric sizes in 5mm increments. Consequently, inch-size diameter-headed bolts are relatively expensive to manufacture.
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| Density | lb/in3 | 0.287 |
|---|---|---|
| g/cm3 | 7.95 | |
| Specific Heat | Btu/lb•°F (32-212°F) | 0.11 |
| J/kg•°C (0-100°C) | 450 | |
| Electrical Resistivity | Microhm-in at 68°F | 33.5 |
| Microhm-cm at 20°C | 95.2 | |
| Modules of Elasticity | x 106 psi | 28.0 |
| GPa | 190 | |
| Melting Range | °F | 2372 – 2534 |
| °C | 1300 – 1390 | |
| Thermal Conductivity | Btu•in/ft2 •h•°F | 85 |
| W/m•°C | 12.3 | |
| Specific Gravity | 7.95 | |
| Magnetic Permeability | <1.02 | |
| Temperature Range | |||
| °F | °C | in/in/°F | cm/cm/°C |
| 68 – 212 | 20 – 100 | 8.5 x 10-6 | 15.3 x 10-6 |
| 68- 750 | 20-400 | 9.2 x 10-6 | 16.5 x 10-6 |
| 68-1475 | 20-800 | 10.1 x 10-6 | 18.2 x 10-6 |
| Yield Strength (0.2% Offset) | Ultimate Tensile Strength | Elongation in 2 in. | Hardness | |||
| psi | MPa | psi | MPa | % | Rockwell B | |
| Minimum ASTM & ASME | 31,000 | 220 | 71,000 | 490 | 36 | 70 – 90 |
| Typical Value | 39,500 | 270 | 88,000 | 605 | 50 | 79 |
Typical Values at 68°F (20°C) (minimum values, unless specified)
| Maximum Metal Temperatures | Maximum Allowable Stress per ASME | ||
| °F | °C | ksi | MPa |
| 100 | 38 | 17.8 | 123 |
| 200 | 93 | 16.7 | 115 |
| 300 | 149 | 15.1 | 104 |
| 400 | 204 | 13.8 | 95 |
| 500 | 260 | 12.7 | 88 |
| 600 | 316 | 12.0 | 83 |
| 700 | 371 | 11.4 | 79 |
| Boiling Solution | Corrosion Rate in MPY (mm/a) | |
| Steel Grade 316 | Steel Grade 904L | |
| 20% Acetic Acid | 0.1 (<0.01) | 0.6 (0.02) |
| 45% Formic Acid | 10.9 (0.28) | 7.7 (0.20) |
| 1% Hydrochloric Acid | 226 (5.74) | 21.6 (0.55) |
| 10% Oxalic Acid | 40.1 (1.02) | 27.1 (0.69) |
| 20% Phosphoric Acid | 0.20 (<.01) | 0.5 (0.01) |
| 10% Sodium Bisulfate | 41.5 (1.06) | 8.9 (0.23) |
| 50% Sodium Hydroxide | >100 (>2.5) | 9.6 (0.24) |
| 10% Sulfamic Acid | 63.6 (1.62) | 9.1 (0.23) |
| 10% Sulfuric Acid | 636 (16.2) | 101 (2.57) |
| Alloy | Temperature of Onset of Crevice Corrosion Attack*, °F (°C) |
| 316 | 27 (-3) |
| 317 | 35 (2) |
| 904L | 65 (18) |
| AL-6XN | 113 (45) |
| 625 | 113 (45) |
| AL 29-4C | 125 (52) |
*ASTM Procedure G-48, 10% Ferric Chloride Solution.
| Samples and Test Times to 1000 Hours | |||
| Boiling Solution | Alloy 316 | Alloy 904L | Alloy 20 |
| 42% Magnesium Chloride | Fail | Fail | Fail |
| 33% Lithium Chloride | Fail | Fail | Pass |
| 26% Sodium Chloride | Fail | Pass | Pass |
Fail = Chloride stress corrosion cracks observed. Pass = No cracking observed in testing.
| Intergranular Corrosion Resistance Test Procedure | Corrosion, Rates Mils per Year, (mm/a) | |
| Alloy 316 | Alloy 904L | |
| Copper-Copper Sulfate 16% Sulfuric Acid (ASTM A262 Practice E) Evaluated by Bend Test |
No Fissures | No Fissures |
| Ferric Sulfate Sulfuric Acid (ASTM A262 Practice B) |
35.5 (0.90) |
14.2 (0.36) |
| 65% Nitric Acid (ASTM A262 Practice C) |
34.3 (0.87) |
15.4 (0.39) |
| Steel Grade | Corrosion Rate, mm/year |
| 316L | >6 |
| 904L | 0.47 |
| 254 SMO® | 0.27 |
| 654 SMO® | 0.06 |
*Composition: 20% HNO3 + 4% HF.
| Steel Grade | Corrosion Rate, mm/year |
| 316L | >5 |
| 904L | 1.2 |
| 254 SMO® | 0.05 |
Composition: 54% P2O5, 0.06% HCl, 1.1% HF, 4.0% H2SO4, 0.27% Fe2O3, 0.17% Al2O3, 0.10% SiO2, 0.20% CaO and 0.70% MgO.
| Steel Grade | Corrosion Rate, mm/year |
| 316L | 0.88 |
| 317LMN | 0.29 |
| 904L | 0.06 |
| 254 SMO® | 0.01 |
