904L stainless steel (UNS N08904) was originally developed to resist corrosion in dilute sulfuric acid. While specific corporate records are not well-documented, it emerged as aerospace steel and was later popularized for marine use by companies like COMEX for diving bells, and eventually by Rolex in 1985 for high-end watches. Because of its high ductility and excellent formability, 904L can be manufactured into fasteners through standard industrial processes.
904L is recognized globally under multiple standards:
- UNS N08904 (U.S. Unified Numbering System)
- 4539 (DIN/Werkstoff Germany)
- X1NiCrMoCu25-20-5 (EN Europe)
- F904L (ASTM/ASME specifications)
Corrosion Resistance of High-Corrosion Resistance 904L Nuts
- Resists pitting, crevice corrosion, and stress corrosion cracking (SCC) in chloride-rich environments
- Superior performance in sulfuric, phosphoric, and nitric acids due to 19-23% Cr, 23-28% Ni, and 4-5% Mo
Mechanical Properties Of 904L hex nuts heavy hex nuts
- Tensile Strength: ≥490 MPa | Yield Strength: ≥215 MPa | Elongation: ≥35% 34.
- Density: 8.0 g/cm³ | Hardness: ~200 HB (solution-annealed) 36.
Fabrication Advantages of 904L 1.4539 Nuts
- Excellent weldability with 904L filler rods and compatibility with TIG/MIG methods
- Non-magnetic and retains ductility after cold working
3. Standards and Specifications of 904L nuts ,they are comply with:
- ASTM A194/A194M: Standard for stainless steel nuts for high-pressure/temperature service.
- ASME SB649: Bars and forgings for piping components
- DIN 934/936: Metric hex nuts and flange nuts
Key Applications of ASTM A194 904L Nuts as below :
Alloy 1.4539 Hex Nut in Chemical & Petrochemical application
- Reactors, heat exchangers, and piping in sulfuric acid production
DIN 934 904L Nut in Pharmaceutical application
- Non-reactive containers and sterile equipment
UNS N08904 Fasteners in Marine & Offshore application :
- Seawater handling systems and subsea fasteners
Solution Annealing 904L hex nut ,heavy hex nut in Power Generation application:
- Flue gas desulfurization (FGD) scrubbers and ductwork
Suggested Tables Of 904L stainless steel hex nut
Table 1: Chemical Composition of 904L (wt%)
| C ≤0.02 | Cr 19-23 | Ni 23-28 | Mo 4-5 | Cu 1-2 | Fe Balance | 24
Table 2: Mechanical Properties
| Tensile Strength | Yield Strength | Elongation | Hardness | |
| ≥490 MPa | ≥215 MPa | ≥35% | 200 HB | 34 |
Conclusion
904L stainless steel nuts offer unmatched corrosion resistance and mechanical stability for critical applications. By adhering to ASTM/ASME standards and leveraging their unique alloy composition, these nuts ensure reliability in the most demanding environments. For industries prioritizing longevity and safety, 904L remains the material of choice.
