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Stainless Steel 904L Bolts are high-performance fasteners engineered for extreme corrosive environments where conventional stainless steels like 304 and 316 fail over time. Manufactured from super austenitic stainless steel UNS N08904, these bolts offer exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking, especially in chloride-rich and acidic conditions. They are widely used in chemical processing plants, offshore oil & gas platforms, seawater systems, and pharmaceutical equipment, where long-term structural integrity is critical.
These bolts comply with international standards such as ISO 3506, ASTM B649, and DIN specifications, ensuring dimensional accuracy and mechanical reliability under high-load conditions. The alloy’s high nickel and molybdenum content significantly enhances corrosion resistance in sulfuric and phosphoric acid environments.
KK Fasteners supplies Stainless Steel 904L Bolts to global industrial clients with strict material traceability and inspection protocols, ensuring consistent performance across demanding applications in more than 30 countries.
| Parameter | Details |
|---|---|
| Material Grade | UNS N08904 (904L Stainless Steel) |
| Equivalent Standards | ASTM B649, EN 1.4539, ISO 3506 |
| Types | Hex Head Bolts, Stud Bolts, Socket Head Cap Screws, U Bolts |
| Size Range | M6 to M100 / 1/4” to 4” |
| Thread Type | Metric (MM), UNC, UNF, BSW |
| Surface Finish | Bright, Polished, Passivated |
| Hardness | Max 90 HRB |
| Tensile Strength | 490–700 MPa |
| Temperature Range | -196°C to +400°C |
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | |
| 904L | min. | – | – | – | – | – | 19.0 | 4.00 | 23.00 | 0.10 |
| max. | 0.20 | 2.00 | 1.00 | 0.045 | 0.035 | 23.0 | 5.00 | 28.00 | 0.25 | |
| Grade | Tensile Strength (MPa) min | Yield Strength 0.2% Proof (MPa) min | Elongation (% in 50mm) min | Hardness | |
| Rockwell B (HR B) max | Brinell (HB) max | ||||
| 904L | 490 | 220 | 35 | 70-90 typical | – |
| Grade | UNS No | Old British | Euronorm | Swedish SS | Japanese JIS | ||
| BS | En | No | Name | ||||
| 904L | N08904 | 904S13 | X1NiCrMoCu25-20-5 | 1.4539 | – | – | SUS 890L |
| Class 150 Flanges ASME B16.5 (Stud bolt sizes) | Length of Stud Bolts | |||||||
| NPS | The diameter of 904L Stainless Steel Bolts Circle | Outside Diameter of Flange | Diameter of 904L Stainless Steel Bolts | Ring Joint | Raised Face 0.06 in |
|||
| 1/2 | 2 3/8 | 3 1/2 | 1/2 | – | 2 1/4 | |||
| 3/4 | 2 3/4 | 3 7/8 | 1/2 | – | 2 1/2 | |||
| 1 | 3 1/8 | 4 1/4 | 1/2 | 3 | 2 1/2 | |||
| 1 1/4 | 3 1/2 | 4 5/8 | 1/2 | 3 1/4 | 2 3/4 | |||
| 1 1/2 | 3 7/8 | 5 | 1/2 | 3 1/4 | 2 3/4 | |||
| 2 | 4 3/4 | 6 | 5/8 | 3 3/4 | 3 1/4 | |||
| 2 1/2 | 5 1/2 | 7 | 5/8 | 4 | 3 1/2 | |||
| 3 | 6 | 7 1/2 | 5/8 | 4 | 3 1/2 | |||
| 3 1/2 | 7 | 8 1/2 | 5/8 | 4 | 3 1/2 | |||
| 4 | 7 1/2 | 9 | 5/8 | 4 | 3 1/2 | |||
| 5 | 8 1/2 | 10 | 3/4 | 4 1/4 | 3 3/4 | |||
| 6 | 9 1/2 | 11 | 3/4 | 4 1/2 | 4 | |||
| 8 | 11 3/4 | 13 1/2 | 3/4 | 4 3/4 | 4 1/4 | |||
| 10 | 14 3/4 | 16 | 7/8 | 5 | 4 1/2 | |||
| 12 | 17 | 19 | 7/8 | 5 1/4 | 4 3/4 | |||
| 14 | 18 3/4 | 21 | 1 | 5 3/4 | 5 1/4 | |||
| 16 | 21 1/4 | 23 1/2 | 1 | 5 3/4 | 5 1/4 | |||
| 18 | 22 3/4 | 25 | 1 1/8 | 6 1/4 | 5 3/4 | |||
| 20 | 25 | 27 1/2 | 1 1/8 | 6 3/4 | 6 1/4 | |||
| 24 | 29 1/2 | 32 | 1 1/4 | 7 1/4 | 6 3/4 | |||
| Class 300 Flanges ASME B16.5 | Length of Stud Bolts | |||||||
| NPS | The diameter of 904L Stainless Steel Bolts Circle | Outside Diameter of Flange | Diameter of Bolts | The diameter of 904L Stainless Steel Bolts Holes | Ring Joint | |||
| 1/2 | 2 5/8 | 3 3/4 | 1/2 | 5/8 | 3 | |||
| 3/4 | 3 1/4 | 4 5/8 | 5/8 | 3/4 | 3 1/2 | |||
| 1 | 3 1/2 | 4 7/8 | 5/8 | 3/4 | 3 1/2 | |||
| 1 1/4 | 3 7/8 | 5 1/4 | 5/8 | 3/4 | 3 3/4 | |||
| 1 1/2 | 4 1/2 | 6 1/8 | 3/4 | 7/8 | 4 | |||
| 2 | 5 | 6 1/2 | 5/8 | 3/4 | 4 | |||
| 2 1/2 | 5 7/8 | 7 1/2 | 3/4 | 7/8 | 4 1/2 | |||
| 3 | 6 5/8 | 8 1/4 | 3/4 | 7/8 | 4 3/4 | |||
| 3 1/2 | 7 1/4 | 9 | 3/4 | 7/8 | 5 | |||
| 4 | 7 7/8 | 10 | 3/4 | 7/8 | 5 | |||
| 5 | 9 1/4 | 11 | 3/4 | 7/8 | 5 1/4 | |||
| 6 | 10 5/8 | 12 1/2 | 3/4 | 7/8 | 5 1/2 | |||
| 8 | 13 | 15 | 7/8 | 1 | 6 | |||
| 10 | 15 1/4 | 17 1/2 | 1 | 1 1/8 | 6 3/4 | |||
| 12 | 17 3/4 | 20 1/2 | 1 1/8 | 1 1/4 | 7 1/4 | |||
| 14 | 20 1/4 | 23 | 1 1/8 | 1 1/4 | 7 1/2 | |||
| 16 | 22 1/2 | 25 1/2 | 1 1/4 | 1 3/8 | 8 | |||
| 18 | 24 3/4 | 28 | 1 1/4 | 1 3/8 | 8 1/4 | |||
| 20 | 27 | 30 1/2 | 1 1/4 | 1 3/8 | 8 3/4 | |||
| 24 | 32 | 36 | 1 1/2 | 1 5/8 | 10 | |||
All measurements in millimeters
| NOMINAL SIZE (D) | BODY DIAMETER | HEAD THICKNEASTM A193 | ACROASTM A193 THE FLATS | ACROASTM A193 CORNERS | ||||
|---|---|---|---|---|---|---|---|---|
| D (MAX) | D (MIN) | H (MAX) | H (MIN) | F (MAX) | F (MIN) | C (MAX) | C (MIN) | |
| m10 | 10.00 | 9.78 | 6.63 | 6.17 | 17.00 | 15.73 | 18.48 | 17.77 |
| m12 | 12.00 | 11.73 | 7.76 | 4.24 | 19.00 | 17.73 | 20.78 | 20.03 |
| m14 | 14.00 | 13.73 | 9.09 | 8.51 | 22.00 | 20.67 | 24.25 | 23.35 |
| m16 | 16.00 | 15.73 | 10.32 | 9.68 | 24.00 | 23.67 | 27.71 | 26.75 |
| m20 | 20.00 | 19.67 | 12.88 | 12.12 | 30.00 | 29.16 | 34.64 | 32.95 |
| m24 | 24.00 | 23.67 | 15.44 | 14.56 | 36.00 | 35.00 | 41.57 | 39.55 |
| m30 | 30.00 | 29.67 | 19.48 | 17.92 | 46.00 | 45.00 | 53.12 | 50.85 |
| m36 | 36.00 | 35.61 | 23.38 | 21.63 | 55.00 | 53.80 | 63.51 | 60.79 |
| m42 | 42.00 | 41.38 | 26.97 | 25.03 | 65.00 | 62.90 | 75.06 | 71.71 |
| m48 | 48.00 | 47.38 | 31.07 | 28.93 | 75.00 | 72.60 | 86.60 | 82.76 |
| m56 | 56.00 | 55.26 | 36.2 | 33.80 | 85.00 | 82.20 | 98.15 | 93.71 |
| m64 | 64.00 | 63.26 | 41.32 | 38.68 | 95.00 | 91.80 | 109.70 | 104.65 |
| m72 | 72.00 | 71.26 | 46.45 | 43.55 | 105.00 | 101.40 | 121.24 | 115.60 |
| m80 | 80.00 | 79.26 | 51.58 | 48.42 | 115.00 | 111.00 | 132.72 | 126.54 |
| m90 | 90.00 | 89.13 | 57.74 | 54.26 | 130.00 | 125.50 | 150.11 | 143.07 |
| m100 | 90.00 | 99.13 | 63.9 | 60.10 | 145.00 | 140.00 | 167.43 | 159.60 |
Stainless Steel 904L Bolts are used in industries where corrosion, heat, and chemical exposure demand long-term fastener reliability.
Stainless Steel 904L Bolts are manufactured using cold forging and precision CNC threading processes to ensure dimensional accuracy and uniform grain structure. Heat treatment is carefully controlled to maintain mechanical balance between strength and ductility.
Each batch undergoes strict inspection, including dimensional verification, tensile testing, hardness testing, and surface finish evaluation. Material traceability is maintained through heat numbers and batch records. KK Fasteners follows ISO 9001:2015 quality management systems, ensuring every bolt meets global industrial compliance requirements before dispatch.
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Stainless Steel 904L Bolts are high-alloy fasteners made from super austenitic stainless steel UNS N08904. They are specifically designed for highly corrosive environments such as chemical processing plants, offshore platforms, and seawater systems where standard stainless steel bolts may fail.
Yes, 904L offers superior corrosion resistance compared to 316L due to its higher nickel, chromium, and molybdenum content. It performs better in acidic environments, particularly in sulfuric acid and chloride-rich conditions, making it suitable for more aggressive industrial applications.
Stainless Steel 904L Bolts typically conform to standards such as ASTM B649, ISO 3506, and EN 1.4539. These standards define chemical composition, mechanical properties, and dimensional tolerances to ensure consistent performance in industrial applications.
They are widely used in chemical processing equipment, offshore oil and gas platforms, marine systems, desalination plants, and pharmaceutical manufacturing setups where resistance to corrosion and chemical exposure is essential.
A reliable supplier should offer ISO-certified manufacturing, full material traceability, and third-party inspection reports. Companies like KK Fasteners supply globally with documented quality assurance processes and consistent export capabilities across multiple industries.
Stainless Steel 904L Bolts are critical for industries where corrosion failure is not an option. With strict quality control, certified materials, and global supply capability, KK Fasteners ensures reliable fastening solutions for demanding engineering environments. Contact the technical team to request specifications, pricing, or customized export support for your project requirements.
