Type 904L Stainless Steel
Grade 904L Stainless Steel is a high-alloy austenitic stainless steel renowned for its exceptional resistance to corrosion, particularly in harsh and aggressive environments. Often referred to as a “super austenitic” stainless steel, Grade 904L contains high levels of chromium, nickel, molybdenum, and copper, which together provide outstanding durability and performance.
The high chromium and molybdenum content significantly improve resistance to pitting, crevice corrosion, and stress corrosion cracking, especially in chloride-rich environments such as marine and chemical processing applications. The added copper enhances resistance to strong reducing acids, including sulfuric acid.
Unlike standard stainless steels, Grade 904L offers excellent long-term protection against rust, staining, and oxidation, even under extreme conditions. It also has good toughness and impact strength, making it suitable for demanding structural and industrial uses.
Furthermore, Grade 904L Stainless Steel has excellent weldability and formability, allowing it to be fabricated into complex shapes while maintaining its corrosion-resistant properties. It also provides a smooth, attractive finish, making it suitable for both practical and decorative applications.
Applications of Grade 904L Stainless Steel
Grade 904L is widely used in industries where superior corrosion resistance is essential. It is commonly found in:
- Chemical processing equipment
- Heat exchangers and condensers
- Marine and offshore components
- Piping systems and pressure vessels
- Pollution control and scrubber systems
- Pharmaceutical and clean room environments
- Architectural features in harsh climates
Because of its ability to withstand aggressive chemicals, saltwater, and high humidity, Grade 904L is ideal for environments where standard stainless steels such as 304 or 316 may fail over time.
Additionally, Grade 904L is also popular in luxury and high-performance applications where durability, longevity, and appearance are equally important.
Mechanical Properties
| Description | Type 904L |
|---|---|
| Proof Stress 0.2% (MPa) | 220 |
| Tensile strength (MPa) | 490 – 710 |
| Elongation A5 (%) | 35 |
| Hardness | HB: 200 HRB: 90 |
Chemical Composition
| UNS No | N08904 |
| EN | 1.4539 |
| AISI | 904L |
| Carbon (C) | 0.02 |
| Silicon (Si) | 1.00 |
| Manganese (Mn) | 2.00 |
| Phosphorus (P) | 0.045 |
| Sulphur (S) | 0.035 |
| Chromium (Cr) | 19.00 – 23.00 |
| Molybdenum (Mo) | 4.00 – 5.00 |
| Nickel (Ni) | 8.00 – 10.50 |
| Copper (Cu) | 1.00 – 2.00 |
| Nitrogen (N) | 0.10 |
Our Dedicated Stainless Steel Divison in the UK
Based in Wolverhampton (United Kingdom), D.S. Willetts is our dedicated stainless steel division in the UK. D.S. Willetts specialises in the supply of stainless steel plates and profiles. In-house services offered by D.S. Willetts include laser, waterjet, plasma, plate saw, band saw, and guillotine cutting.
Stocked Grades
For more information on the capabilities of D.S. Willetts, please visit the D.S. Willetts website – www.dswilletts.co.uk