Seamless Stainless Steel TP904L Tube
UNS N08904 Super Austenitic Stainless Steel for Sulfuric Acid & Severe Corrosion Resistance
1. What is a Seamless TP904L Stainless Steel Tube?
Seamless TP904L stainless steel tube (UNS N08904 / W.Nr. 1.4539) is a high-alloy super austenitic stainless steel tube engineered for the most aggressive corrosive environments, particularly sulfuric acid (H₂SO₄) and mixed acid media.
Manufactured from a solid billet using a seamless process (hot piercing + cold drawing/finishing), TP904L provides:
- No weld seam → eliminates weld-related corrosion risks
- Uniform microstructure → consistent corrosion resistance
- Superior pressure resistance → ideal for critical piping systems
The grade is characterized by:
- HighChromium (Cr)andNickel (Ni)content
- Addition of Molybdenum (Mo)andCopper (Cu)
- Very low carbon content (≤ 0.020%)
This unique composition ensures excellent resistance to reduction acids, especially sulfuric acid, while maintaining weldability and structural stability.
2. Key Features & Technical Advantages
Outstanding Sulfuric Acid Resistance
Specifically engineered for sulfuric acid service across a wide concentration range (under moderate temperatures). Also performs well in phosphoric acid and acetic acidenvironments.
Excellent Pitting & Crevice Corrosion Resistance
High Mo (4–5%) and Cu content significantly improve resistance to localized corrosion, with a high PREN (Pitting Resistance Equivalent Number).
Superior Resistance to Chloride SCC
Nickel content (23–28%) provides strong resistance to chloride-induced stress corrosion cracking (SCC), making it suitable for marine and industrial environments.
Excellent Weldability & Fabricability
Low carbon content prevents sensitization, ensuring corrosion resistance in the heat-affected zone (HAZ) without the need for post-weld heat treatment.
Non-Magnetic Austenitic Structure
Remains non-magnetic even after cold working, suitable for specialized industrial and electronic applications.
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Stainless Steel 317.
Stainless Steel 904L is specifically designed to maintain its strength and shape in high-stress, corrosive environments.
These physical properties highlight the material’s ability to perform reliably under a wide range of conditions.
These physical properties highlight the material’s ability to perform reliably under a wide range of conditions.
Common Industrial Applications
TP904L seamless tubes are widely used in highly corrosive and acid-rich environments, including:
Chemical & Acid Processing
- Sulfuric acid production systems
- Phosphoric and acetic acid equipment
- Heat exchangers and reactors
Oil & Gas / Refinery
- Sour gas handling systems
- Gas scrubbing equipment
- Corrosion-resistant piping
Environmental Engineering
- Flue Gas Desulfurization (FGD) systems
- Scrubbers and exhaust treatment systems
Pulp & Paper Industry
- Bleaching systems
- Chemical washing units
Pharmaceutical & Food Industry
- High-purity, corrosion-free process systems
Advanced Manufacturing Process
- Raw Material Selection & Billet Heating
High-quality alloy billets ensure consistent composition and performance. - Hot Piercing & Seamless Forming
Produces hollow tubes without weld seams or weak points. - Cold Drawing / Cold Rolling
Achieves precise dimensions and superior surface finish. - Solution Annealing
Restores corrosion resistance and mechanical properties. - Full Non-Destructive Testing (NDT)
- Ultrasonic Testing (UT)
- Eddy Current Testing (ET)
- Hydrostatic Testing
100% Quality Assurance & Certification
We provide full quality control and certification to meet global project requirements:
- EN 10204 3.1 / 3.2 Material Test Certificates (MTC)
- 100% PMI (Positive Material Identification)
- NDT Testing: UT, ET, Hydrostatic Test
- Corrosion Testing:
- Pitting corrosion test
- Crevice corrosion test
- Intergranular corrosion (IGC) per ASTM A262
- Third-Party Inspection:
ABS, TÜV, BV, DNV, SGS available upon request
