ASME SA312 UNS N08904 / TP904L Stainless Steel Pipe DIN 1.4539 Seamless Pipe for Industry

ASME SA312 TP904L / UNS N08904 Stainless Steel Seamless Pipe for Oil and Gas Industry
 
 

ASME SA312 UNS N08904 / TP904L / DIN 1.4539 seamless pipe is a high-alloy austenitic stainless steel seamless pipe, commonly called 904L. It combines the American specification ASME SA312 and grade TP904L / UNS N08904 with the European material number DIN 1.4539 / X1NiCrMoCu25-20-5. It is used where high corrosion resistance is required, especially in chemical processing, seawater, oil and gas, and pulp and paper applications. The “seamless” designation means it has no welded seam and is generally preferred for high-pressure, high-temperature, or highly corrosive service.

Specific situations where 904L is often chosen

1. 316L or 317L are failing or expected to fail

   • Pitting, crevice corrosion, or high corrosion rates in chlorides.

   • 904L provides a significant PREN increase.

2. Sulfuric acid and phosphoric acid service

   • The copper addition makes 904L much better than 316L or duplex in many reducing-acid environments.

   • For very severe sulfuric acid, Alloy 20 or 825 may still be better.

3. Mixed acids + chlorides

   • Chemical processing, pickling, fertilizer, phosphoric acid production.

4. Flue gas desulfurization, pulp and paper, bleach plants

   • 904L is widely used in FGD absorbers, piping, and pulp/paper bleaching.

5. Seawater and marine environments

   • 904L performs well in many seawater applications, but for higher temperature, higher velocity, or severe crevice conditions, 2205, 2507, or 6Mo may be better.

6. Oil and gas / chemical piping

   • Where moderate strength, good corrosion resistance, and weldability are needed.

   • For sour service or high-pressure seawater, duplex/super duplex may be preferred.

Equivalent Grades of ASME SA312 UNS N08904 / TP904L Stainless Steel Pipe DIN 1.4539 Seamless Pipe

 
 
Chemical Composition % of ASME SA312 UNS N08904 / TP904L Stainless Steel Pipe DIN 1.4539 Seamless Pipe

 
Mechanical Properties of ASME SA312 UNS N08904 / TP904L Stainless Steel Pipe DIN 1.4539 Seamless Pipe

Applications

• Chemical and petrochemical processing equipment
• Heat exchangers, condensers, and piping systems
• Oil and gas industry
• Pulp and paper industry
• Seawater handling and marine engineering
• Flue gas desulfurization
• Food processing
• Acid production and storage
• Pollution control equipment