ASME SA335 P9 Solid Fin Tube for Waste Heat Recovery Steam Boiler

ASTM A335 P9 Base Tube

A335 P9 Solid Fin Tube FAQ

1. What is SA335 P9 Solid Fin Tube?

• SA335 P9 is a seamless ferritic alloy-steel pipe (9% Cr, 1% Mo) with integrally welded or extruded fins to enhance heat transfer. It’s used in high-temperature/pressure environments like boilers, heaters, and heat exchangers.

2. What are the key properties of SA335 P9?

• High-temperature strength (up to ~600°C / 1112°F)
• Excellent creep & oxidation resistance
• Good weldability (pre/post-weld heat treatment required)
• Resistance to sulfidation & thermal fatigue

3. Where are SA335 P9 fin tubes commonly used?

• Power plants (superheaters, reheaters)
• Refineries (fired heaters, reformers)
• Petrochemical (ethylene crackers, heat recovery units)
• Waste heat boilers (recovering exhaust gas energy)

4. Why choose solid fins over helical/embedded fins?

• Higher durability (no risk of fin separation)
• Better heat transfer (continuous metal bond)
• Suitable for extreme thermal cycling

5. What are the ASTM/ASME standards for SA335 P9 fin tubes?

• Base Tube: ASTM SA335 P9 (seamless pipe)
• Fin Tube: Typically complies with ASME B36.10M (dimensions), ASTM A213 T9 (tube equivalent)
• Testing: Hydrostatic, ultrasonic (UT), eddy current (ET) per ASTM A450

6. How are SA335 P9 fin tubes manufactured?

• Base tube: Hot extruded/seamless cold-drawn
• Solid fins: Machined/welded integrally
• Extruded fins: Cold-formed from base metal
• Heat treatment: Normalized & tempered for stress relief

7. What are the temperature & pressure limits?

• Max temp: ~600°C (long-term), up to 650°C (short-term)
• Pressure rating: Varies by wall thickness (e.g., 1000+ psi for typical power plant applications)

8. How does SA335 P9 compare to P11, P22, or P91?

Yuhong Holding Group has more than 35 years experience for pipeline products, till now we have 3 big joint venture factories,  the total production area more than 130000 square meters, and more than 600 workers with 106 production lines give our clients excellent supporting always.   The factories already got certificates like : ABS, LR, DNV-GL, BV, KR, CCS, ASME, ISO 9001, ISO14001, ISO18001, ect.

Our factories main products as below : 
Factory 1th: Stainless steel seamless tube, Duplex steel seamless tube, Super duplex steel seamless tube, Nickel alloy steel seamless tube;

Factory 2th: Carbon steel seamless tube, Alloy steel seamless tube; Enhanced Heat Tranfer Tube, low fin tube ,U bending workshop;
Factory 3th: High frequency welding fin tube(HFW fin tube, Solid Fin tube, Studded Tube, Serrated Fin tube, Longitudinal welding fin tube), Wound fin tube(L type fin tube, LL type fin tube,  KL type fin tube), Embedded G type fin tube , Extruded fin tube,  low fin tube, U bend & 180deg. Return;

Yuhong Holding Group also has gained rich experience for project package( products contain:Pipes, Fittings, Flanges, heat exchanger, furnace, fired heater, air cooler, boiler) , YUHONG brand has marked its global presence in more than 85 countries, like, Korea, USA, Canada, Mexico, Colombia, Bolivia, Chile, Argentina, Brazil, Ecuador, Austria, New Zealand, Singapore, Malasyia, Indonesia, Thailand, Vietnam, Ukraine, Turkey,Sauid Arabia, Qatar, U.A.E,Israel,India, UK, France, Italy, Gernmany, Poland, Spain,... We have successfully implemented the orders of Cross Country Pipelines for our valuable customers. In addition, we have also developed a huge network of contacts and strategic alliances with most important manufacturers as stockists around the world.