ASTM A335 P11 Chrome-Moly Seamless Tube with High-Temperature and Creep Resistance for Heat Exchangers

Yuhong Group Co., Ltd. supplies critical components for high-temperature service, including heat exchanger tubes, fin tubes, furnace tubes, stainless steel seamless tubes, nickel alloy tubes, copper alloy tubes, heat exchanger tube bundles, and heat exchanger tubesheets. We also design and manufacture complete shell & tube heat exchangers, pressure vessels, and air coolers. Shown in the attached photograph is our ASTM A335 P11 alloy steel seamless tube - a chrome-moly grade widely used in furnaces, fired heaters, reformers, and high-temperature heat exchangers.

The ASTM A335 P11 tube is a seamless ferritic alloy steel tube manufactured to ASME Specification A335/A335M. Grade P11 has a nominal composition of 1.25% chromium and 0.5% molybdenum (1¼Cr-½Mo). This chrome-moly alloy offers:

• Excellent creep resistance at elevated temperatures (up to approximately 550°C / 1020°F)
• Oxidation resistance superior to plain carbon steel
• Good hydrogen attack resistance - suitable for hydrogen service
• High thermal fatigue strength - withstands repeated heating and cooling cycles

These properties make P11 the preferred material for furnace radiant tubes, convection section tubes, fired heater coils, transfer lines, and high-temperature heat exchanger tubes in refineries, petrochemical plants, and power stations.

• Seamless construction: No longitudinal weld - eliminates a potential failure point in high-temperature, high-pressure service.
• Full heat treatment: Tubes are supplied in the normalized and tempered (N &T) condition - optimal microstructure for creep resistance.
• Dimensional accuracy: Outside diameter, wall thickness, and straightness per ASTM A335 tolerances.
• Testing & certification: Each tube lot includes Mill Test Certificates (MTC) showing chemical composition, tensile strength, hardness, and flattening/flaring test results.
• Optional NDE: Ultrasonic testing (UT), eddy current testing, or hydrostatic testing available per customer specification.

• Operating temperature 450-550 °C (840-1020°F)
• Hydrogen partial pressure significant (e.g., reformer, hydrotreater)
• Need better oxidation resistance than carbon steel
• Budget does not justify higher grades like P22 or P9

• Not suitable for >550°C continuous service - upgrade to P22 or P9
• Requires preheating before welding and post-weld heat treatment (PWHT) - do not weld cold
• May still suffer excessive scaling in highly oxidizing atmospheres above 500°C

• Exact material match - same grade and heat treatment as original specification.
• Same outside diameter and wall thickness - direct replacement without modifying tube supports or headers.
• Full traceability - each tube is marked with heat number and certified to ASME A335.
• Fast delivery - we stock common sizes (OD 1/2″ to 24″, wall schedules 40 to 160) and can cut to length.

Need furnace tube replacements or related components? We supply:

• Furnace tubes (ASTM A335 P11) - straight lengths, cut-to-size, ends prepared (beveled) for welding.
• Fin tubes - P11 base tube with carbon or alloy steel fins for convection section upgrades.
• Heat exchanger tubes - P11 seamless tube for high-temperature shell & tube heat exchangers.
• Return bends / fittings - ASTM A234 WP11 fittings for coil assembly.
• Tube supports / guides - high-temperature alloy castings or fabrications.

To supply ASTM A335 P11 tubes for your furnace or fired heater project, send the following to jimmy@steelseamlesspipe.com:

• Outside diameter (OD) and wall thickness (or schedule)
• Total length required (cut-to-length or random lengths)
• Quantity (number of tubes or total linear meters)
• Any special testing requirements (UT, hydro, PMI)
• Delivery destination and required schedule

We will respond with a technical datasheet, material certification sample, and competitive price - typically within 24 hours.