A335 P9 Pipe Specification

Refer to the following table for the technical specifications of ASTM A335 P9 Seamless Pipe, the high-alloy solution designed for high-temperature and high-pressure service in power plants and refineries.

Property Specification / Details
Standard ASTM A335 / ASME SA335
Manufacturing Type Seamless (Hot Finished or Cold Drawn)
Size Range (NPS) 1/2" NPS to 24" NPS (Larger diameters on request)
Schedule (Wall) SCH 20, 40, STD, 80, XS, 120, 160, XXS
End Connections Bevelled, Plain, or Threaded

ASTM A335 P9 Pipe Dimensions and Sizes

Refer to the table below for a comprehensive overview of the ASTM A335 P9 pipe dimensions.

Parameter Specification Details
Size Range (NPS) 1/2" to 24" NPS
Schedule (Wall Thickness) SCH 20 through SCH XXS
Dimensional Standard ANSI / ASME B36.10
Length Options Single Random (4-7m), Double Random (7-12m), or Fixed-Length
Special Availability Larger diameters available via special order

Available Pipe Sizes

This table details the standard size availability and length configurations for P9 alloy steel pipe to help match your specific project design.

Parameter Specification / Range
Nominal Pipe Size (NPS) 1/2" NPS to 24" NPS (Larger sizes on request)
Schedules SCH 20, 40, STD, 80, XS, 120, 160, XXS
Outer Diameter (OD) 21.3 mm to 610 mm
Single Random Length (SRL) 4 Meters to 7 Meters
Double Random Length (DRL) 7 Meters to 12 Meters
Fixed Lengths Custom cut-to-length available
Standard ANSI / ASME B36.10M

Wall Thickness Tolerances

The following wall thickness tolerances apply to A335 P9 pipe per the ASTM A335 specification: These tolerances account for the manufacturing variability inherent in the seamless pipe production process. Purchasers specifying minimum wall designs should factor the minus tolerance into their pressure calculations.

Pipe Size (NPS) Wall-to-Diameter (t/D) Ratio Over Tolerance (+) Under Tolerance (-)
1/8" to 2-1/2" All Ratios 20.00% 12.50%
Above 2-1/2" 5% or less 22.50% 12.50%
Above 2-1/2" Greater than 5% 15.00% 12.50%

Outer Diameter Tolerances

These tolerances account for the potential discrepancies that may arise during the fabrication of seamless pipelines. Buyers must incorporate the negative tolerance into their pressure calculations when they establish minimum wall standards.

Size Range Tolerance
1/8" to 1-1/2" plus or minus 1/16" (0.40 mm)
Over 1-1/2" to 4" plus or minus 1/32" (0.79 mm)
Over 4" to 8" +1/16" / -1/32"
Over 8" to 12" +3/32" / -1/32"
Over 12" plus or minus 1% of specified OD

ASTM A335 P9 Pipe Price

ASTM A335 P9 pipe pricing depends on dimensions, schedule, and market rates for chromium. In India, indicative prices for 1/2" to 1.5" NPS range from ₹3,750 to ₹4,265 per unit. In the USA, the same sizes cost approximately $45 to $52.

ASTM A335 P9 Pipe Chemical Composition

The A335 P9 chemical composition defines a ferritic alloy steel balanced for oxidation resistance and high-temperature strength. The table below lists the element percentages specified under ASTM A335 / ASME SA-335 for Grade P9. The main alloying element is 8–10% chromium. Chromium oxide coatings prevent oxidation.
They prevent high-temperature gas sulfidation by protecting pipe surfaces. Molybdenum (0.90–1.10%) improves grain structure. This prevents pipe bending under high heat stress. Limiting carbon to 0.15% ensures normal and tempered weldability and durability. Silicon deoxidises steel and resists scale 0.25–1.00%.

Carbon C
0.15 max
Manganese Mn
0.30 - 0.60
Phosphorus P
0.025 max
Sulfur S
0.025 max
Silicon Si
0.25 - 1.00
Chromium Cr
8.00 - 10.00
Molybdenum Mo
0.90 - 1.10

ASTM A335 P9 Pipe Mechanical Properties

ASTM A335 P9 pipe mechanical properties confirm the grade's suitability for pressure-containing service at elevated temperatures. The following values apply per ASME SA-335.
Normalised and tempered delivery needs 205 MPa (30 ksi) yield. Minimum 30% elongation allows pipes to bend and flange without brittle fracture. The pipe is normalised at 900–955°C to refine grains and tempered at 730–790°C to ensure ductility.

415/60
MPa (ksi)
Tensile Strength (min)
205/30
MPa (ksi)
Yield Strength (min)
30
%
Elongation (min)
250
HBW
Maximum Hardness
Property Imperial Metric
Tensile Strength (min) 60 ksi 415 MPa
Yield Strength (min) 30 ksi 205 MPa
Elongation (min) 30% 30%
Maximum Hardness 250 HBW 250 HBW
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ASTM A335 P9 Pipe Equivalent Materials

ASTM A335 P9 (ASME SA-335 P9) carries equivalent designations across multiple international standards, enabling cross-border procurement without requalification. The table below maps the primary equivalents.

Standard Designation
UNS K90941
EN 10216-2 X11CrMo9-1 (W.Nr. 1.7386)
JIS G3458 STPA 26

ASTM A335 P9 Pipe Applications

ASTM A335 P9 pipe finds application across 4 primary industrial sectors where high-temperature piping integrity is non-negotiable.

Power Generation

Used in steam and reheat pipes for coal-fired plants, handling intense heat without thinning or rusting over time.

Oil & Gas Refineries

Due to its resistance to corrosion caused by sulphur in high-temperature crude oil, it is very suitable for use in furnace coils and transfer lines.

Petrochemical Processing

Handles hot gases and chemicals in ethylene crackers, lasting longer than standard steel to reduce costly plant shutdowns.

Boilers & Heat Exchangers

Used in high-heat boiler sections, allowing for thinner, lighter pipes that still safely hold extreme industrial pressures.

ASTM A335 P9 vs ASTM A335 P91 Pipe

Comprehend the primary chemical and performance differences between ASTM A335 P9 and P91 high-temperature alloy steel conduit materials.

Feature ASTM A335 P9 ASTM A335 P91
Nominal Composition 9Cr-1Mo 9Cr-1Mo-V-Nb
Alloying Additions None Vanadium (V) & Niobium (Nb)
Tensile Strength (min) 415 MPa (60 ksi) 585 MPa (85 ksi)
Yield Strength (min) 205 MPa (30 ksi) 415 MPa (60 ksi)
Temp. Ceiling (Approx.) 600°C 620°C
Creep Resistance Standard Superior (High Rupture Life)
Welding Complexity Moderate High (Strict PWHT/Preheat)
Cost Profile Economical Premium

P9 is inexpensive and straightforward for any system below 600°C. However, P91 allows for higher temperatures and thinner walls through vanadium and niobium creep resistance. This advanced grade requires much stricter welding and higher procurement prices. These features force a choice between P9's ease of use and P91's strength in extreme temperatures.

Shipping & Packaging

Main export packaging setup Heavy-duty wooden boxes Packing
Export Packaging Standard

We strictly follow seaworthy export handling standards to protect ASTM A335 P9 Pipe from transit damage, moisture ingress, and surface contamination during long-distance dispatch.

  • Heavy-duty wooden boxes with moisture barrier lining
  • HDPE stretch film wrapping on all bundles
  • Plastic end caps on threaded and plain-end pipes
  • Silica gel desiccants to minimize moisture exposure
  • ISPM-15 fumigated wooden packaging for export
shipping preparation Pipe Bundle Yard Staging
Shipping packaging Container End-Cap Protection
Shipping stock Wrapped Export-Ready Bundles

We Export Worldwide

Sachiya Steel International supplies Alloy steel products to major industrial markets across North America, Europe, the Middle East, Asia and Africa with export-ready documentation and logistics support.

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Frequently Asked Questions

What is ASTM A335 P9 Pipe?+
ASTM A335 P9 pipe is a seamless ferritic alloy steel pipe with 8.00 to 10.00% chromium and 0.90 to 1.10% molybdenum, manufactured under the ASTM A335 / ASME SA-335 specification. Suitable for elevated-temperature service environments up to approximately 600°C in power plants, refineries, and petrochemical facilities. The grade is commonly referred to as 9Cr-1Mo chrome moly pipe.
What is P9 Pipe material equivalent to?+
P9 pipe material is equivalent to EN 10216-2 X11CrMo9-1 (W.Nr. 1.7386) in Europe and JIS G3458 STPA 26 in Japan. The ASME equivalent designation is SA-335 P9. Companion specifications for the same 9Cr-1Mo alloy include ASTM A182 F9 for forgings, ASTM A234 WP9 for wrought fittings, and ASTM A213 T9 for seamless tubes.
What is the difference between P9 and P91 Pipe?+
P9 (9Cr-1Mo) and P91 (9Cr-1Mo-V-Nb) share similar base chromium and molybdenum content, but P91 contains vanadium and niobium. These changes increase P91's minimum tensile strength to 585 MPa from 415 MPa for P9. P91 allows thinner walls and supports temperatures up to 620°C. It costs more and requires longer PWHT cycles and stricter welding conditions.
What welding rod is used for ASTM A335 P9 Pipe?+
ASTM A335 P9 pipe is typically welded using AWS E/ER 505 (9Cr-1Mo) filler metals. Preheat the joint to 200 to 250°C before striking the arc. Post-weld heat treatment is mandatory after all welds on P9 pipe. Interpass temperature must be controlled per the approved welding procedure specification to prevent hydrogen-induced cracking in the heat-affected zone.
What are the standard dimensions of ASTM A335 P9 Pipe?+
After the normalisation and tempering process, the hardness can reach upto 250 HBW. Each heat batch is tested for hardness to meet specifications. This restriction is essential for NACE MR0175 sour service applications. Safety depends on this level since hardness promotes sulphide stress cracking.
What is the maximum hardness of ASTM A335 P9 Pipe?+
By normalising and tempering the steel, we hit that 250 HBW hardness target every time. It's non-negotiable. For anyone working in NACE MR0175 sour service, this limit is the only thing standing between a stable system and a catastrophic sulfide stress crack. We test every single heat batch without exception.
What is the microstructure of ASTM A335 P9 Pipe?+
After normalising at 900 to 955°C and tempering at 730 to 790°C, ASTM A335 P9 pipe exhibits a tempered martensite and bainite microstructure. This dual-phase structure provides the balance of creep resistance and toughness required for long-term service at elevated temperatures. The fine distribution of carbide precipitates within the tempered matrix contributes to the grade's resistance against creep deformation.
What is the price of ASTM A335 P9 Pipe?+
Pricing for ASTM A335 P9 pipe varies by outer diameter, wall thickness, length, quantity, and mill origin. Indicative prices for common sizes (1/2" to 1.5" NPS) range from INR 3,750 to INR 4,265 per unit. Final cost also depends on supplementary requirements such as NACE compliance, IBR certification, and surface finish. Contact Sachiya Steel International for a current quotation tailored to your project specifications.

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