ASTM A335 P91 Pipe Specifications
The ASTM A335 P91 Pipe specifications, including standards, lengths and surface finish, are listed in the table below.
| Parameter | Specification |
|---|---|
| Standards | ASTM A335 / ASME SA335 |
| Size Range | 1/2" NB to 24" NB (12.7 mm OD to 609.6 mm OD) |
| Wall Thickness | SCH 40, SCH 60, SCH 80, SCH 100, SCH 120, SCH 140, SCH 160, XXS |
| Length | Single Random, Double Random, or Cut Length (up to ~12-16 meters) |
| End Type | Plain End (PE), Bevelled End (BE), Threaded End (TE) |
| Surface Finish | Black Painted, Varnished, Anti-corrosion Oil, Shot Blasted |
| Form | Seamless |
ASTM A335 P91 Pipe Sizes & Dimensions
The available ASTM A335 P91 pipe sizes and dimensions are listed in the table given below.
| Parameter | Range |
|---|---|
| Nominal Pipe Size | 1/2" NB to 24" NB (DN15 to DN600) |
| Outer Diameter | 21.3 mm to 610 mm |
| Wall Thickness | 3 mm to 60+ mm |
| Schedule | 40, 80, 120, 160, STD, XS, XXS |
| Length | Single Random (5 to 7 m), Double Random (9 to 13.5 m), Cut Length |
| End Type | Beveled End (BW), Plain End (PE) |
We keep standard sizes in stock and can cut pipes to custom lengths for specific projects.
Dimensional Tolerances for ASTM A335 P91 Pipe
The table given below explains dimensional tolerances for ASTM A335 P91 pipe, including limits for outer diameter and wall thickness, as well as inspection requirements according to relevant standards.
| Parameter | Tolerance / Requirement |
|---|---|
| Applicable Standards | ASTM A335 / ASME B36.10 |
| Outer Diameter Tolerance (≤ NPS 4) | ±1.0% (Hot-Finished Seamless Pipe) |
| Outer Diameter Tolerance (≥ NPS 5) | ±0.75% (Hot-Finished Seamless Pipe) |
| Wall Thickness Tolerance | -12.5% on minimum specified thickness (no positive limit) |
| Cold-Drawn Pipe OD Tolerance | Typically ±0.5% for sizes up to NPS 4 |
| Straightness | As per ASTM A335 specification |
| Ovality | Controlled within ASTM A335 limits |
| End Squareness | As per the specification requirements |
| Dimensional Inspection | Each pipe undergoes dimensional verification before dispatch |
ASTM A335 P91 Pipe Weight Chart
Weight per metre for ASTM A335 P91 pipe depends on the outer diameter, wall thickness, and schedule. Standard weight calculation uses the formula: weight (kg/m) = (OD - WT) x WT x 0.02466, where OD and WT are in millimetres. A 6" NB Schedule 80 P91 pipe (168.3 mm OD, 10.97 mm WT) weighs approximately 42.56 kg/m. For 8" NB Schedule 120 (219.1 mm OD, 18.26 mm WT), the weight is approximately 90.44 kg/m. Contact our team for a complete weight chart covering all standard sizes and schedules.
ASTM A335 P91 Pipe Forms
ASTM A335 P91 Hot-rolled seamless pipe
ASTM A335 P91 Cold-drawn seamless pipe
ASTM A335 P91 Pipe Price
ASTM A335 P91 pipe prices are about ₹70-₹300 per kg in India and $1.00 to $9.00 per kg. It depends on OD, wall thickness, schedule, and order quantity. Final price depends on how much you order, any required certificates, the surface/end finish, alloy and raw material costs, and the agreed delivery terms (FOB/CIF/CFR).
Contact Sachiya Steel International for a competitive quotation on ASTM A335 P91 pipe in your required size and quantity.
ASTM A335 P91 Chemical Composition
The table below presents the chemical composition of ASTM A335 P91 pipe along with its symbol and proportion.
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.08 to 0.12 |
| Manganese (Mn) | 0.30 to 0.60 |
| Phosphorus (P) | 0.020 max |
| Sulphur (S) | 0.010 max |
| Silicon (Si) | 0.20 to 0.50 |
| Chromium (Cr) | 8.00 to 9.50 |
| Molybdenum (Mo) | 0.85 to 1.05 |
| Vanadium (V) | 0.18 to 0.25 |
| Nickel (Ni) | 0.40 max |
| Aluminium (Al) | 0.02 max |
| Niobium (Columbium) (Nb/Cb) | 0.06 to 0.10 |
| Titanium (Ti) | 0.01 max |
| Zirconium (Zr) | 0.01 max |
ASTM A335 P91 Mechanical Properties
The mechanical properties given in the table below apply to ASTM A335 P91 pipe in the normalised and tempered condition.
| Property | Value |
|---|---|
| Tensile Strength (min) | 585 / 85 MPa / ksi |
| Yield Strength (min, 0.2% offset) | 415 / 60 MPa / ksi |
| Elongation (min, 2" gauge) | 20% |
| Hardness (max) | 250 HBW / 25 HRC |
ASTM A335 P91 Equivalent Designations
ASTM A335 P91 pipe has equivalent designations in international standards, allowing global buyers to cross-reference specifications for procurement.
| Standard | Designation |
|---|---|
| UNS | UNS K91560 |
| EN 10216-2 | X10CrMoVNb9-1 |
| Werkstoff Nr. | 1.4903 |
| GB 5310 | 10Cr9Mo1VNb |
ASTM A335 P91 Pipe Applications
ASTM A335 P91 pipe is used in industries where piping systems operate at elevated temperatures and pressures.
Power Generation & Ultra-Supercritical Boiler Systems
P91 chrome moly pipe is used in main steam and hot reheat lines of USC boilers, steam outlet manifolds, and high-temperature connecting piping.
Oil & Gas and Petrochemical Processing
Refineries and petrochemical plants, catalytic reformer charge heaters, hydrogen generation units and high temperature reactor outlet use ASTM A335 P91 pipe.
Get the Best Price on P91 Chrome Moly Pipe
ASTM A335 P91 Type 1 vs Type 2
The table below compares the differences between ASTM A335 P91 Type 1 and Type 2 in composition, creep strength, hardness, and suitability for high-temperature applications.
| Parameter | P91 Type 1 | P91 Type 2 |
|---|---|---|
| Standard | ASTM A335 / ASME SA335 | ASTM A335 / ASME SA335 |
| Base Composition | 8.00-9.50% Cr, 0.85-1.05% Mo | Same as Type 1 |
| Trace Element Control | Standard limits | Stricter limits on Mn, S, Si, N, Sn, Sb |
| Residual Elements | Less tightly controlled | More tightly controlled for improved purity |
| Creep Performance | Good | Enhanced long-term creep strength |
| Type IV Cracking Resistance | Standard resistance | Improved resistance (especially in welded joints) |
| Hardness Requirement | Not specifically tightened beyond standard P91 limits | 190-250 HBW or 196-265 HV |
| Weld Joint Reliability | Adequate | Superior long-term weld integrity |
| Typical Applications | Conventional high-temperature service | Ultra-supercritical boilers, advanced power plants |
| Industry Preference | Widely used | Increasingly preferred for critical high-temperature applications |
ASTM A335 P91 vs P22 Pipe - Key Differences
P91 (9Cr-1Mo-V) offers significantly higher creep strength and service temperatures up to 600°C compared to P22 (2.25Cr-1Mo), which is limited to approximately 565°C. The table below summarises the key differences between these two A335 grades.
| Property | A335 P91 | A335 P22 |
|---|---|---|
| Composition | 9Cr-1Mo-V-Nb | 2.25Cr-1Mo |
| Max Service Temperature | Up to 600°C | Up to ~565°C |
| Tensile Strength (min) | 585 MPa (85 ksi) | 415 MPa (60 ksi) |
| Yield Strength (min) | 415 MPa (60 ksi) | 205 MPa (30 ksi) |
| Wall Thickness (for same pressure) | Thinner | Thicker |
| PWHT Required | Yes (730 to 770°C) | Yes (675 to 730°C) |
| Welding Complexity | Higher | Lower |
ASTM A335 P91 vs P9 Pipe
Compare ASTM A335 P9 and P91 differences in composition, alloying elements, creep strength, and suitability for high-temperature service applications.
| Parameter | ASTM A335 P9 | ASTM A335 P91 |
|---|---|---|
| Base Composition | 9Cr-1Mo | Modified 9Cr-1Mo |
| Alloying Elements | No V, Nb, or controlled N | V (0.18-0.25%), Nb (0.06-0.10%), N (0.030-0.070%) |
| Microstructure Strengthening | Limited | Carbonitride precipitates improve creep strength |
| Creep Strength | Lower | Significantly higher at elevated temperatures |
| Allowable Stress Values | Lower | Higher |
| High-Temperature Suitability | Suitable for moderate temperatures | Suitable for ultra-supercritical conditions |
| Service Temperature Range | Typically below ~540°C | Suitable for service above 540°C |
| Typical Applications | Conventional power plants, lower stress service | Advanced power plants, ultra-supercritical boilers |
| Material Selection | Used where lower strength is acceptable | Preferred for long-term high-temperature and high-pressure applications |
Heat Treatment of ASTM A335 P91 Pipe
ASTM A335 P91 pipe undergoes normalising at 1040-1080°C and tempering at 730-780°C to form a tempered martensitic structure with MX carbonitrides and M23C6 carbides for creep strength up to 600°C. Incorrect temperatures cause premature failure, so Mill Test Certificates must confirm proper normalising and tempering ranges.
Shipping & Packaging
Heavy-duty wooden boxes Packing
We strictly follow seaworthy export handling standards to protect ASTM A335 P91 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
Pipe Bundle Yard Staging
Container End-Cap Protection
Wrapped Export-Ready Bundles
We Export Worldwide
Sachiya Steel International supplies ASTM A335 P91 pipes to major industrial markets across North America, Europe, the Middle East, Asia and Africa with export-ready documentation and logistics support.
USA
Canada
Germany
UK
Italy
France
Australia
South Korea
Indonesia
Vietnam
Singapore
Malaysia
Taiwan
UAE
Saudi Arabia
Qatar
Oman
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Nigeria
Egypt