Chrome Moly Pipe (ASTM A335) | Alloy Steel Seamless Pipes Supplier | P5 P9 P11 P22 Grades
Chrome moly pipe (chromium molybdenum alloy steel pipe) is a high-strength ASTM A335 steel pipe designed for extreme high-temperature and high-pressure applications in industries such as oil & gas, petrochemical processing, and power
generation. It contains chromium (Cr) and molybdenum (Mo) as key alloying elements, which significantly improve oxidation resistance, creep strength, and long-term mechanical stability under elevated temperatures.
Compared with standard carbon steel pipe, chrome moly pipe offers superior performance in severe operating environments, making it the preferred material for critical systems such as refinery pipelines, boiler tubes, superheaters, and high-pressure steam lines. Common grades include P5, P9, P11, P22, and P91, each engineered for different temperature and pressure requirements.
As a professional chrome moly pipe supplier, we provide full-range ASTM A335 alloy steel seamless pipes with strict quality control, third-party inspection, and global export capability for EPC and industrial projects worldwide.
What is Chrome Moly Pipe?
Chrome moly pipe (short for chromium molybdenum alloy steel pipe) is a type of high-performance seamless steel pipe made with chromium (Cr) and molybdenum (Mo) as key alloying elements. It is mainly produced under standards such as ASTM A335 / ASME SA335, and is designed for high-temperature and high-pressure industrial environments.
These pipes are widely used in industries where ordinary carbon steel cannot perform reliably, especially in oil & gas refineries, power generation plants, petrochemical systems, and boiler systems.
-
![ASTM A691 1-1/4CR Pipe]()
ASTM A691 1-1/4CR PipeStandard and Grades: ASTM A691 1-1/4CR, 2-1/4CR, 2-1/4CR, 3CR, 5CR, 9CR, 91. Material types: Chrome Moly Welded Pipe. Manufacturing types: EFW Electric-Fusion-Welded. Sizes: 16” to 60”. Wall -
![ASTM A335 P91 Pipe]()
ASTM A335 P91 PipeStandard and Grades: ASTM A335 / ASME SA335 Grade P91. Material types: Chrome Moly Alloy. Manufacturing types: Seamless hot rolled. Sizes: 1/2” to 24” DN25 to DN600. Wall thickness: SCH 40, SCH STD, -
![ASTM A335 P5 Pipe]()
ASTM A335 P5 PipeChrome Moly Pipe: ASTM A335 / ASME SA335 Grade P5. Fabrication type: Seamless Steel Pipe. Chrome content 4.00 % to 6.00%, Molybdenum 0.45 to 0.65%.. Supply Range: 1/2” to 36” DN25 to DN900. Wall -
![ASTM A335 P22 Pipe (2.25Cr-1Mo Chrome Moly Steel) – Size, Specification, Price, SCH40 SCH80 Supplier]()
ASTM A335 P22 Pipe (2.25Cr-1Mo Chrome Moly Steel) – Size, Specification, Price, SCH40 S...ASTM A335 P22 / ASME SA335 Grade P22. Chrome Moly Alloy Pipe in Seamless. Seamless pipe by hot rolled or cold drawn with proper heatreatment. Sizes: 1/2” to 24”. Wall thickness: SCH 40, SCH STD, SCH -
![ASTM A335 P11 Pipe | Chrome Moly Alloy Steel Seamless Pipe Supplier | SA335 P11]()
ASTM A335 P11 Pipe | Chrome Moly Alloy Steel Seamless Pipe Supplier | SA335 P11ASTM A335 / ASME SA335 Grade P11. Chrome Moly Alloy. Seamless pipe by hot rolled or cold drawn. Sizes: 1/2” to 24”. Wall thickness: SCH 40, SCH STD, SCH 80, SCH XS, SCH 160. Length: 6 meters, 12 -
![ASTM A335 P9 Pipe | Chrome Moly Alloy Steel Pipe Supplier | High Temperature Seamless Pipe]()
ASTM A335 P9 Pipe | Chrome Moly Alloy Steel Pipe Supplier | High Temperature Seamless PipeProduct Name: ASTM A335 P9 Pipe. Also Known As: Chrome Moly Pipe / Alloy Steel Pipe P9. Type: Seamless Ferritic Alloy Steel Pipe. Standard: ASTM A335 / ASME SA335. Applications: Refinery /
Chrome Moly Pipe Grades (P Grades Overview)
| Grade | Material | Max Temp | Application |
|---|---|---|---|
| P5 | 5Cr-0.5Mo | ~600°C | Refinery |
| P9 | 9Cr-1Mo | ~620°C | Steam lines |
| P11 | 1.25Cr-0.5Mo | ~600°C | Boilers |
| P22 | 2.25Cr-1Mo | ~600°C | Power plants |
| P91 | 9Cr-1Mo-V | ~650°C | Ultra-supercritical |
Chrome Moly Pipe Size Range (ASTM A335) – Full Size Chart
| NPS (Inch) | DN (mm) | Outside Diameter (mm) | SCH 10 WT (mm) | SCH 40 WT (mm) | SCH 80 WT (mm) | SCH 160 WT (mm) | XXS WT (mm) |
|---|---|---|---|---|---|---|---|
| 1/8" | DN6 | 10.3 | 1.24 | 1.73 | 2.41 | 3.02 | 3.02 |
| 1/4" | DN8 | 13.7 | 1.65 | 2.24 | 3.02 | 3.56 | 3.56 |
| 3/8" | DN10 | 17.1 | 1.65 | 2.31 | 3.20 | 4.01 | 4.01 |
| 1/2" | DN15 | 21.3 | 2.11 | 2.77 | 3.73 | 4.78 | 7.47 |
| 3/4" | DN20 | 26.7 | 2.11 | 2.87 | 3.91 | 5.56 | 7.82 |
| 1" | DN25 | 33.4 | 2.77 | 3.38 | 4.55 | 6.35 | 9.09 |
| 1 1/4" | DN32 | 42.2 | 2.77 | 3.56 | 4.85 | 6.35 | 9.70 |
| 1 1/2" | DN40 | 48.3 | 2.77 | 3.68 | 5.08 | 7.14 | 10.15 |
| 2" | DN50 | 60.3 | 2.77 | 3.91 | 5.54 | 8.74 | 11.07 |
| 2 1/2" | DN65 | 73.0 | 3.05 | 5.16 | 7.01 | 9.53 | 14.02 |
| 3" | DN80 | 88.9 | 3.05 | 5.49 | 7.62 | 11.13 | 15.24 |
| 3 1/2" | DN90 | 101.6 | 3.05 | 5.74 | 8.08 | 12.70 | 15.24 |
| 4" | DN100 | 114.3 | 3.05 | 6.02 | 8.56 | 13.49 | 17.12 |
| 5" | DN125 | 141.3 | 3.40 | 6.55 | 9.53 | 15.88 | 19.05 |
| 6" | DN150 | 168.3 | 3.40 | 7.11 | 10.97 | 18.26 | 21.95 |
| 8" | DN200 | 219.1 | 3.76 | 8.18 | 12.70 | 20.62 | 23.01 |
| 10" | DN250 | 273.0 | 4.19 | 9.27 | 15.09 | 25.40 | 28.58 |
| 12" | DN300 | 323.9 | 4.57 | 10.31 | 17.48 | 28.58 | 33.32 |
| 14" | DN350 | 355.6 | 6.35 | 11.13 | 19.05 | 31.75 | 35.71 |
| 16" | DN400 | 406.4 | 6.35 | 12.70 | 21.44 | 36.53 | 40.49 |
| 18" | DN450 | 457.2 | 6.35 | 14.27 | 23.83 | 39.67 | 45.24 |
| 20" | DN500 | 508.0 | 6.35 | 15.09 | 26.19 | 44.45 | 50.01 |
| 24" | DN600 | 609.6 | 6.35 | 17.48 | 30.96 | 52.37 | 59.54 |
Chrome Moly Pipe Weight Chart
| NPS (Inch) | OD (mm) | SCH 10 | SCH 40 | SCH 80 | SCH 160 | XXS |
|---|---|---|---|---|---|---|
| 1/2" | 21.3 | 0.85 | 1.27 | 1.80 | 2.70 | 4.50 |
| 3/4" | 26.7 | 1.14 | 1.69 | 2.50 | 3.50 | 5.80 |
| 1" | 33.4 | 1.70 | 2.50 | 3.80 | 5.40 | 7.90 |
| 1 1/4" | 42.2 | 2.20 | 3.39 | 5.10 | 7.30 | 10.50 |
| 1 1/2" | 48.3 | 2.80 | 4.05 | 6.20 | 8.90 | 12.80 |
| 2" | 60.3 | 3.60 | 5.40 | 8.40 | 12.20 | 17.10 |
| 2 1/2" | 73.0 | 5.30 | 8.00 | 12.10 | 17.60 | 24.50 |
| 3" | 88.9 | 7.30 | 11.30 | 17.00 | 25.10 | 34.80 |
| 4" | 114.3 | 10.80 | 16.10 | 24.70 | 36.80 | 50.90 |
| 5" | 141.3 | 15.30 | 23.40 | 36.10 | 54.20 | 74.30 |
| 6" | 168.3 | 20.30 | 31.50 | 49.00 | 74.00 | 101.50 |
| 8" | 219.1 | 31.30 | 49.60 | 79.30 | 119.00 | 162.00 |
| 10" | 273.0 | 43.40 | 64.10 | 102.00 | 155.00 | 210.00 |
| 12" | 323.9 | 55.80 | 83.00 | 131.00 | 201.00 | 270.00 |
| 14" | 355.6 | 70.00 | 98.00 | 158.00 | 242.00 | 320.00 |
| 16" | 406.4 | 84.00 | 124.00 | 197.00 | 305.00 | 410.00 |
| 18" | 457.2 | 100.00 | 150.00 | 238.00 | 360.00 | 485.00 |
| 20" | 508.0 | 122.00 | 180.00 | 287.00 | 430.00 | 580.00 |
| 24" | 609.6 | 165.00 | 245.00 | 390.00 | 590.00 | 790.00 |
Chrome Moly Pipe vs Carbon Steel Pipe
| Aspect | Chrome Moly Pipe (ASTM A335) | Carbon Steel Pipe |
|---|---|---|
| Material Type | Alloy steel (Cr-Mo) | Carbon steel |
| Main Composition | Fe + Cr + Mo | Fe + C |
| High Temperature Performance | ⭐⭐⭐⭐⭐ Excellent, stable in long-term high heat service | ⭐⭐ Limited, strength decreases at high temperature |
| High Pressure Performance | ⭐⭐⭐⭐⭐ Suitable for high & ultra-high pressure systems | ⭐⭐⭐ Suitable for low to medium pressure |
| Creep Resistance | ⭐⭐⭐⭐⭐ Excellent (key advantage) | ⭐ Poor |
| Oxidation Resistance | ⭐⭐⭐⭐ Good (due to chromium content) | ⭐⭐ Weak, prone to oxidation and scaling |
| Operating Temperature Range | High temperature service (≈450–600°C depending on grade) | Low to medium temperature (<400°C) |
| Pressure Application Level | High-pressure / critical systems | Low to medium pressure systems |
| Typical Applications | Power plants, boilers, superheaters, refineries, petrochemical plants | Water pipelines, structural piping, general industrial use |
| Welding Requirements | Requires preheating + PWHT (Post Weld Heat Treatment) | Easy to weld |
| Service Life | Long service life in harsh environments | Medium to short in demanding conditions |
| Cost | Higher 💰💰💰 | Lower 💰 |
| Standards | ASTM A335 / ASME SA335 | ASTM A53 / ASTM A106 / API 5L |
Chrome Moly Pipe (Alloy Steel Pipe) → Designed for high-temperature, high-pressure, and critical industrial applications
Carbon Steel Pipe → Suitable for general-purpose, low-cost, and non-critical piping systems
Applications of Chrome Moly Pipe
⚡ 1. Power Generation Industry (Power Plants)
Chrome moly pipes are extensively used in thermal and nuclear power plants.
Boiler superheater tubes
Reheater tubes
Main steam pipelines
High-pressure steam distribution systems
Feedwater heating systems
👉 Key advantage: Excellent creep resistance under continuous high-temperature steam.
🔥 2. Boiler & Heat Exchanger Systems
Widely applied in industrial boilers and thermal energy transfer equipment.
Industrial boiler tubing
Heat exchanger tubes
Economizer systems
Steam generator piping
Furnace heat recovery systems
👉 Key advantage: High oxidation resistance and long service life in thermal cycling environments.
🛢 3. Oil & Gas Refinery Industry
Used in upstream and downstream petroleum refining operations.
Refinery process piping systems
High-temperature hydrocarbon transport lines
Catalytic cracking units
Desulfurization units
High-pressure process pipelines
👉 Key advantage: Stable performance under corrosive and high-temperature conditions.
🧪 4. Petrochemical Industry
Essential material for chemical processing and high-temperature reaction systems.
Chemical reactor piping
Cracking furnace systems
Process heating pipelines
High-pressure chemical transfer lines
Industrial processing units
👉 Key advantage: Resistance to thermal stress and chemical exposure.
⚙ 5. Industrial Furnace & Thermal Systems
Used in heavy-duty thermal processing environments.
Industrial furnaces
Kiln piping systems
Heat treatment equipment
Thermal processing plants
Energy recovery systems
👉 Key advantage: Maintains strength and stability under extreme heat.
🏭 6. High-Pressure Steam & Energy Systems
Critical for energy transportation and pressure systems.
High-pressure steam pipelines
Power plant auxiliary piping systems
Industrial steam distribution networks
Pressure vessel connection piping
👉 Key advantage: Safe long-term operation under high pressure and temperature.
Inspection & Quality Control of Chrome Moly Pipe (ASTM A335)
Chrome Moly Pipes (ASTM A335 / ASME SA335) are used in high-temperature and high-pressure critical systems, so strict inspection and quality control (QC) is essential to ensure safety, reliability, and long service life.
🧪 1. Raw Material Inspection
Before production, all raw materials are strictly checked:
Chemical composition verification (Cr, Mo content control)
Material grade confirmation (P5, P9, P11, P22, P91)
Surface quality inspection
Heat number traceability verification
👉 Ensures compliance with ASTM A335 requirements from the beginning.
🔥 2. Chemical Composition Testing
Each batch is tested to confirm alloy content:
Carbon (C), Chromium (Cr), Molybdenum (Mo)
Manganese (Mn), Silicon (Si), Sulfur (S), Phosphorus (P)
Spectrochemical analysis (SPECTRO / OES testing)
👉 Guarantees correct alloy balance for high-temperature performance.
⚙ 3. Mechanical Property Testing
To ensure strength and durability:
Tensile strength test
Yield strength test
Elongation test
Hardness test (as required)
👉 Ensures pipes meet ASTM A335 mechanical standards.
🔥 4. Heat Treatment Control
Heat treatment is critical for chrome moly pipes:
Normalizing
Tempering
Annealing (depending on grade)
👉 Ensures proper microstructure for creep resistance and stability.
📡 5. Non-Destructive Testing (NDT)
100% or required percentage inspection:
Ultrasonic Testing (UT) – internal defects
Eddy Current Testing (ECT) – surface defects
Radiographic Testing (RT) – weld inspection (if applicable)
Magnetic Particle Testing (MT)
👉 Ensures defect-free seamless pipe structure.
💧 6. Hydrostatic Test
Each pipe is pressure tested:
High-pressure water test
Leak detection
Pressure holding verification
👉 Ensures safety under real operating conditions.
📏 7. Dimensional Inspection
Strict dimensional control:
Outer diameter (OD)
Wall thickness (WT)
Length tolerance
Straightness
Ovality
👉 Ensures compatibility with piping systems and fittings.
📦 8. Final Visual & Surface Inspection
Before shipment:
Surface defects check (cracks, rust, scratches)
End finishing inspection (beveled/plain ends)
Marking verification (grade, heat number, size)
Packaging inspection
📄 9. Certification & Documentation
Each shipment includes full documentation:
Mill Test Certificate (MTC EN 10204 3.1 / 3.2)
Chemical & mechanical test reports
Heat number traceability report
Inspection reports (internal / third-party)
Optional third-party inspection (SGS / BV / TUV)
Xi'an Dongmeng Group Co., Ltd. is one of the leading chrome moly pipe (astm a335) manufacturers and suppliers in China. We warmly welcome you to buy or wholesale cheap chrome moly pipe (astm a335) in stock here from our factory. All customized products are with high quality and competitive price. For free sample, contact us now.
ASTM A335 P5 Pipe, ASTM A335 P22 Pipe, ASTM A691 1 1 4CR PipePopular Products
