ASTM A335 P22 seamless steel pipes must comply with TSG D7002–Pressure Piping Component Type Test Regulations, ensuring safety and performance in high-temperature and high-pressure environments.
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Specifications of ASTM A335 P22 Seamless Steel Pipe
Outside Diameter: 21.3 mm–762 mm
Wall Thickness: 2.0 mm–140 mm
This wide specification range makes ASTM A335 P22 suitable for various industrial piping applications, including boilers, power stations, and petrochemical systems.
Chemical Composition (% by weight)
ASTM A335 P22 alloy steel pipe contains precise elements that enhance high-temperature strength and corrosion resistance:
Carbon (C): 0.05–0.15
Manganese (Mn): 0.30–0.60
Phosphorus (P):≤0.025
Sulfur (S):≤0.025
Silicon (Si):≤0.50
Chromium (Cr): 1.90–2.60
Molybdenum (Mo): 0.87–1.13
Nickel (Ni):≤0.50
Mechanical Properties
ASTM A335 P22 seamless steel pipes are designed to withstand elevated temperature and pressure conditions:
Tensile Strength:≥415 MPa
Yield Strength:≥205 MPa
Elongation:≥30%
Brinell Hardness (HBW):≤163
These properties ensure excellent creep resistance and ductility, essential for long-term service at high temperatures.
Manufacturing Methods & Delivery Condition
ASTM A335 P22 pipes are manufactured via:
Cold Drawing
Hot Rolling
Hot Expansion
Delivery condition: All pipes undergo heat treatment to meet metallurgical and mechanical requirements for high-temperature service.
Surface Quality & Appearance Standards
Defect Inspection & Evaluation
Steel pipe manufacturers must identify and evaluate visible surface defects to ensure compliance. Not all surface imperfections require measurement, but a sufficient quantity must be assessed to guarantee uniform quality.
Harmful Defect Definition:
Any surface flaw with a depth exceeding 12.5% of the nominal wall thickness, or any flaw that compromises the minimum required wall thickness, is considered harmful.
Permitted Defect Treatments
Grinding
Defects may be removed with a grinding wheel if the remaining wall thickness stays within standard limits.
Grinding must create a smooth, tapered transition without sharp reductions in wall thickness.
Pipe Cutting
Defective segments within allowable length tolerance may be cut and removed.
Defect Removal Criteria
The following defects must be removed if they exceed 1.6 mm in depth or affect visual quality:
Mechanical scratches
Pits and gouges
Rope marks, rail scratches, roller marks, steel ball impressions, and mold scars
Acceptable Appearance Standards
Even if surface flaws meet dimensional standards, pipes may be rejected if defects are large-area concentrated and aesthetically unacceptable. Final decisions can be negotiated between the manufacturer and the buyer.
Wall Thickness Verification
Wall thickness at the grinding area must not fall below the allowable limit.
Measurements should be conducted using a mechanical caliper or calibrated non-destructive testing device.
In case of disputes, caliper measurements take precedence.
Summary
ASTM A335 P22 seamless alloy steel pipe is a high-performance material designed for high-temperature pressure systems, such as boilers, heat exchangers, and petrochemical plants. It offers excellent strength, creep resistance, and dimensional precision, backed by strict surface and quality standards. Its optimized chemistry and controlled production processes make it a reliable choice for demanding thermal and mechanical applications.