ASTM A335 P1 Alloy Steel Pipe

What is ASTM A335 P1

ASTM A335 P1 alloy pipe is a widely used alloy steel pipe for high-temperature and high-pressure applications, primarily in equipment and pipelines for industries such as oil, gas, chemical, and power. Its main components, chromium and molybdenum, significantly enhance the pipe's high-temperature resistance and corrosion resistance, making it particularly suitable for transporting supercritical and ultra-high-pressure steam.

In the oil and gas industry, ASTM A335 P1 alloy pipes are commonly used to convey high-temperature and high-pressure fluids, especially in equipment like chemical reactors, boilers, and heat exchangers. Additionally, ASTM A335 is extensively used in power plants, particularly in superheaters and reheaters of steam boilers, as these components are subjected to extreme temperature and pressure conditions during operation.

 

ASTM A335 Grade P1 Alloy Steel Pipe Chemical Compositions:

C, %	Mn, %	P, %	S, %	Si, %	Cr, %	Mo, %
0.05-0.15	0.30-0.60	0.025 max	0.025 max	0.50-1.00	1.00-1.50	0.44-0.65

 

Mechanical Properties of ASTM A335 P1 Pipes

Property	Value
Tensile Strength	55,000 psi (380 MPa) minimum
Yield Strength (0.2% offset)	30,000 psi (205 MPa) minimum
Elongation in 2″ (50mm)	30% minimum (longitudinal)
Hardness	~146 HBW max (for annealed condition, refer to specific standard)

 

ASTM A335 P1 Pipe Equivalent Materials & Standards:

Standard/Type	Equivalent Grade
ASME Pipe Standard	SA335 P1
Tube Equivalent	ASTM A213 T1 (for boiler/heat exchanger tubes)
Forging/Fitting Equivalent	ASTM A182 F1 / ASTM A234 WP1

 

Alloy Steel P1 Seamless Pipes Specification

 

‌Delivery Condition:‌

P1 shall be delivered in one of the following conditions: fully annealed, isothermally annealed, or normalized and tempered. When normalized and tempered, the minimum tempering temperature for P1 shall be 650°C.

For P1 manufactured by hot rolling or cold drawing, the manufacturer may opt for final heat treatment at 650-705°C as an alternative to the heat treatment specified in "1".

 

‌Surface Quality & Appearance:‌

Finished pipes shall have reasonable straightness.

All defects with a depth ≥12.5% of the wall thickness (S) shall be ground, repaired by welding, or removed, with no large-area repairs permitted.

Mechanical scratches, abrasions, or dents with a depth ≤10.6 mm (ensuring minimum wall thickness) are allowed; otherwise, grinding or removal is required.

Scars, cracks, folds, tears, or laminations with a depth ≤5% S are permitted; otherwise, grinding is required.

All ground areas shall maintain the minimum wall thickness, but the outer diameter may be reduced by the grinding amount.

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Hydrostatic Test:‌

Hydrostatic testing shall be performed on each pipe. With the buyer's agreement, non-destructive testing (NDT) may replace hydrostatic testing, or pipes may be delivered without hydrostatic or NDT.

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Non-Destructive Testing (NDT):‌

When required by the buyer, each pipe shall undergo NDT.

‌Ultrasonic Testing:‌ The notch depth shall not exceed 12.5% of the nominal wall thickness or 0.1 mm (whichever is greater), with the notch width not exceeding its depth.

‌Magnetic Particle Testing:‌ The notch depth shall not exceed 12.5% of the nominal wall thickness or 0.1 mm (whichever is greater), with the notch width not exceeding its depth and length not exceeding 25.4 mm.

‌Eddy Current Testing:‌ The hole diameter shall comply with the following:

D ≤ 21.3 mm: 1.0 mm

D > 21.3–42.2 mm: 1.4 mm

D > 42.2–60.3 mm: 1.8 mm

D > 60.3–141.3 mm: 2.2 mm

D > 141.3 mm: 2.7 mm

 

Packaging and shipping