ASTM A335 Chrome Moly Seamless Pipe

ASTM A335 Chrome Moly Pipes description

ASTM A335‌, an American standard, is specifically engineered for high-temperature service and covers core material grades including ‌P1, P2, P5, P9, P11, P12, P22, and P91‌. These alloy steel pipes are extensively utilized in ‌power generation, petrochemical, and oil refining industries‌ for conveying high-temperature, high-pressure media such as steam and hydrocarbons. Typical applications include ‌main steam piping in power plant boilers‌ and ‌superheaters in petroleum cracking furnaces‌.

 

ASTM A335 Alloy Steel Seamless Pipe specification

Outer diameter (OD): 20mm to 1000mm

Wall thickness (WT): 2mm to 100mm

Length: 6m, 12m,custom length or standard length

Material options: P5, P9, P11, P22, P91

 

A335 Material Composition & Mechanical Properties

Grade	Chemical composition(%)
	C	Si	Mn	Cr	Mo	P	S	Al	Cu	V
P5	0.05-0.15	0.50-0.80	0.30-0.60	4.50-6.00	0.90-1.20	≤ 0.025	≤ 0.025	≤ 0.030	≤ 0.25	≤ 0.10
P9	0.05-0.15	0.50-0.80	0.30-0.60	4.00-6.00	0.90-1.20	≤ 0.025	≤ 0.025	≤ 0.030	≤ 0.25	≤ 0.10
P22	0.05-0.15	0.50-0.80	0.30-0.60	2.25-2.75	0.90-1.10	≤ 0.025	≤ 0.025	≤ 0.020	≤ 0.25
P91	0.05-0.15	0.20-0.50	0.30-0.60	8.00-9.50	0.85-1.05	≤ 0.020	≤ 0.010	≤ 0.050	≤ 0.25	0.18 – 0.25

 

Grade	Mechanical properties
	Tensile Strength	Yield strength	Elongation	Hardness	Impact toughness
P5	485 – 620 MPa	≥ 205 MPa	≥ 20% (on a 50 mm long specimen)	HB : ≤ 250 HRC : ≤ 25	Meets the requirements of the Charpy impact test, usually a minimum requirement at -20°C.
P9	485 – 620 MPa	≥ 205 MPa
P22	415 – 585 MPa	≥ 205 MPa
P91	585 – 725 MPa	≥ 415 MPa

 

Quality Inspection Requirements

‌Chemical Composition Analysis‌: Detects content of major elements including chromium (Cr), molybdenum (Mo), carbon (C), manganese (Mn), silicon (Si), etc.

‌Mechanical Property Testing‌: Includes tensile strength, yield strength, elongation, reduction of area, and impact toughness.

‌Hardness Testing‌: Such as Brinell hardness (HBW) and Rockwell hardness (HRC).

‌Dimensional Tolerance Inspection‌: Measures geometric dimensions including outer diameter, wall thickness, and length.

‌Surface Quality Inspection‌: Checks for defects such as cracks, folds, and inclusions.

‌Non-Destructive Testing (NDT)‌:

Ultrasonic Testing (UT)

Magnetic Particle Testing (MT)

Liquid Penetrant Testing (PT)

‌Macrostructural Examination‌: Inspects internal defects including porosity, segregation, and cracks.

‌Microstructural Examination‌: Analyzes microstructure, grain size, and non-metallic inclusions.

‌High-Temperature Performance Testing‌:

Elevated-temperature tensile tests

Creep rupture tests (for high-temperature applications)

 

Packaging and shipping