ASTM A335 Seamless ferritic alloy steel pipe for high temperature service

ASTM A335 specification covers seamless ferritic alloy-steel pipe for high-temperature service. The pipe shall be suitable for bending, flanging, and similar forming operations, and for fusion welding. Grade P2 and P12 steel pipes shall be made by coarse-grain melting practice. The steel material shall conform to chemical composition, tensile property, and hardness requirements. Each length of pipe shall be subjected to the hydrostatic test. Also, each pipe shall be examined by a non-destructive examination method in accordance to the required practices. The range of pipe sizes that may be examined by each method shall be subjected to the limitations in the scope of the respective practices. The different mechanical test requirements for pipes, namely, transverse or longitudinal tension test, flattening test, and hardness or bend test are presented.

ASTM A335 Seamless Alloy-Steel Pipe
Scope: This specification covers nominal wall and minimum wall seamless chrome moly seamless pipes for the power generation and petrochemical industries. ASTM A335 Seamless Steel Pipe ordered to this specification shall be suitable for fusion welding, bending, flanging (vanstoning), and similar forming operations. With chrome and moly element added, ASTM A335 offers good tensile strength, fine resistance to high temperature and corrosion.

ASTM A335 Grades
It covers steel grades from P1 to P5, P9, P11, P12, P91. Grades P11/P22 and P91/92 are commonly used in power stations, while A335 grade P5 and P9 are mostly used for application in the petrochemical industry.
ASTM A335 Seamless Steel Pipe Specifications:
Name: ASTM A335 alloy steel pipe
Diameter:16-1016mm
Thickness: 2---120mm
Steel grade: P1 P2 P5 P9 P11 P12 P22
Surface: oiled, black painted to prevent rust
United Steel Industry Co.,Ltd supplies a full range of the following ASTM A335 Seamless Alloy-Steel Pipe, click to check View of ASTM A335 Dimensional Table.
Applications of ASTM A335 Pipes
The most common use of grades P11, P22, and P91 is in the power industry and petro-chemical plants, Grades P5 and P9 are commonly used in refineries.
ASTM A335 is often called as chrome moly pipe because of the chemical contain of Molybdenum (Mo) and Chromium (Cr). Molybdenum increases the strength of steel and Chromium (or chrome) is the essential constituent of stainless steel.
The composition chrome moly alloy steel pipe make it ideal for use in power plants, refineries, petro chemical plants, and oil field services where fluids and gases are transported at extremely high temperatures and pressures.
Chrome moly pipe under ASTM & ASME specification A/SA 335 P1, P2, P11, P12, P15, P22, P91, P92, P122 are used for power industries whereas ASTM/ASME A/SA 335 P5, P9 are used for petrochemical industries
Strong resistance to rupturing at high temperatures and high pressures
May be used for Hydrogen Sulfide Corrosion Services
Resistant to cracking from hydrogen attack and embrittlement
Resistant to hot sulfide corrosion cracking
Can be used for NACE Applications where sour environments are under high temp and pressure
Can be used in NACE-MRO 175 Sour Service
Ideal for creep rupture applications
Can handle high temperatures with very low elasticity
Certitifcation: Chrome Moly pipe are certified as PER DIN 50049 3.1, EN 10204 3.1/3.2 and NACE MR-0175 & NACE MR-0103
Piping Component Specifications:
Flanges and forged fittings – A/SA 182 F1, F2, F5, F9, F11, F12, F15, F22, F91, F92, F122 Wrought
Butt-weld Pipe Fittings – A/SA 234 P1, P2, P5, P9, P11, P12, P15, P22, P91, P92, P122
Chemical Composition
These pipe bear high resistance to rupture at high temperature and pressures. With hydrogen crack resistance and sulfide stress corrosion cracking chrome moly pipe are highly preferred over Carbon pipe.

Tensile Requirements

Note: P91 shall not have a hardness not exceeding 250 HB/265 HV [25HRC].
Mechanical Properties

A335 is often called chrome moly pipe because of the chemical makeup of Molybdenum (Mo) and Chromium (Cr). Molybdenum increases the strength of steel as well as the elastic limit, resistance to wear, impact qualities, and hardenability. Moly increases the resistance to softening, restrains grain growth and makes chromium steel less susceptible to embrittlement. Moly is the most effective single additive that increases high temperature creep strength.
It also enhances the corrosion resistance of steel, and inhibits pitting. Chromium (or chrome) is the essential constituent of stainless steel. Any steel with 12% or more Chrome is considered stainless. Chrome is virtually irreplaceable in resisting oxidation at elevated temperatures. Chrome raises the tensile, yield, and hardness at room temperatures. The composition chrome moly alloy steel pipe make it ideal for use in power plants, refineries, petro chemical plants, and oil field services where fluids and gases are transported at extremely high temperatures and pressures.
Heat Treatment Requirements

Mechanical Tests Specified
Transverse or Longitudinal Tension Test and Flattening Test, Hardness Test, or Bend Test
For material heat treated in a batch-type furnace, tests shall be made on 5% of the pipe from each treated lot. For small lots, at least one pipe shall be tested.
For material heat treated by the continuous process, tests shall be made on a sufficient number of pipe to constitute 5% of the lot, but in no case less than 2 pipe.
Notes for Hardness Test:
P91 shall not have a hardness not exceeding 250 HB/265 HV [25HRC].
Notes for Bend Test:
For pipe whose diameter exceeds NPS 25 and whose diameter to wall thickness ratio is 7.0 or less shall be subjected to the bend test instead of the flattening test.
Other pipe whose diameter equals or exceeds NPS 10 may be given the bend test in place of the flattening test subject to the approval of the purchaser.
The bend test specimens shall be bent at room temperature through 180 without cracking on the outside of the bent portion.
Hydrostatic Test
The inside diameter of the bend shall be 1 inch [25 mm].
Each length of pipe shall be Hydro tested, at option of manufacture nondestructive electric testing can be used.