ASTM A335 / A335M – 15a: Standard Specification for Seamless Ferritic Alloy Steel Pipe for High-Temperature Service

ASTM A335 / A335M – 15a

Standard Specification for Seamless Ferritic Alloy Steel Pipe for High-Temperature Service

1. Scope

1.1 This specification2 covers nominal wall and minimum wall seamless ferritic alloy-steel pipe intended for high-temperature service. Pipe ordered to this specification shall be suitable for bending, flanging (vanstoning), and similar forming operations, and for fusion welding. Selection will depend upon design, service conditions, mechanical properties, and high-temperature characteristics.

1.2 Several grades of ferritic steels (see Note 1) are covered. Their compositions are given in Table 1.

NOTE 1: Ferritic steels in this specification are defined as low- and intermediate-alloy steels containing up to and including 10 % chromium.

(A) New designation established in accordance with Practice E527 and SAE J1086, Practice for Numbering Metals and Alloys (UNS).
(B) Grade P 5c shall have a titanium content of not less than 4 times the carbon content and not more than 0.70 %; or a columbium content of 8 to 10 times the carbon content.
(C) Alternatively, in lieu of this ratio minimum, the material shall have a minimum hardness of 275 HV in the hardened condition, defined as after austenitizing and cooling to room temperature but prior to tempering. Hardness testing shall be performed at mid-thickness of the product. Hardness test frequency shall be two samples of product per heat treatment lot and the hardness testing results shall be reported on the material test report.

1.3 Supplementary requirements (S1 to S8) of an optional nature are provided. Supplementary requirements S1 through S6 call for additional tests to be made, and when desired, shall be so stated in the order together with the number of such tests required.

1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order.

NOTE 2: The dimensionless designator NPS (nominal pipe size) has been substituted in this standard for such traditional terms as “nominal diameter,” “size,” and “nominal size.”

ASTM A335 Seamless Ferritic Alloy-Steel Pipe for High-Temperature service. Pipe ordered to this specification shall be suitable for bending, flanging, and similar forming operations, and for fusion welding.  Sometimes referred to as “P Grade”, chrome moly pipe is popular in P-Grades P5, P9, P11, P22, and P91.  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. 
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.   

Grades: P-5, P-9, P-11, P-22, and P-91 
Sizes 
NPS 1/4” to NPS 48”  
Wall Thickness – Schedules 10 through 160, STD, XS, XXS.  
Unscheduled heavy wall pipe thicknesses available up to 4 inches.

Grade

C

Mn

P

S

Si

Cr

Mo

P5

0.15max

0.30-0.60

0.025

0.025

0.50 max

4.00-6.00

0.45-0.65

P9

0.15 max

0.30-0.60

0.025

0.025

0.25-1.00

8.00-10.00

0.90-1.10

P11

0.05-0.15

0.30-0.60

0.025

0.025

0.50-1.00

1.00-1.50

0.44-0.65

P22

0.05-0.15

0.30-0.60

0.025

0.025

0.50 max

1.90-2.60

0.87-1.13

P91

0.08-0.12

0.30-0.60

0.020

0.010

0.20-0.50

8.00-9.50

0.85-1.05

V 0.18-0.25

N 0.03-0.07

Ni 0.40 max

Al 0.02 max

Cb 0.06-0.10

Ti 0.01 max

Zr 0.01 max


Mechanical Properties

Grade P11, P22, P5, P9  Grade P91
Tensile strength, min, psi, (MPa)   60,000 (415)    85,000 (585)
Yield strength, min, (MPa) 30.000 (205)  60,000 (415)

(Note: This is summarized information from ASME Specification A335. Please refer to the specific Standard or Specification or contact us for more details.)

Permissible Variations in Diameter

For pipe ordered to NPS or outside diameter, variations outside diameter shall not exceed those specified following: 

NPS Designator

Over

Under

In.mm

In.mm

1⁄8to 11⁄2, incl.

1⁄64 (0.015) 0.40

1⁄64 (0.015) 0.40

Over 11⁄2 to 4, incl.

1⁄32 (0.031) 0.79

1⁄32 (0.031) 0.79

Over 4 to 8, incl.

1⁄16 (0.062) 1.59

1⁄32 (0.031) 0.79

Over 8 to 12, incl.

3⁄32 (0.093) 2.38

1⁄32 (0.031) 0.79

Over 12 6 1 % of the pacified outside diameter 
For pipe ordered to inside diameter, the inside diameter shall be not vary more than ±1 % from the specified inside diameter.

Packing: Bare packing/bundle packing/crate packing/wooden protection at the both sides of tubes and suitably protected for sea-worthly delivery or as requested. 
Inspection and Test: Chemical Composition Inspection, Mechanical Properties Test(Tensile Strength, Yield Strength, Elongation, Flaring, Flattening, Bending, Hardness, Impact Test), Surface and Dimension Test, No-destructive Test, Hydrostatic Test. 
Surface treatment: Oil-dip, Varnish, Passivation, Phosphating, Shot Blasting.
Both ends of each crate will indicate the order no., heat no., dimensions, weight and bundles or as requested.

Related News

العربية简体中文NederlandsEnglishFrançaisDeutschItaliano한국어РусскийEspañolไทยTürkçe