ASTM A335 Seamless Alloy Steel Pipe specification

Mar 01, 2024

ASTM A335 Seamless Alloy Steel Pipe pecification

Scope: This specification covers nominal and minimum wall thickness seamless chromium-molybdenum seamless pipe for use in the power generation and petrochemical industries. ASTM A335 seamless steel pipe ordered in accordance with this specification shall be suitable for welding, bending, flanging (vanstoning) and similar forming operations. With the addition of chromium and molybdenum, ASTM A335 has good tensile strength, good resistance to high temperatures and corrosion.

Level and application:
Covering P1 to P5, P9, P11, P12, and P91 steel grades. P11/P22 and P91/92 grades are commonly used in power stations, while A335 grades P5 and P9 are mainly used 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
Application areas: industrial boilers, power plants, nuclear power plants

ASTM A335 Steel Pipe Chemical Composition:

Material	C	Si	Mn	P	S	Mo	Cr
	%	%	%	%	Max	%	Max
A335 Grade P1	0.10---0.20	0.10---0.50	0.30---0.80	0.025	0.025	0.440.65
A335 Grade P5	Max 0.15	Max 0.50	0.30---0.60	0.025	0.025	0.450.65	4.006.00
A335 Grade P11	0.05---0.15	0.5---1.0	0.30---0.60	0.025	0.025	0.450.65	1.001.50
A335 Grade P12	0.05---0.15	Max 0.50	0.30---0.61	0.025	0.025	0.450.65	0.801.25
A335 Grade P22	0.05---0.15	Max 0.50	0.30---0.60	0.025	0.025	0.871.13	1.902.60

ASTM A335 Steel Pipe Mechanical Properties:

Material	Tensile N/mm2	Strength min N/mm2	Yield %min
A335 Grade P1	Min380	205	30
A335 Grade P5	Min415	205	30
A335 Grade P11	Min415	205	30
A335 Grade P12	Min415	205	30
A335 Grade P22	Min415	205	30

ASTM A335 Steel Pipe Heat Treatment Requirements

ASTM A335 steel pipe may be either hot finished or cold drawn with the finishing heat treatment noted below.

ASTM A335 Grade	Heat Treatment Type	Normalizing Temperature Range F [C]	Subcritical Annealing or Tempering Temperature Range F [C]
P5 (b,c)	Full or Isothermal Anneal
	Normalize and Temper	-	1250 [675]
	Subcritical Anneal (P5c only)	-	1325 - 1375 [715 - 745]
P9	Full or Isothermal Anneal
	Normalize and Temper	-	1250 [675]
P11	Full or Isothermal Anneal
	Normalize and Temper	-	1200 [650]
P22	Full or Isothermal Anneal
	Normalize and Temper	-	1250 [675]
P91	Normalize and Temper	1900-1975 [1040 - 1080]	1350-1470 [730 - 800]
	Quench and Temper	1900-1975 [1040 - 1080]	1350-1470 [730 - 800]

ASTM A335 steel pipe Permissible Variation in Wall Thickness

NPS [DN] Designator	Tolerance, % from Specified
	Over	Under
1/8 to 2 1/2 [6 to 65] incl., all t/D ratios	20.0%	12.5%
Above 2 1/2 [65], t/D < or = 5%	22.5%	12.5%
Above 2 1/2 [65], t/D > 5%	15.0%	12.5%
(t = Specified Wall Thickness; D = Specified Outside Diameter)

ASTM A335 Steel Pipe Elongation Requirements:

Calculated Minimum Elongation Values
Elongation in 2 in. or 50 mm, min %
Wall Thickness		P5, P9, P11, P22		P91
in.	mm	Longitudinal	Transverse	Longitudinal
5/16 (0.312)	8	30	20	20
9/32 (0.281)	7.2	28	19	19
1/4 (0.250)	6.4	27	18	18
7/32 (0.219)	5.6	26		17
3/16 (0.188)	4.8	24		16
5/32 (0.156)	4	22		15
7/8 (0.125)	3.2	21		14
3/32 (0.094)	2.4	20		13
1/18 (0.062)	1.6	18		12

ASTM A335 Steel Pipe Permissible Variations in Outside Diameter:

Outside Diameter at any point shall not vary from standard specified more than:

NPS [DN] Designator	Over		Under
	in.	mm	in.	mm
1/8 to 1 1/2 [6 to 40], incl.	1/64 (0.015)	0.40	1/64 (0.015)	0.40
Over 1 1/2 to 4 [40 to 100], incl.	1/32 (0.031)	0.79	1/32 (0.031)	0.79
Over 4 to 8 [100 to 200], incl.	1/16 (0.062)	1.59	1/32 (0.031)	0.79
Over 8 to 12 [200 to 300], incl.	3/32 (0.093)	2.38	1/32 (0.031)	0.79
Over 12 [300]	+/- 1% of the specified outside diameter

ASTM A335 Steel Pipe Mechanical Tests Specified:

The steel material shall conform to chemical composition, tensile property, and hardness requirements. Each length of pipe shall be subjected to the hydrostatic test.

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.
	The inside diameter of the bend shall be 1 inch [25 mm].
Hydrostatic Test	Each length of pipe shall be Hydro tested, at option of manufacture nondestructive electric testing can be used.