Learn about the alloy steel pipes specification ASTM A335 that covers “chrome-moly” seamless pipes with remarkable resistance to corrosion and good tensile strength at high-temperature service. Generally, ASTM A335 P11, P22, and P91 pipes are used in power generation and in downstream oil and gas, P5 and P9 grades are for refinery applications.
ALLOY PIPE A335
How to define alloy pipes?
Alloy pipes are tubular with higher percentages, than standard carbon steel pipes, of alloying elements as Molybdenum (Mo), Chromium (Cr), Nickel, etc. Actually, the ASTM A335 covers “low-alloy” steel pipes, i.e. pipes that have a total amount of alloying elements below 5%. The addition of higher percentages of alloying elements (example Nickel and Chromium) transforms the steel into higher alloys, like stainless steel, duplex, up to super-alloyed materials like Inconel, Hastelloy, Monel, etc.
Alloy steel pipes are used in the energy industry for high temperature and very low-temperature service (cryogenic), or for applications with very high pressures.
ASTM A335 alloy steel pipes fit ASTM A234 WPx series buttweld fittings (WP5, WP9, WP91) and A182 Fx forged fittings and flanges (A182 F5, F9, F11, F22, F91). All these materials have similar chemical and mechanical properties and can be joined or welded.

Alloying elements
The addition of Molybdenum (“Moly”) increases the strength of the steel and its elastic limit, enhance the steel resistance to wear, its impact qualities, and the hardenability. It also improves the resistance to softening, makes chromium steel less prone to embrittlement and prevents pitting.
- Aluminum: decreases oxygen from steelmaking
- Boron: used to produce fine grain size and enhance steel hardness
- Cobalt: used to enhance the steel’s heat and wear-resistance
- Manganese: gives better steel hardenability
- Nickel: Enhances toughness, hardenability and impact strength at low temperatures
- Silicon: decreases oxygen, enhances hardenability and toughness
- Titanium: prevents precipitation of chromium carbide
- Tungsten: refines steel grain size and enhance the steel hardness, especially at high temperatures
- Vanadium: gives steel enhanced fatigue resistance
As mentioned, low-alloy steels have a total amount of alloying elements below 5%; high alloy steel has a higher percentage of these elements.
A335 PROPERTIES
CHEMICAL COMPOSITION
The types of alloy steel covered by the ASTM A335 – ASME SA335 specification are designed with a “P” prefix, from P5 to P92. Grades P11/P22 and P91/92 are typically found in power stations, whereas grade P5 and P9 are more common for application in the petrochemical industry. Grades P9, P91 are, in the list, the more expensive (a P91 seamless pipe may cost approx 5€ per kg.).
ASTM A335 Low-Alloy Steel (Grades) |
UNS equivalent |
C≤ | Mn | P≤ | S≤ | Si≤ | Cr | Mo |
P1 | K11522 | 0.10~0.20 | 0.30~0.80 | 0.025 | 0.025 | 0.10~0.50 | – | 0.44~0.65 |
P2 | K11547 | 0.10~0.20 | 0.30~0.61 | 0.025 | 0.025 | 0.10~0.30 | 0.50~0.81 | 0.44~0.65 |
P5 | K41545 | 0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 4.00~6.00 | 0.44~0.65 |
P5b | K51545 | 0.15 | 0.30~0.60 | 0.025 | 0.025 | 1.00~2.00 | 4.00~6.00 | 0.44~0.65 |
P5c | K41245 | 0.12 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 4.00~6.00 | 0.44~0.65 |
P9 | S50400 | 0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.50~1.00 | 8.00~10.00 | 0.44~0.65 |
P11 | K11597 | 0.05~0.15 | 0.30~0.61 | 0.025 | 0.025 | 0.50~1.00 | 1.00~1.50 | 0.44~0.65 |
P12 | K11562 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 0.80~1.25 | 0.44~0.65 |
P15 | K11578 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 1.15~1.65 | – | 0.44~0.65 |
P21 | K31545 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 2.65~3.35 | 0.80~1.60 |
P22 | K21590 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 1.90~2.60 | 0.87~1.13 |
P91 | K91560 | 0.08~0.12 | 0.30~0.60 | 0.02 | 0.01 | 0.20~0.50 | 8.00~9.50 | 0.85~1.05 |
P92 | K92460 | 0.07~0.13 | 0.30~0.60 | 0.02 | 0.01 | 0.5 | 8.50~9.50 | 0.30~0.60 |
MECHANICAL PROPERTIES
Hardness | ||||||
A335 Low-Alloy Pipe | UNS Number | Yield Strength ksi | Tensile Strength ksi | Elongation % | Rockwell | Brinell |
P1 | K11522 | 30 | 55 | 30 | – | – |
P2 | K11547 | 30 | 55 | 30 | – | – |
P5 | K41545 | 40 | 70 | 30 | – | 207 max |
P9 | S50400 | 30 | 60 | 30 | – | – |
P11 | K11597 | 30 | 60 | 20 | – | – |
P12 | K11562 | 32 | 60 | 30 | – | 174 max |
P22 | K21590 | 30 | 60 | 30 | – | – |
P91 | K91560 | 60 | 85 | 20 | – | – |
TESTING REQUIREMENTS
- Transverse/longitudinal: tension and flattening, hardness, bend tests- for material which has been heat-treated in batch furnaces, these tests shall be made on the 5% of the pipes from each heat lot number. For smaller lots, one pipe at a minimum has to be tested
- ASTM A335 Gr. P91 shall have a hardness of 250 HB / 265 HV (25 HRC)
- Hydro testing: shall be applied to every length of pipe
- The non-destructive electric test is optional
TOLERANCES
DIAMETER
A335 Pipe | Over | Under | ||
NPS [DN] | in. | mm | in. | mm |
1/8 to 1 1/2 / DN 6 to 40 | 1/64 (0.015) | 0.4 | 1/64 (0.015) | 0.4 |
Over 1 1/2 to 4 / DN 40 to 100 | 1/32 (0.031) | 0.79 | 1/32 (0.031) | 0.79 |
Over 4 to 8 / DN 100 to 200 | 1/16 (0.062) | 1.59 | 1/32 (0.031) | 0.79 |
Over 8 to 12 / DN 200 to 300 | 3/32 (0.093) | 2.38 | 1/32 (0.031) | 0.79 |
Over 12 / > DN 300 | +/- 1% of the specified outside diameter |
WALL THICKNESS
The tolerances in WT, in %, from specified are:
- 1/8 to 2 1/2 [6 to 65] incl., all t/D ratios: over 20%, under 12.5%
- Above 2 1/2 [65], t/D < or = 5%: over 22.5%, under 12.5%
- Above 2 1/2 [65], t/D > 5%: over 15%, under 12.5%
t = Specified Wall Thickness; D = Specified Outside Diameter)
ALLOY PIPE CROSS REFERENCE TABLE ASTM vs. EN GRADES
Chrome Moly Pipes: Werkstoff vs EN vs ASTM | ||
---|---|---|
Werkstoff /DIN | EN | ASTM |
1.5415 | 16Mo3 | A335 Grade P1 |
1.7335 | 13CrMo4-5 | A335 Grade P11, P12 |
1.7380 | 10CrMo9-10 | A335 Grade P22 |
1.7362 | X11CrMo5 | A335 Grade P5 |
A335 Grade P9 | ||
1.4903 | X10CrMoVNb9-1 | A335 Grade P91 |
ALLOY STEEL PIPE MANUFACTURERS
Pipe Mill | Country |
Jiangu Chengde Steel Tube Co Ltd. Ltd | China |
Chomutov | Czech |
Eschweiller(Bentler) | Germany |
Vallourec Tubes | Germany, France, & Brazil |
Tenaris | Italy, Mexico, & Argentina |
Sumitomo Metal | Japan |
JFE | Japan |
Productos Tubulares | Spain |
Tubos Reunidos | Spain |
Wyman Gordon | USA |
Michigan Seamless | USA |
Rockwell Collins | USA |
We recommend purchasing the ASTM A335 specification from the ASTM website or the IHS store to get a complete understanding of this topic.
20 Responses
We are looking 15000 Kg Chrome Vanadium Molybdenum Seamless Tube. Pls advise your email ID to send more details
We are looking 15000 Kg Chrome Vanadium Molybdenum Seamless Tube. Pls advise your email ID to send more details
40 ft- 6″ Sch-100 A-335 Gr. WP-9 Seamless
20 ft- 8″ –DItto–
140 ft- 12″ –Ditto–
360 ft- 30″ Sch- .375″ A-335 Gr. WP-9 Welded
please email your all requirements on [email protected] for all type of fittings flanges, pipes & sheets.
40 ft- 6″ S-100 A335 P-9 Seamless Pipe
20 ft- 8″ –Ditto–
140 ft- 12″ –Ditto–
360 ft- 30″ .375″ Wall A335 P-9 Welded Pipe
Kindly send your requirement of buttweld pipe fittings, forged fittings, and flanges by mail to us at [email protected]
Required material
1.5415
and
1.4835 or 1.4828
Rate per ton
Please send your requirements by visiting this page: https://projectmaterials.com/submit-rfq-mto. Best regards, Projectmaterials
WE NEED FOR URGENT DELIVERY THE FOLLOWING A335 GRADE P11 PIPE:
ITEM 1: SPEC 610.00MM X 9.53MM (DIAM 24″) SCHED 20/STD (ASME B36.10): 12 METERS
ITEM 2: SPEC 914.00MM X 9.53MM (DIAM 36″) SCHED 20/STD (ASME B36.10): 12 METERS
IMMEDIATE AVAILABILITY IS A MUST. PLEASE PROVIDE PRICE, DELIVERY AND COUNTRY OF ORIGIN (MATERIAL CERTIFICATES MUST BE INCLUDED IN PRICE).
IF NEEDED, CALL ME AT 281-989-7259.
THANK YOU!!
already sent your order by ship
We have these pipes. Please email us on [email protected]
I can supply A335 P11 pipe to you, please contact me. [email protected]
We need 2 each of IP By-Pass Pipe Spool,
Dia: 30 inch, Wall Thickness: 25 mm,
Material: A-335 Gr P91,
Length: 1000 mm (Seamless pipe) with bevels, Fluid-Steam, Pressure-10 Bar, Temperature-574°C
together with Data Sheet.
Bid Closing date : 10th May, 2020.
Delivery Terms: Ex- Works and CIF Doha, Qatar.
We urgently need 2 each of IP By-Pass Pipe Spool, Dia: 30 inch, Wall Thickness: 25 mm, Material: A-335 Gr P91, Length: 1000 mm (Seamless pipe) with bevels, Fluid-Steam, Pressure-10 Bar, Temperature-574°C, as per attached drawing, on or before 19th May, 2020.
Delivery Terms : DDP Qatar/ CIF Doha Port/ Ex-Works(Provide Packing details with dimension)
Also include all the following details when quoting.
1. Packing charges
2. Documentation charges.
3. Datasheet.
astm a355 p91 1.50 sch xxs
OK
Need p91 with certificate urgent
We sell all kind of ASTM A335/SA335 alloy pipes P5, P9, P22, P91(Type1 & Type2), http://www.vicsteelpipe.com [email protected]
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Dear sir
I am a commercial mediation office. I work with the Iraqi Ministry of Oil. I have a set of tenders. Please see the attachments
[ But we need an uk origin
If there is a possibility of that
Although all documents are uk
See atached …….. pls reply
Best Regards
Diab M. Hassan
Email: [email protected]
Address: Iraq / Erbil / Ozal City / No.4/150
Mobile: +9647712324945
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