ASTM A335 P9 Pipe Specification (Chrome Moly Pipe)

ASTM A335 P9/ ASME SA335 P9 is Seamless Ferritic Chrome Moly Alloy Pipe used for high-temperature services. P9 Pipe Chrome content at 8.00% to 10.00 %, Moly content 0.90% to 1.10%, Minimum tensile strength 415MPa, minimum yield strength 205Mpa.

ASTM A335 P9 is Chrome Moly Pipe

ASTM A335 / ASME SA335 Pipe named chrome moly pipe as they have a high level of Chromium and Molybdenum.

Chromium will increase oxidation resistance and provides high-temperature strength, along with the better tensile & yield strength and proper hardness at room temperature. When the chromium levels are above 12%, it can be classified as stainless steel.

Molybdenum increases the overall strength, resistance, elasticity, hardenability and overall quality, moly ensures that the material is more resistant to softening, restrains the growth of grains and lessens the chances of embrittlement. It is the single additive that is responsible for the increase in high temperature resistance (to 540-750°C) and it also improves the corrosion resistance to steel.

A335/SA335 P9 Corresponding to ASTM A234 WP9, ASTM A182 F9, ASTM A387 Grade 9

P9 pipe material has high toughness and high wear and tear resistance, it could be used in oil and gas pipelines and also  could be used to manufacture pipe fittings like elbow, tee, reducers, and flanges, related standards as below:

Pipe fittings standard: ASTM A234 WP9
Flange Standard: ASTM A182 F9
Equivalent Steel Plate Standard: ASTM A387 Grade 9/ ASME SA387 Grade 9

ASTM A335 P9/ASME SA355 P9 Data Sheet

Chemical Composition and for other P grade Pipe (P5, P11, P22, P91)

P9 Pipe Tensile Strength, Yield Strength

Elongation

Elongation in 2 in or 50mm or 4D minimum%:
For wall thickness 5/16 in [8mm] and over: Longitudinal 30% and Transverse 20%.

Elongation smaller 2 in or 50mm or 4D minimum%:
For wall thickness 5/16 in [8mm] and over: Longitudinal 22% and Transverse 14%.

For strip tests a deduction of each 0.8mm below 8mm shall be calculated with the Table 5 in ASTM A335.

Tolerances

Inside diameter not vary more than 1% from specified ID in the PO.
Outside diameter for 6mm to 40mm, vary +/-0.40mm.
For OD 40 to 100mm, +/-0.79mm.
OD 100 to 200mm, +1.59/-0.79mm.
OD 200 to 300, +2.38/-0.79mm.
Over 300mm 12 inch, +/-1% from specified OD in the PO.

Wall Thickness Tolerance

DN6 to 65, +20%/-12.5%
Abover DN65 t/D ≤5%A, +22.5%/-12.5%
Abover DN65 t/D ＞5%A, +22.5%/-12.5%

At= Specified Wall Thickness; D = Specified Outer Diameter

Referred standards of producting ASTM A335 P9 Pipe

a. ASTM A999/ A999M, Standard specification for common requirements for stainless and alloy steel pipe
b. ASTM A92, Hardness test methods for steel materials
c. E213, Instructions and practice for ultra sonic testing of steel pipe and tube
d. E309 Eddy-Current Examniation methods for steel pipe products
e, E381, Inspection methods for steel bars, beams, profiles, billets and forgings.
f, E527, Numbering metals and alloys practices
g, E570, Instructions for flux leakage examniation of ferromagnetic steel pipe products

Tests

Tensile tests: Transverse and Longitudinal
Flattening test
Hardness test not exceeding 250 HBW/265 HV30 [25HRC]
Bend Test shall be carried as per ASTM A370
Hydrostatic Test shall be carried , depending on the buyer a nondestructive examination shall be performed plus with hydrostatic test.

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