A335 Seamless Chrome Molybdenum Pipe

A335 seamless chromium-molybdenum pipe is a kind of seamless alloy steel pipe for high temperature. Because of its good oxidation resistance, high temperature strength and sulfide corrosion resistance, it is widely used in high temperature, high pressure, flammable and explosive petroleum refining equipment. The pipes, especially the directly heated pipes of the heating furnace, can reach a medium temperature of 550~600℃.
A335 seamless chromium-molybdenum pipe is produced in accordance with the American ASTM A335 standard. Its materials mainly include P5, P9, P11, P22, P91, etc. The similar domestic steel grades are 1Cr9Mo, 15CrMo, 12Cr1MoV, 12Cr2Mo, etc., which respectively correspond to the P9, P11, P22, P91 and other materials of A335.

Specification	ASTM A335
Material Grade	P5, P9, P11, P22, P91, etc.
Equivalent Domestic Material	1Cr9Mo, 15CrMo, 12Cr1MoV, 12Cr2Mo, etc.
Application	Boiler, Superheater, Reheater, Water Wall Header, Economizer, Low-Temperature Superheater and Reheater, Condenser Tubes, etc.
Key Features	Good creep resistance, high tensile strength, oxidation resistance, corrosion resistance
Manufacturing Processes	Steel making, rolling, heat treatment, non-destructive testing, etc.
Quality Assurance	Strict inspection and testing to ensure compliance with standards and specifications

ASTM A335 Chrome Moly pipes Permissible Variations in Outside Diameter

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