ASTM A53 Standard specification covers Seamless and Welded, Black and Hot-Dipped Galvanized nominal (average) wall pipe for coiling, bending, flanging and other special purposes and is suitable for welding.

The steel for both seamless and welded pipe shall be made by one or more of the following processes: open-hearth, electric furnace, or basic-oxygen. The weld seam of electric-resistance welded pipe in Grade B shall be heat treated after welding.

A53 pipe comes in three types and two grades

This is a standard set by the standards organization ASTM International, a voluntary standards development organizations that sets technical standards for materials, products, systems, and services.

This specification covers Seamless and Welded, Black and Hot-Dipped Galvanized nominal (average) wall pipe for coiling, bending, flanging and other special purposes and is suitable for welding. Continuous-Welded pipe is not intended for flanging. Purpose for which pipe is intended should be stated on order. It shall be permissible to furnish pipe having other dimensions provided that such pipe complies with all other requirements of this specification. Supplementary requirements of an optional nature are provided and shall apply only when specified by the purchaser.

Note 1. The dimensionless designators NPS (nominal pipe size) [DN (diameter nominal)] have been substituted in this specification for such traditional terms as 'nominal diameter,' 'size,' and ‘nominal size.’

Note 2. The term nominal wall thickness has been assigned for the purpose of convenient designation, existing in name only, and is used to distinguish it from the actual wall thickness, which may vary over or under the nominal wall thickness.

The minimum wall thickness at any point shall not be more than 12.5% under the nominal wall thickness specified.

Weight of any length shall not vary more than 10% over and 3.5% under that specified.

NOTE-NPS 4 and smaller-weighed in lots. Larger sizes shall be weighed separately by length.

Chemical elements	Type S		Type E		Type F
	(SMLS)		(ERW)		(FW)
	Gr. A	Gr.B	Gr. A	Gr. B	Gr. A
Carbon max. %	0.25	0.3	0.25	0.3	0.3
Manganese %	0.95	1.2	0.95	1.2	1.2
P, max. %	0.05	0.05	0.05	0.05	0.05
Sulfur, max. %	0.045	0.045	0.045	0.045	0.045
Copper, max.%	0.4	0.4	0.4	0.4	0.4
Nickel, max. %	0.4	0.4	0.4	0.4	0.4
Chromium, max. %	0.4	0.4	0.4	0.4	0.4
Mo, max. %	0.15	0.15	0.15	0.15	0.15
Vanadium, max. %	0.08	0.08	0.08	0.08	0.08

The total composition for these five elements shall not exceed 1.00%.

Properties	SMLS & ERW		Con. welded
	Grade A	Grade B	Grade
Tensile Strength, min., psi	48,000	60,000	45,000
Yield Strength, min., psi	30,000	35,000	25,000

• Seamless and Electric-Resistance-Welded — Bending, flattening, tensile on one length of pipe from each lot of 500 lengths or less of a size.
• Continuous-Weld — Bending, flattening, tensile
• Con. welded: Continuous-welded

Couplings — Applied handling tight. Couplings, 2″ and smaller straight tapped, other sizes taper tapped.

Thread Protection — Applied to pipe 4″ and larger.

End Finish (unless otherwise specified) –

STD or XS, or wall thicknesses less than 0.500 in. (excluding XXS): Plain and beveled

All XXS and wall thicknesses over 0.500 in.: Plain end square cut.

Hydrostatic inspection test pressures for plain end and threaded and coupled pipe are specified. Hydrostatic pressure shall be maintained for not less than 5 seconds for all sizes of seamless and electric-resistance-weld pipe.

Flattening Test — NPS 2 and larger STD and XS. (Not required for XXS pipe.)