ASTM A672 EFW Pipes & Tubes

ASTM A672 - Standard Specification for Electric Fusion Welded Steel Pipe for High Pressure Service at Moderate Temperatures.

Scope of application:
This standard applies to electric fusion welded (EFW) pipes, which are mainly used in industrial piping systems under medium temperature and high pressure environments, such as oil, natural gas, chemical, power and other industries.
Applicable temperature: Usually used in medium temperature environments of -29°C to 427°C (-20°F to 800°F), and some grades can withstand higher temperatures for a short time.

Size range:
Outer diameter: ≥16 inches (406 mm)
Wall thickness: ≤3 inches (75 mm)

Material grade:
Based on different steel plate standards (such as ASTM A285, A515, A516), it is divided into A, B, and C series (such as A55, B60, C70, etc.), numbers (55/60/65/70, etc.): indicates the minimum tensile strength (unit: ksi, such as 60 = 60 ksi ≈ 415 MPa)

This specification covers electrical fusion welded steel pipe for high-pressure service at moderate temperatures. Heat treatment may or may not be required to attain the desired properties or to comply with applicable code requirements. An analysis of each mill heat of plate material shall be made, also, an analysis of the finished deposited weld material from each 500 ft or fraction thereof shall be made. The mechanical test requirements includes one tension test specimen to represent each lot of finished pipe, and one transverse-guided-weld-bend test (two specimens) to represent each lot of finished pipe. Also, radiographic examination shall be made on the full length of each weld.

Manufacturing process:

It is manufactured using the electric fusion welding (EFW) process, which can ensure the quality and strength of the weld, so that the welded pipe can still maintain stable performance when subjected to complex working conditions such as high pressure and high temperature.

Nondestructive testing (NDT): Welds need to be tested by radiographic testing (RT) or ultrasonic testing (UT)
Hydrostatic testing: Each steel pipe needs to be tested by hydrostatic pressure to ensure pressure bearing capacity

Chemical Requirements of ASTM A672 :

Specification	Steel grade	Chemical composition						Remarks
		C	Si	Mn	P	S	Ti
Pipes for pressure service  ASTM A671, ASTM A672	-/A45	-/0.17	-	0.98	0.035	0.035	-	A671/ A672
	-/A50	-/0.22	-
	CA55/A55	0.28	-
	-/B55	-/0.20	0.13 ~0.45
	CB60/B60	0.24
	CB65/B65	0.28
	CB70/C70	0.31		1.30
	-/C55	-/0.18		0.55 ~0.98
	CC60/C60	0.21
	CC65/C65	0.24		0.79 ~1.30
	CC70/C70	0.27

Mechanical Properties of ASTM A672:

Products	Steel Grade	BASE METAL MECHANICAL COMPOSITION				Welding point tensile strength (N/mm2)	Remarks
		Yield point (N/mm2)	Tensile Stregth (N/mm2)	Test Pieces	Elongation (%)
Pipes for pressure service ASTM A671, ASTM A672	-/A45	-/165	-/310~450	-	-/30	-/310~450	A671/ A672
	-/A50	-/185	-/345~485		-/28	-/345~485
	CA55/A55	205	380~515		27	380~515
	-/B55	-/205	-/380~515		-/27	-/380~515
	CB60/B60	220	415~550		25	415~550
	CB65/B65	240	450~585		23	450~585
	CB70/B70	260	485~620		21	485~620
	-/C55	-/205	-/380~515		-/27	-/380~515
	CC60/C60	220	415~550		25	415~550
	CC65/C65	240	450~585		23	450~585
	CC70/C70	260	485~620		21	485~620

Comparison of similar standards:
ASTM A671: Low temperature (above -45°C), low temperature pressure pipeline
ASTM A672: Medium temperature (-29°C~427°C), medium temperature high pressure pipeline
ASTM A691: High temperature (up to 650°C), high temperature and high pressure pipeline

Typical applications:
Oil & Gas: High pressure gas pipelines, LNG facilities.
Chemical industry: Corrosive media transmission pipelines.
Power industry: Thermal power plant steam pipelines, boiler systems.

ASTM A672 is a standard for electric fusion welded steel pipes specifically for medium temperature and high pressure environments, suitable for petroleum, chemical, power and other industries. Its material grade is based on different steel plate standards, and the manufacturing process must strictly follow the welding, testing and heat treatment requirements to ensure safety and reliability under high pressure environments.

Read more: Carbon Steel EFW pipe or ERW vs EFW Pipe