ASTM A790 pipe is a special type of stainless steel pipe, whose micro structure is mainly composed of austenite and ferrite. The austenite phase provides good toughness, corrosion resistance, high strength and good processability, while the ferrite phase enhances the steel’s resistance to stress corrosion cracking, thermal conductivity and resistance to chloride stress corrosion cracking. Therefore, duplex stainless steel pipes usually have the characteristics of high strength, good corrosion resistance, excellent welding performance and high thermal conductivity.

Duplex stainless steel pipes also have a lower linear expansion coefficient, which makes it have better dimensional stability at high temperatures. These characteristics make duplex stainless steel pipes widely used in petroleum, chemical, seawater desalination, paper making, and many other industrial fields.

ASTM A790 Pipe Standard

This specification covers seamless and straight-seam welded ferritic/austenitic steel pipe intended for general corrosive service, with particular emphasis on resistance to stress corrosion cracking. These steels are susceptible to embrittlement if used for prolonged periods at elevated temperatures.

 Appendix X1 of this specification lists the dimensions of welded and seamless stainless steel pipe as shown in ANSI B36.19. Pipe having other dimensions may be furnished provided such pipe complies with all other requirements of this specification.

Features

Material Composition: The standard covers duplex stainless steel, which is characterized by a balanced microstructure of austenite and ferrite. This composition offers superior mechanical properties and corrosion resistance compared to standard austenitic stainless steels.

Seamless and Welded: The specification includes both seamless and welded pipes, offering flexibility in manufacturing and application.

Corrosion Resistance: Duplex stainless steel pipes under this specification exhibit excellent resistance to a wide range of corrosive environments, including chlorides and sulfides, making them ideal for use in harsh conditions.

Mechanical Properties: The duplex structure provides high strength and good impact toughness, which is advantageous in many industrial applications.

Specification of ASTM A790 Pipes

ASTM A790 pipe specifications are mainly applicable to sizes ranging from 1/8”to 30”(DN6 to DN750). The wall thickness of these steel pipes must comply with ASME B36.19 standards, and the wall thickness grades are SCH 10, SCH 20, SCH 40, STD, XS, SCH 100, SCH 120, SCH 160, XXS.

Processing Method	Seamless and Welded
Size Range	1/8” – 30” / DN6 – 750
Thickness Schedule	SCH10 SCH20 STD SCH40 SCH60 SCH80 SCHXS SCH100 SCH120 SCH140 SCH160 SCHXXS
Length	6m or 12 m or Random
Standard	ASME B36.19,ASTM A789, ASTM A790, ASTM A928, ASME SA789,
Surface Treatment	Polish , Mirror , Epoxy Powder FBE, 2PE, 3PE Coating
Material Grade	ASTM A790 S32205, S31803, 32750, 32760, S32550
Pipes Ends	Plain Ends / Beveled Ends

ASTM A790 Material Analysis

The chemical composition of ASTM A790 steel pipe mainly includes alloy elements such as chromium, nickel, molybdenum, etc. The reasonable combination of these alloy elements gives the steel pipe excellent corrosion resistance and mechanical properties.

UNS	EN	DIN	LIMITS	C	Mn	P	S	Si	Ni	Cr	Mo	N
ASTM A790 S31803	1.4462	X2CrNiMoN22-5-3	MIN						4.5	21	2.5	0.08
			MAX	0.03	2	0.03	0.02	1	6.5	23	3.5	0.2
ASTM A790 UNS S32205	1.4462	X2CrNiMoN22-5-3	MIN						4.5	22	3	0.14
			MAX	0.03	2	0.03	0.02	1	6.5	23	3.5	0.2
ASTM A790 UNS S32750	1.441	X2CrNiMoN25-7-4	MIN						6	24	3	0.24
			MAX	0.03	1.2	0.035	0.02	0.8	8	26	5	0.32
ASTM A790 S32760			MIN							24	3
			MAX	0.03	1	0.03				26	4

ASTM A790 Pipe Mechanical Property

ASTM A790 material has high strength and good toughness. The tensile strength is above 620 MPa. This high strength property enables the steel pipe to withstand greater pressure and load, and is suitable for high-pressure pipeline systems, petrochemicals and other fields.

MATERIAL	T.S (MPA)	Y.S (MPA)	EL %	HARDNESS
ASTM A790 S31803	620min	450min	25min	290max
ASTM A790 S32205	655min	450min	25 min	290max
ASTM A790 S32750	800min	550min	15min	300max
ASTM A790 S32760	750min	550min	25min	310max

Characteristics of Duplex Stainless Steel Pipes

High Precision : ASTM A790 pipes are manufactured with strict dimensional tolerances, ensuring consistent and accurate dimensions along their entire length.

Smooth Surface Finish : These pipes have a smooth surface finish, which is essential for applications where fluid flow or the passage of precision instruments is involved.

Uniform Mechanical Properties : Precise control over the manufacturing process results in uniform mechanical properties, including tensile strength, yield strength, and elongation, which is important for reliable performance.

Customizable : ZIZI can be produced in various sizes, shapes, and grades to meet the specific requirements of different industries and applications.