ASTM A789 UNS S31803 Duplex Stainless Pipe

What material is ASTM A789 ?

ASTM A789 is a standard specification from ASTM International for seamless and welded duplex stainless steel tubing for general service applications requiring good corrosion resistance, particularly to stress corrosion cracking. It defines various grades of ferritic/austenitic stainless steel, such as S31803 and S32205, and specifies requirements for manufacturing, testing (including hydrostatic and electric tests), and heat treatment to ensure the tubing's structural integrity and performance.

 

What is the difference between ASTM A790 and A789?

ASTM A789 is for small size tubes and tubing, mainly used for Pressure vessel such as Heat Exchanger. ASTM A790 is big size stainless steel pipe, mainly used for fluid transportation. Both include Seamless and Welded.

 

What is SA789 S31803 seamless pipe made of?
SA789 S31803 refers to the ASTM A789 duplex stainless steel pipe standard, specifically the UNS S31803 grade. This duplex stainless steel alloy features a dual-phase microstructure (austenite and ferrite), offering high strength and excellent resistance to general corrosion, localized corrosion, and stress corrosion cracking. Its primary elements, approximately 22% chromium, 3% molybdenum, and approximately 5-6% nickel and nitrogen, make it suitable for harsh environments in industries such as oil and gas, desalination, and chemical processing.

 

Chemical composition for ASTM A789 UNS S31803 tubing, %

C	≤0.030
Mn	≤2.00
P	≤0.030
S	≤0.020
Si	≤1.00
Ni	4.5-6.5
Cr	21.0-23.0
Mo	2.5-3.5
N	0.08-0.20

 

Mechanical Properties of SA 789 UNS S31803 ERW Tube

Tensile Strength,min.	Yield Strength,min.	Elongation,min.	Hardness Brinell, max
Mpa	Mpa	%	HB
620	450	25	290

 

A789 UNS S31803 Heat Exchanger Tubes Temperature Range

Product	Temperature Range
UNS S31803 Tubing	Up to 600°F (316°C)

 

ASTM A789 UNS S31803 Tube Price List

Price list	Price in USD
ASTM A789 UNS S31803 Tube Size: 6.35 x 0.35 mm	US $ 3.50
A789 S31803 Tube Size: 25.4 x 1.0 mm	US $ 10.00

Note:
Mill test certificates will be issued according to EN10204.3.
All tubes shall be supplied as per applicable ASTM A789 /A789M Specification.

 

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