ASTM A789 UNS S32750 Duplex Steel Tube for Heat Exchangers

If you are looking for high-performance heat exchanger tubes capable of withstanding seawater, high-chloride media, and high-pressure, high-temperature environments, we supply super duplex stainless steel tubes in accordance with ASTM A789 UNS S32750, including both seamless and welded options.

Our tubes are manufactured in compliance with ASTM A789 / ASME SA789 standards, using a solution annealing process at 1025–1125°C followed by rapid quenching to ensure optimal microstructure and performance.

Key specifications include:
Size range: Outer diameter (OD) 6–219.1 mm, wall thickness 0.5–20 mm.

UNS S32750 duplex tubes feature surface roughness :Ra ≤0.4 μm, tight dimensional tolerance within ±0.03 mm, and wall thickness tolerance of ±0.1 mm, with hardness ≤ 90 HRB, offering excellent formability and weldability.

Durability: Minimum tensile strength 800 MPa and yield strength 550 MPa. In aggressive environments, the service life is 2–3 times longer than 316L stainless steel tubes, significantly reducing maintenance costs and downtime.

We support custom sizes and lengths, and provide EN 10204 3.1/3.2 certification, along with PMI and NDT reports to ensure full traceability. Contact us today for more details and a competitive quotation!

 

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ASTM A789 UNS S32750 Duplex Steel Tube Applications

UNS S32750 heat exchanger tubes are widely used in oil & gas, petrochemical, seawater desalination, and chemical industries, particularly in shell-and-tube heat exchangers, condensers, and boiler feedwater systems.

 

ASTM A789 UNS S32750 Chemical Composition (%)

C	Mn	P	S	Si	Cr	Ni	Mo	N	Cu
≤ 0.030%	≤ 1.20%	≤ 0.035%	≤ 0.020%	≤ 0.8%	24.0 - 26.0%	6.0 - 8.0%	3 - 5%	0.24 - 0.32%	0.05%

 

Mechanical Properties

Tensile Strength	Yield Strength (0.2% offset)	Elongation	Heat Treatment	Hardness
≥800Mpa	≥550Mpa	≥15%	1025-1125℃ 1880-2060℉	Brinell HBW	Rockwell HRC	Vickers HV
				300	32	300

 

Heat Treatment Requires

Temperature	Quench
1880-2060 °F [1025-1125°C]	Rapid cooling in air or water

 

ASME SA 789 S32750 Welded Tubing Tolerance Chart

Straightness: .030" in 3"

Wall Tolerance +/- 10%

OUTER DIA INCHES	O.D. +/- INCHES	WALL THICKNESS INCHES
2" to 2-1/2" incl.	.012	.032 to .065
	.013	Over .065 to .109
	.014	Over .109 to .165
1/2" to 1" incl.	.005	.025 to .065
	.010	Over .065 to .134
1 to 1-1/2" incl.	.008	.025 to .065
	.010	Over .065 to .134
1-1/2" to 2" incl.	.010	.025 to .049
	.011	Over .049 to .083
	.012	Over .083 to .148
2-1/2" to 3-1/2" incl.	.014	.032 to .165
	.020	Over .165 to .220
3-1/2" to 5" incl.	.020	.083 to .165
	.025	Over .165 to .220

 

Weight Chart of ASTM A789 UNS S32750 Tube

Wall	Weight per	Dimensions	Wall	Weight per
(mm)	metre (kg)	(mm)	(mm)	metre (kg)
1.50	0.65	40 x40	3.00	3.75
1.20	0.44	40 x40	1.20	1.49
1.20	0.53	40 x40	2.00	2.45
1.50	0.55	40 x40	1.50	1.85
1.20	0.71	50 x50	1.50	2.32
2.00	1.19	50 x50	3.00	4.65
1.50	0.88	50 x50	2.00	3.08
1.50	1.14	60 x60	3.00	5.49
1.20	0.92	60 x60	2.00	3.71
2.00	1.49	70 x70	3.00	6.53
1.20	1.10	80 x80	3.00	7.53
3.00	2.20	80 x80	2.00	4.98
2.00	1.84	100 x 100	3.00	9.53
1.50	1.37	100 x 100	2.00	6.40

 

Order information:

Orders for product under this specification should include as following, so that we can provide you with a more accurate price.

Quantity (inch, metres, or number of lengths)

Type of product (seamless or welded tubes)

Grade

Size (outside diameter and average wall thickness, unless minimum wall thickness is specified)

Length (specific or random)

Special requirements

 

Quality Inspection

A professional supplier must provide data, not just promises. Ensure your PO (Purchase Order) requires the following:

Eddy Current Testing (ECT): Mandatory for detecting sub-surface defects in the tube wall.

Hydrostatic Testing: Usually 1.5x the design pressure to ensure zero-leakage performance.

Mill Test Certificate (MTC): Must be compliant with EN 10204 3.1 for full traceability.

Packing and Shipping:

Product Packaging:

All pipes are securely packed in wooden boxes or bundles with plastic caps to avoid damage during transit.

Each box/bundle is strapped with metallic strips for added strength.

Boxes/bundles are clearly labeled with product details and shipping marks for easy identification.

 

Shipping:

We offer worldwide shipping to any destination as per customer requirements.

We work with trusted shipping companies to ensure timely delivery and e handling of products.

Customers can choose from various shipping options including air, sea, or land transport.

Shipping costs may vary depending on the shipping location and mode of transport.