SS 321 Seamless Tubes Manufacturer and Supplier in Thailand

Stainless Steel 321 Seamless Tubes is a titanium-stabilized austenitic tube known for their excellent resistance to intergranular corrosion and superior high-temperature strength. These tubes are ideal for applications requiring stability at elevated temperatures, such as in heat exchangers, aerospace systems, and petrochemical industries. Thaida, a trusted stainless steel seamless tube manufacturer based in Chon Buri, Thailand, offers high-quality seamless tubing solutions backed by years of pipe manufacturing experience. We specialise in producing tubes in various sizes and grades, ensuring superior surface finish and dimensional accuracy. All tubes are made using advanced hot extrusion and cold drawing processes, followed by solution annealing. We also offer services like custom cut-to-length supply and bulk order fulfillment, ensuring quality, precision, and timely delivery tailored to your project requirements.

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Product Overview Of Stainless Steel 321 Seamless Tubes

Stainless Steel 321 seamless tubes are titanium-stabilized stainless steel tubes known for withstanding exposure to high temperatures. Made from austenitic stainless steel, these tubes are ideal for environments where temperatures reach up to 1,292°F. The addition of titanium helps stabilize the steel and prevent cracking and corrosion in heat-affected areas. This seamless tubing is available in various standard sizes and thicknesses, including 1-1/4″ to 2-1/2″, with options like 1-1/2″ Schedule 10 Wall, 36 inches. They meet global standards such as ASTM A312 and ASME SA312. Common schedules include Sch 10, Sch 40 and more, depending on the required pressure and application. These offer high mechanical strength, excellent formability and good weldability. Physically, they have a high melting point, good thermal conductivity and oxidation resistance, which makes AMS 5557 tubing reliable in extreme service conditions. 

Why Choose Our Stainless Steel 321 Seamless Tubes?

Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd. is a reliable stockholder and dealer of stainless steel 321 seamless tubes, providing consistent quality at competitive prices. We maintain a ready stock of various sizes and specifications to ensure quick delivery. Known for our dependable service and positive reviews, customers buy from us with confidence both locally and from nearby regions.

Competitive Pricing

Competitive Pricing

Global Exports Expertise

Global Exports Expertise

Large Inventory & Fast Dispatch

Large Inventory & Fast Dispatch

Custom Sizes & Finishes

Custom Sizes & Finishes

Industry Certifications & Compliance

Industry Certifications & Compliance

Long service life in harsh conditions

Advanced Production Technology

After-Sales Support, Service- Technical Support

After-Sales Support, Service- Technical Support

In-House Testing & Full Traceability

In-House Testing & Full Traceability

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UNS S32100 321 Seamless Tubes Specifications

The key details like ASTM A312, ASME SA312 standards, size range, forms, ends and packaging options of these tubes are mentioned.
Specifications ASTM A/ASME SA213
Sizes (Seamless) 1/2" NB - 24" NB
Wall Thickness available Schedule 5S - Schedule XXS (heavier on request)
Other Materials Testing NACE MR0175, H2 SERVICE, OXYGEN SERVICE, CRYO SERVICE, etc.
Dimensions All Pipes are manufactured and inspected/tested to the relevant standards including ASTM, ASME and API etc.

Size Of Stainless Steel 321 Seamless Tubes

This chart provides outer diameter and wall thickness to help select the right tube size for your needs.

NB SIZES SCH 5 SCH 10 SCH 40 SCH 80 SCH 160
1/8″ √ √ √ √ √
1/4″ √ √ √ √ √
3/8″ √ √ √ √ √
1/2″ √ √ √ √ √
3/4″ √ √ √ √ √
1″ √ √ √ √ √
1 1/4″ √ √ √ √ √
1 1/2″ √ √ √ √ √
2″ √ √ √ √ √
2 1/2″ √ √ √ √ √
3″ √ √ √ √ √
4″ √ √ √ √ √
5″ √ √ √ √ √
6″ √ √ √ √ √

The table includes the percentage of key elements like chromium, nickel, titanium and carbon that define its high-temperature performance.

Grade C Mn Si P S Cr Ni Mo Ti
321 ≤0.08 ≤2.00 ≤1.00 ≤0.045 ≤0.03 17.00-19.00 9.00-12.00 - /
The essential mechanical values such as tensile strength, yield strength, elongation percentage and hardness ratings of these tubes.
Grade Tensile Strength (MPa) min Yield Strength 0.2% Proof (MPa) min Elongation (% in 50mm) min Hardness
Rockwell B (HR B) max Brinell (HB) max
321 515 205 40 95 217
The table includes density, specific heat capacity and thermal conductivity of these tubes useful for high-temperature applications.
Grade Density (kg/m3) Elastic Modulus (GPa) Mean Coefficient of Thermal Expansion (m/m/°C) Thermal Conductivity (W/m.K)
0-100°C 0-315°C 0-538°C at 100°C at 500°C
321 8027 193 16.6 17.2 18.6 16.1 22.2
The range of outer diameters and their tolerances are given below to ensure dimensional accuracy for different requirements.
Nominal
Pipe
Size
(inches)		 Outside
Diameter		 Schedule
5S 10S 40S 80S
(mm) (inches) Wall Thickness and Weight
mm
(in)		 kg/m mm
(in)		 kg/m mm
(in)		 kg/m mm
(in)		 kg/m
1/8
10.3
0.405
-
-
1.25
(0.049)
0.28
1.73
(0.068)
0.37
2.42
(0.095)
0.47
1/4
13.7
0.540
-
-
1.66
(0.065)
0.49
2.24
(0.088)
0.63
3.03
(0.119)
0.80
3/8
17.2
0.675
-
-
1.66
(0.065)
0.63
2.32
(0.091)
0.85
3.20
(0.126)
1.10
1/2
21.3
0.840
1.65
(0.065)
0.81
2.11
(0.083)
1.00
2.77
(0.109)
1.27
3.74
(0.147)
1.62
3/4
26.7
1.050
1.65
(0.065)
1.02
2.11
(0.083)
1.28
2.87
(0.113)
1.68
3.92
(0.154)
2.20
1
33.4
1.315
1.65
(0.065)
1.30
2.77
(0.109)
2.09
3.38
(0.133)
2.50
4.55
(0.179)
3.24
1 1/4
42.2
1.660
1.65
(0.065)
1.66
2.77
(0.109)
2.69
3.56
(0.140)
3.39
4.86
(0.191)
4.47
1 1/2
48.3
1.900
1.65
(0.065)
1.91
2.77
(0.109)
3.11
3.69
(0.145)
4.06
5.08
(0.200)
5.41
2
60.3
2.375
1.65
(0.065)
2.40
2.77
(0.109)
3.93
3.92
(0.154)
5.45
5.54
(0.218)
7.49
2 1/2
73.0
2.875
2.11
(0.083)
3.69
3.05
(0.120)
5.26
5.16
(0.203)
8.64
7.01
(0.276)
11.4
3
88.9
3.500
2.11
(0.083)
4.52
3.05
(0.120)
6.46
5.49
(0.216)
11.3
7.62
(0.300)
15.3
3 1/2
101.6
4.000
2.11
(0.083)
5.18
3.05
(0.120)
7.41
5.74
(0.226)
13.6
8.08
(0.318)
18.6
4
114.3
4.500
2.11
(0.083)
5.84
3.05
(0.120)
8.37
6.02
(0.237)
16.1
8.56
(0.337)
22.3
5
141.3
5.563
2.77
(0.109)
9.46
3.41
(0.134)
11.6
6.56
(0.258)
21.8
9.53
(0.375)
31.0
6
168.3
6.625
2.77
(0.109)
11.3
3.41
(0.134)
13.9
7.12
(0.280)
28.3
10.98
(0.432)
42.6
8
219.1
8.625
2.77
(0.109)
14.8
3.76
(0.148)
20.0
8.18
(0.322)
42.5
12.70
(0.500)
64.6
10
273.1
10.750
3.41
(0.134)
22.7
4.20
(0.165)
27.8
9.28
(0.365)
60.4
12.70
(0.500)
81.5
12
323.9
12.750
3.97
(0.156)
31.3
4.58
(0.180)
36.1
9.53
(0.375)
73.9
12.70
(0.500)
97.4

Stainless Steel 321 Seamless Tubes Manufacturing Process

Stainless steel 321 seamless tube manufacturing involves a five-stage process to ensure high quality each tube meets industry standards for strength, durability and a flawless finish.
Stainless Steel Seamless Tubes Manufacturing Process

1. Raw Material Selection
High-quality stainless steel billets and strips are carefully selected for superior strength and corrosion resistance.

2. Tubes Formation
The selected raw material is formed into tubes using seamless extrusion methods, depending on the application.

3. Heat Treatment
Tubes undergo required controlled heat treatment to enhance mechanical properties and relieve internal stresses.

4. Cold Working and Finishing
After heat treatment, tube are cold-worked for better surface finish, dimensional accuracy and improved strength.

5. Quality Control and Testing
Every tube is thoroughly inspected and tested to ensure it meets international quality standards for performance and reliability.

Application Of Stainless Steel 321 Seamless Tubes

Stainless steel seamless 321 tubes are primarily used in the aerospace industry for high-temperature fluid and gas transport systems, making it the leading sector for their application. These tubes are used in aircraft exhaust manifolds, jet engine components, and afterburner assemblies due to their excellent heat resistance and stability. In the chemical and power generation industries, they are used in heat exchangers, boiler tubes, and process piping where resistance to oxidation and intergranular corrosion is critical. Their reliability in extreme thermal environments makes them a preferred choice for long-term performance in demanding applications.

Oil and Gas Industry

Chemical and Petrochemical Industry

Food and Beverage Industry

Pharmaceutical & Biotechnology

Aerospace & Defense

Automotive and Transportation

Construction and Architecture

Marine & Shipbuilding

Power Generation & Heat Exchange

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FAQ's

What is 321 stainless steel tube used for?

321 stainless steel tubes are primarily used in high-temperature service applications. Their main use is in environments exposed to temperatures between 800°F to 1500°F (427°C to 816°C) This includes aircraft exhaust systems, boiler and furnace components, and heat exchangers where stability after welding is crucial.

321 stainless steel tubes resist rust very well due to their high chromium content, but they are not entirely corrosion-proof. Like other stainless steels, they rely on a passive chromium oxide layer for protection. They handle general corrosive conditions well but can still suffer pitting or crevice corrosion in severe chloride or stagnant water environments.

To weld 321 stainless steel tube, use standard techniques like Gas Tungsten Arc Welding (GTAW) or Shielded Metal Arc Welding (SMAW). The grade’s titanium stabilization prevents weld decay, meaning post-weld heat treatment is not usually required. Using a matching filler metal, typically E347 or ER347, is recommended to maintain the corrosion resistance of the welded joint.

The difference lies in their primary application and composition. 310 stainless steel is a high-chromium, high-nickel alloy used for continuous service at very high temperatures often above 2000 °F (1093 °C). 321 stainless steel is optimized for the intermittent high-temperature range 800 °F to 1500 °F where its titanium stabilization prevents chromium carbide precipitation after welding.

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