What is 321H material?

321H stainless steel is a high-carbon, titanium-stabilized austenitic alloy designed for excellent high-temperature performance. Its increased carbon content enhances strength and creep resistance above 1000°F (537°C), while titanium stabilization prevents intergranular corrosion during exposure to sensitization temperatures between 800°F and 1500°F. These properties make it well-suited for demanding applications such as aircraft exhaust systems, furnace components, and other high-heat industrial environments.

What is the temperature range for ss321h tube?

SS321H tubes are designed for high-temperature service, typically operating between 427°C and 816°C (800°F to 1500°F), with excellent resistance to carbide precipitation and intergranular corrosion due to titanium stabilization. It offers strong oxidation resistance up to 925°C (1697°F) in continuous service and retains good toughness even at cryogenic temperatures. The higher carbon content enhances strength and creep resistance above 538°C (1000°F), making these tubes ideal for aircraft exhaust systems, manifolds, and high-temperature chemical processing equipment.

What is the composition of 321H stainless steel tube?

321H stainless steel tube is an austenitic alloy primarily composed of chromium (17.0–19.0%) and nickel (9.0–12.0%), with titanium (minimum 0.70%) added to enhance corrosion resistance and stability at high temperatures. It also contains 0.04–0.10% carbon, up to 2.0% manganese, 1.0% silicon, 0.045% phosphorus, and 0.03% sulfur, with iron making up the balance. This composition provides excellent strength, thermal stability, and resistance to carbide precipitation.

Stainless Steel 321H Seamless Tubes

Name: Stainless Steel 321H Seamless Tubes
Brand: Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd.

Stainless Steel 321H Seamless Tubes is a high-carbon, titanium-stabilized austenitic stainless steel tubes designed for enhanced strength and performance at elevated temperatures. Ideal for heat-intensive applications, these tubes are commonly used in heat exchangers, pressure vessels, and high-temperature chemical processing systems. Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd., based in Chon Buri, is a trusted manufacturer of 321H seamless tubes, supported by years of tube manufacturing expertise. Our tubes meet ASTM A312 and ASME SA312 standards, ensuring superior durability and performance. With a variety of sizes, thicknesses and schedules like SCH 10, these UNS S32109 tubes are available in different finishes, including pickled and annealed. Stainless steel 321H differs from standard 321 steel with its higher carbon content, enhancing its strength and resistance to high temperatures. Our strict manufacturing process and commitment to quality are backed by third-party inspections and certifications.

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Product Overview: Stainless Steel 321H Seamless Tubes

Stainless Steel 321H Seamless Tubes is a titanium-stabilized austenitic stainless steel tube designed for high-temperature applications. It offers excellent strength and resistance to carbide precipitation which makes it suitable for continuous service in the temperature range of 427-816°C (800-1500°F). This tube is especially useful in environments where corrosion resistance and long-term durability are critical. These tubes are available in a wide range of sizes from 1/8” NB to 24” NB or 1/4” OD to 24” OD, with varying wall thicknesses and schedules like SCH 10, SCH 40 and more. SS 321H tubes are commonly used in boilers, radiant superheaters, exhaust systems, refinery piping and other general purpose industrial settings. These tubes are built to deliver exceptional value and reliability.

Why Choose Our Stainless Steel 321H Seamless Tubes?

Our Stainless Steel 321H Seamless Tubes are the ideal choice for industries that demand superior strength and resistance to high temperatures. We maintain strict quality assurance across all production stages to ensure each tube delivers outstanding performance in demanding conditions. Available in a variety of dimensions and finishes, our tubes can be customized to your required lengths and supplied in bulk. Whether you’re involved in petrochemical processing, thermal power generation, or high-pressure applications, Thaida’s 321H tubes provide long-lasting reliability and meet global industry standards.

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ASTM A269 TP321H Seamless Tubes Specifications

This table outlines standard codes, size range, length, type, ends, forms and applications for DIN 1.4878 / UNS S32109 tubes.

Specifications	ASTM A213 / ASTM SA213
Tube Range	6.35 mm OD To 101.6 mm OD
Guage	25 SWG - 10 SWG
Outer Diameter	3.00 mm - 219.10 mm
Wall Thickness	0.40 mm - 12.70 mm
Schedules	5, 10S, 10, 30, 40S, 40, 80, 80S, XS, 160, XXH
Length	Upto 30 meters, Custom Cut Lengths
Types	Round, Square, Rectangle, Coil, "U" Shape, Hydraulic & Honed Tubes

Chemical Composition of TP 321H Stainless Steel Seamless Tubes

The percentage of elements like chromium, nickel, carbon and others that define the alloy’s composition and stability.

Grade	C	Mn	Si	P	S	Cr	Ni	Mo	Ti
321H	0.04-1.00	≤2.00	≤1.00	≤0.045	≤0.03	17.00-19.00	9.00-12.00	-	4*(C+N)-0.70

321H Seamless Tubes Mechanical Properties

The key mechanical values include tensile strength, yield strength, elongation and hardness are mentioned for reliable performance.

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
321H	515	205	40		95	217

Grade Specifications of UNS S32109 321H Seamless Tubes

The table details various grade-related specifications including dimensions, tolerance levels and applicable manufacturing standards.

Grade	UNS No	Old British		Euronorm		Swedish SS	Japanese JIS
Grade	UNS No	BS	En	No	Name	Swedish SS	Japanese JIS
321H	S32109	321S51	-	1.4878	X6CrNiTi18-10	-	SUS 321H

Physical Properties of Stainless Steel 321H Seamless Tubes

The essential physical characteristics like density, thermal conductivity and specific heat capacity of these seamless tubes are mentioned below.

Grade	Density (kg/m3)	Elastic Modulus (GPa)	Mean Coefficient of Thermal Expansion (m/m/°C)			Thermal Conductivity (W/m·K)		Specific Heat 0–100°C (J/kg·K)	Electrical Resistivity (n·m)
Grade	Density (kg/m3)	Elastic Modulus (GPa)	0–100°C	0–315°C	0–538°C	at 100°C	at 500°C	Specific Heat 0–100°C (J/kg·K)	Electrical Resistivity (n·m)
321H	8027	193	16.6	17.2	18.6	16.1	22.2	500	720

Stainless Steel 321H Seamless Tubes Manufacturing Process

Here’s a step-by-step process involved in manufacturing stainless steel 321H seamless tube that ensures strength, durability and a flawless finish in every tube, fully compliant with industry standards.

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 321H Seamless Tubes

Stainless steel tubes are most widely used in the power generation and petrochemical industries for high-temperature and high-pressure applications, making these sectors the top users of Stainless Steel 321H seamless tubes.

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

Are custom sizes available for Stainless Steel 321H Seamless Pipes?

Yes, custom sizes are available for Stainless Steel 321H seamless pipes, including specific lengths, diameters, and thicknesses. Suppliers can manufacture and supply both standard and non-standard dimensions to meet specific project requirements.

What industries commonly use Stainless Steel 321H Seamless Pipes?

Stainless Steel 321H Seamless Pipes are commonly used in the petrochemical, chemical, and oil and gas industries due to their excellent corrosion and high-temperature resistance. They are also widely used in the aerospace industry for exhaust systems, and in the power generation and pharmaceutical/food processing sectors.

Can Stainless Steel 321H Seamless Pipes handle high-pressure applications?

Stainless Steel 321H Seamless Pipes are well-suited for high-pressure and high-temperature applications due to their titanium-stabilized composition and high carbon content, which enhance strength and resistance to intergranular corrosion. Their seamless construction ensures superior structural integrity, making them ideal for demanding uses in petrochemical, aerospace, and power generation industries.

How should Stainless Steel 321H Seamless Pipes be handled to avoid damage?

Stainless Steel 321H seamless pipes require careful handling to prevent surface damage and contamination that could reduce their corrosion resistance. They should be lifted using nylon slings or padded clamps, stored in clean, dry, and segregated indoor areas, and kept elevated from the ground. Tools and workspaces must be dedicated to stainless steel to avoid cross-contamination, and regular inspection, cleaning, and passivation help maintain their protective surface and durability.

What is the difference between 321H and ss321?

Both Stainless Steel 321 and SS 321H are titanium-stabilized stainless steels designed for high-temperature and corrosive applications. The primary distinction is that 321H is the high-carbon version, offering superior strength and creep resistance at elevated temperatures, making it ideal for critical, high-stress environments like boiler components and industrial furnaces. In contrast, standard 321 has lower carbon, providing good strength and excellent weldability for general high-temperature uses such as aircraft exhaust systems and heat exchangers.

What is the temperature range for ss321h?

The normal temperature for SS321H is between 427°C and 816°C (800°F and 1500°F), with resistance to oxidation up to 925°C (1697°F) for continuous service. This grade is specifically engineered for high-temperature applications requiring enhanced creep resistance and strength.