UNS S32109|1.4878|TP321H Seamless Stainless Steel Pipe

Seamless Stainless Steel TP321H Pipes (UNS S32109 / W.Nr. 1.4878) are high-carbon austenitic solutions specifically engineered for superior creep-rupture strength and structural stability in extreme thermal environments. As a premier manufacturer based in Wenzhou, China, XinZhe produces high-integrity seamless piping that strictly adheres to ASTM A312, ASTM A213, and ASME SA312 international standards.

Distinguished by an optimized carbon content (0.04–0.10%) and strategic Titanium (Ti) stabilization, our TP321H tubing prevents sensitization and intergranular corrosion while maintaining enhanced mechanical properties at temperatures exceeding 538°C (1000°F). These pipes are indispensable for mission-critical applications in superheater coils, power plant boilers, and high-temperature refinery infrastructure. Through advanced cold-drawing and precise solution annealing, XinZhe guarantees a uniform grain structure and maximum durability for demanding thermal cycling conditions.

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What Is TP321H Seamless Stainless Steel Pipe?

Seamless Stainless Steel TP321H Pipe (UNS S32109) – High-Temperature Structural Solution

Seamless Stainless Steel TP321H Pipe (UNS S32109) is a titanium-stabilized austenitic stainless steel pipe designed for long-term service in elevated temperature environments, typically between 400°C and 815°C (750°F – 1500°F).

Key Features and Technical Advantages

As the high-carbon version of Grade 321 stainless steel, the “H” designation indicates a controlled carbon range of 0.04% – 0.10%, which significantly improves creep rupture strength and high-temperature load-bearing capacity.

Manufactured using a seamless process, the pipe features a uniform grain structure without longitudinal weld seams, ensuring superior reliability under high pressure, thermal cycling, and mechanical stress.

Enhanced Creep Rupture Strength

The increased carbon content improves resistance to creep deformation and rupture, making TP321H ideal for continuous high-temperature service in critical systems.

Titanium Stabilization (Anti-IGC Protection)

Titanium (Ti) binds with carbon to prevent chromium carbide precipitation, effectively eliminating intergranular corrosion (IGC) during welding and high-temperature exposure.

Excellent Oxidation and Scaling Resistance

TP321H offers stable performance in oxidizing environments up to 870°C (1600°F), ensuring long-term durability in harsh thermal conditions.

Seamless Structural Integrity

The absence of weld seams eliminates structural weak points, allowing the pipe to safely withstand high internal pressure and cyclic thermal stress.

Product Specifications and Data

To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for 321H stainless steel.

Chemical Composition

The composition of Stainless Steel 321H is carefully balanced to achieve its superior high-temperature strength and corrosion resistance.

Cr	Ni	P	S	Ti	Mn	Si	C
17.00 - 19.00	9.00 - 12.00	≤ 0.045	≤ 0.030	≥ 4×(C+N), ≤0.70	≤ 2.00	≤ 1.00	0.04 - 0.10

Note: The titanium content must be at least five times the carbon content to ensure stabilization.

Typical Mechanical Properties

Stainless Steel 321H is specifically designed to maintain its strength and shape in high-temperature, high-stress environments.

Tensile Strength	Yield Strength	Elongation	Hardness
≥ 515 MPa	≥ 205 MPa	≥ 35%	≤ 192 HBW

Typical Physical Properties

These physical properties highlight the material's ability to perform reliably under a wide range of conditions.

Density	Melting Point	Thermal Expansion	Thermal Conductivity	Modulus of Elasticity	Electrical Resistivity
8.0 g/cm³	1398 - 1454 °C	16.6 µm/m·°C (20-100°C)	16.3 W/m·K (20°C)	193 GPa	0.72 x 10⁻⁶ Ω·m (20°C)

Size Tolerance Chart

Standard	OD(D)	Tolerance （MM)		Thickness(S)	Tolerance(MM)	Length	Tolerance
	MM	Common	High	MM			MM
ASTM A312	D ≤48.3	+0.4/-0.8		10.3 ≤73	+20%-12.5%		+6.0/0
	48.3 ≤114.30	±0.8		88.9 ≤457.2,t/D ≤5%	+22.5%/-12.5%
	114.3 ≤219.1	+1.6/-0.8		88.9 ≤457.2,t/D >5%	+15%/-12.5%
	219.1 ≤457.2	+2.4/-0.8		D ≥508, t/D≤5%,SMLS	+22.5%/-12.5%
	457.2 ≤660.4	+3.2/-0.8		D ≥508, t/D>5%,SMLS	+15%/-12.5%
	660.4 ≤863.6	+4.0/-0.8		D ≥508, WELD	+17.5%/-12.5%
	863.6 ≤1219.2	+4.8/-0.8
JIS 3459 Hot-Finished Smls Pipe	D ＜50	±0.51		S ＜4	±0.5
	D ≥50	±1.0%		S ≥4	±12.5%
JIS 3459 Cold-Finished	D ＜30	±0.3		S ＜2	±0.2
	D ≥30	±1.0%		S ≥2	±10.0%
JIS G3463 Hot-Finished Smls Pipe	100	+0.4/-0.8		D ＜100， S	/	D	+7/0
				D ＜100， 2≤S	+40%/0	D	+10/0
				D ＜100， 2.4≤S	+35%/0
				D ＜100， 3.8≤S	+33%/0
				D ＜100， 4.6≤S	+28%/0	D	+13/0
	100 ≤D	+0.4/-1.2		D>100, S ＜2	/
	120 ≤D			D>100 ， 2≤S	/	D	+15/0
	160 ≤D	+0.4/-1.8		D>100 ， 2.4≤S	+35%/0
	200 ≤D	+0.4/-2.4		D>100 ， 3.8≤S	+33%/0	D>50,7	+10/0
				D>100 ， 4.6≤S	+28%/0
JIS G3463 Cold-finished		+0.4/-0.8		D	+0.4/0
	60 ≤D	±0.3		D ≥2.0	+20%/0	D>50,7	+13/0
	80 ≤D	±0.4		D ≥40	+22%/0
	100 ≤D	+0.4/-0.6
	120 ≤D	+0.4/-0.8				D>50,10M	+15/0
	160 ≤D	+0.4/-1.2
	200 ≤D	+0.4/-1.6
GB/T 14975 冷拔(扎)钢管	D	±0.3	±0.1	所有壁厚，普通级PA	+12.5%/-10%
	12.7		±0.15
	38.1	±0.4	±0.3
	88.9	±0.9%	±0.4
	139.7		±0.8	所有壁厚，高级PC	±10%
	203.2		±1.1
	219.1		±1.6
	D ≥323.9		±0.5%
GB/T 14976 冷拔(轧)钢管	6	±0.2	±0.15	S ≤3	±12%(10% /0 高级PC)
	10 ≤D	±0.2	±0.2
	30 ≤D	±0.2	±0.3	S>3	+12.5%/-10%(10%/0 高级PC)
	50 ≤D	0.85%	0.75%
	D>219	0.9%	0.8%	Smin, all	+22%/0(+20%/0 高级PC)

Manufacturing Standards and Compliance

TP321H seamless pipes are produced in accordance with major international standards, ensuring compatibility with global engineering projects:

ASTM A312 / ASME SA312 – Seamless austenitic stainless steel pipes
ASTM A213 / ASME SA213 – Boiler and heat exchanger tubes
EN 10216-5 – Seamless pressure tubes (European standard)
JIS G3459 / JIS G3463 – Japanese industrial standards

Typical Industrial Applications

Thanks to its superior high-temperature strength and corrosion resistance, TP321H is widely used in:

Aerospace Industry

Jet engine components, exhaust manifolds, and afterburner liners requiring thermal fatigue resistance.

Petrochemical & Refining

High-temperature piping systems in catalytic cracking units and hydrotreating processes.

Power Generation

Superheater tubes, boiler headers, and steam pipelines in supercritical and ultra-supercritical plants.

Environmental & Waste Treatment

Thermal oxidizers and recuperators handling high-temperature corrosive gases.

Quality Assurance, Testing & Certification

Each TP321H seamless pipe is delivered with full traceability and comprehensive inspection documentation:

Material Certification

EN 10204 3.1 / 3.2 Material Test Certificates (MTC)

Non-Destructive Testing (NDT)

100%Ultrasonic Testing (UT), 100%Eddy Current Testing (ET)

Material Verification

Positive Material Identification (PMI)

Corrosion Testing

Intergranular Corrosion (IGC) test per ASTM A262 Practice E

Mechanical Testing

Flattening, flaring, bend, and hardness tests

Third-Party Inspection

Inspection by SGS, BV, TUV, ABS, or other authorized bodies

Ready to Request a Quotation?

Send your TP321H Seamless Stainless Steel Pipe enquiry with grade, applicable ASTM/ASME standard and edition, OD × wall thickness, length, quantity, end finish, delivery destination and inspection documents — you will get a written quotation stating the specification and edition, delivery condition, documents included and lead time.

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