ASTM A213 TP321 Stainless Steel Seamless Heat Exchanger Tube

what is ASTM A213 TP321 Seamless Exchanger Tube ?

ASTM A213 TP321 is a seamless cold-drawn austenitic stainless steel tube intended for boilers, superheaters, heat exchangers and other high-temperature pressure service. The grade is stabilized with titanium, which combines with carbon to form stable carbides and prevents the precipitation of chromium carbides at grain boundaries during service in the range of about 427 – 816 °C. As a result, TP321 maintains its corrosion resistance and ductility under prolonged high-temperature exposure, where unstabilized grades such as 304 would be at risk of intergranular corrosion and sensitization.

 

ASTM A213 TP321 Seamless Exchanger Tube Specification 

Product Name	Stainless Steel 321/321H Heat Exchanger/Condenser Tubes Supplier, Manufacturer
Grade	•ASTM: TP321 / AISI 321 (UNS S32100) •GOST: 12X18H10T /12KH10N10T /12H18N10T /12Cr18Ni10Ti, 08X18H10T /08KN18N10T / 08H18N10T /08Cr18Ni10Ti , •EN: 1.4541 (X6CrNiTi18-10) •GB: 06Cr18Ni11Ti (S32168)
Standard	•ASTM A312,ASTM A213,ASTM A269,ASTM A511; •GOST 9940-81,GOST 9941-2022; •EN 10216-5; •GB/T 14976,GB13296
Specification	Outer Diameter Options: • Nominal Pipe Size (NPS): 1/8 in to 24 in (corresponding to actual OD per ASME B36.19M/B36.10M) • Mechanical Tubing OD: 6.35 mm to 108.0 mm (1/4 in to 4¼ in), per ASTM A269/A511 tolerances • Metric OD Range: 6.0 mm to 630.0 mm - covering both seamless pipe and precision tubing applications	Wall Thickness Options: • Standard pipe schedules: SCH 10S, SCH 40S, SCH 80S, SCH 160, and SCH XXS • Tubing wall gauges: 10 BWG, 12 BWG, 14 BWG, 16 BWG, 18 BWG, and 20 BWG • Metric thickness range: 0.89 mm to 80.0 mm (covering both seamless pipe and precision tubing applications)	Length Options: • Random lengths: 5–7 meters (typical range) • Fixed lengths: 6.0 m, 6.096 m (20 ft), 6.1 m, or 12.0 m - subject to mill capability and order volume • Custom lengths: available upon request, subject to technical feasibility and minimum order requirements
Pipe End	•Plain End (PE) •Beveled End (BE)
Surface Treatment Processes	• Acid Pickling • Mechanical Polishing • Bright Annealing (in Controlled Atmosphere) • Sand Blasting • Shot Blasting and Shot Peening
Quality Verification Tests and Inspections	• Tensile Strength • Reverse Bend Test • Flattening Test • Flare Test • Flange Test • Dimensional Inspection • Hydrostatic Pressure Test • Pneumatic Pressure Test • Hardness Test • Eddy Current Inspection • Intergranular Corrosion Resistance Test
Weight Per Meter	Stainless Steel Pipe Weight Calculation Formula=(OD-THK)*THK*0.02491 kg/m Example: For a 12KH18N10T pipe with OD = 45 mm and wall thickness (THK) = 4.5 mm, the weight is 4.540 kg/m.

 

ASTM A213 TP321 Seamless Tube Chemical Composition

Element	Content (wt%)
Carbon (C)	≤ 0.080
Silicon (Si)	≤ 0.75
Manganese (Mn)	≤ 2.00
Phosphorus (P)	≤ 0.045
Sulfur (S)	≤ 0.030
Chromium (Cr)	17.00 – 20.00
Nickel (Ni)	9.00 – 13.00
Titanium (Ti)	≥ 5 × C

 

Mechanical Properties

Property	Value
Tensile strength	≥ 515 MPa
Yield strength	≥ 205 MPa
Elongation	≥ 40%
Hardness	≤ 192 HBW

 

ASTM A213 TP321 Tube Equivalent Grades

System	Designation
ASTM / AISI	TP321
UNS	S32100
EN	1.4541 / X6CrNiTi18-10
ISO	X6CrNiTi18-10
JIS	SUS321
GOST	08X18H10T

 

High-Temperature Creep Data (UNS S32100)

For design at elevated temperature, creep resistance values are used. The values below are indicative minimum creep data published for the grade at three temperatures.

Property (MPa)	600 °C	700 °C	800 °C
Creep resistance Rz/1000	200	88	30
Creep resistance Rz/10000	142	48	15
Creep resistance Rz/100000	65	22	10
Creep limit R1/1000	110	45	15
Creep limit R1/10000	85	30	10

 

ASTM A213 TP321 Tube  Applications

Power industry: superheater and reheater tubes of power plant boilers, coping with steam temperatures above 600 °C.

Petrochemical and chemical industries: cracking furnace tubes and heat exchanger tubes handling high-temperature corrosive process fluids.

Heat exchange equipment: high-temperature heat exchangers and condensers, especially where there is a risk of intergranular corrosion.

Pressure equipment: key components of high-temperature pressure vessels and piping systems.

 

FAQ

What is the difference between TP321 and 304 tube?

TP321 is stabilized with titanium, so it resists chromium carbide precipitation in the 427 – 816 °C range and offers better stress crack resistance and ductility than 304 in high-temperature service. Grade 304 is not stabilized and may sensitize when held in this temperature range, which reduces corrosion resistance.

 

Why is titanium added to TP321?

Titanium combines preferentially with carbon to form stable titanium carbides. This keeps chromium in solid solution in the matrix, so chromium-depleted grain boundaries do not form during high-temperature exposure, preserving corrosion resistance and ductility.

 

What temperature range is TP321 suitable for?

TP321 is designed for service roughly in the range of 427 – 816 °C. The creep data show that load-bearing capacity decreases steadily above 600 °C, so design stresses at 700 °C and above must be based on creep strength, not room-temperature tensile properties.

 

Can TP321 tube be welded?

Yes. TP321 is readily welded with processes such as TIG and MIG. Filler metal of matching stabilized composition, such as ER321, is used so that the weld retains the same high-temperature characteristics as the base metal.

 

What surface finishes are available?

Common finishes are annealed and pickled, and bright annealed. Annealing after cold drawing restores the soft, corrosion-resistant condition, and pickling removes the oxide scale formed during heat treatment.

 

Is TP321 magnetic?

TP321 is austenitic and essentially non-magnetic in the annealed condition. As with other austenitic grades, cold working can induce slight magnetism that does not affect service performance.