321 / 321H Stainless Steel Pipe
321/321H stainless steel pipe is a titanium-stabilized austenitic stainless steel known for its exceptional high-temperature resistance and resistance to intergranular corrosion.It is an improved version of 304 stainless steel pipe;the addition of titanium allows it to maintain good chemical stability within the carbide precipitation temperature range of 427°C to 816°C (800°F to 1500°F).
Heat Treatment of 321 / 321H Stainless Steel Pipe
Solution Annealing
- Temperature:
Heat to 950°C – 1120°C (1750℉ – 2050 ℉). - Process:
Hold for a time dependent on thickness,followed by rapid cooling (water quenching or forced air) to prevent carbide precipitation. - Purpose:
Dissolves any precipitated carbides back into the austenite matrix.
Stress Relieving
- Temperature:
700℃ (1290℉) for 1 to 2 hours. - Caution:
Prolonged heating in the 425℃ to 815℃ range can slightly reduce corrosion resistance if the material was not properly stabilized beforehand.
Stabilization Treatment
- Temperature:
845℃ to 900℃(1550℉ to 1650℉). - Process:
Hold at this temperature for several hours (typically 2–4 hours). - Purpose:
This allows the Titanium to react with any remaining carbon to form Titanium Carbides (TiC).By “tying up” the carbon with titanium,it prevents the formation of chromium carbides,ensuring maximum resistance to Intergranular Corrosion (IGC) in severe service conditions.
Specific Requirements for 321H
- Grain Size:
To meet 321H specifications (ASTM A312),the solution annealing temperature must be high enough (typically above 1040℃) to ensure a coarse grain size (ASTM No. 7 or coarser). - Mechanical Strength:
The higher carbon content (0.04 – 0.10%) requires precise temperature control to balance strength and ductility at temperatures exceeding 537℃ (1000℉).
321 / 321H Stainless Steel Pipe Chemical Composition
| Element (%) | 321 (S32100) | 321H (S32109) |
|---|---|---|
| C | ≤ 0.08% | 0.04% – 0.10% |
| Mn | ≤ 2.00% | ≤ 2.00% |
| P | ≤ 0.045% | ≤ 0.045% |
| S | ≤ 0.030% | ≤ 0.030% |
| Si | ≤ 1.00% | ≤ 1.00% |
| Cr | 17.0% – 19.0% | 17.0% – 19.0% |
| Ni | 9.0% – 12.0% | 9.0% – 12.0% |
| Ti | 5 × (C + N) to 0.70% | 4 × C to 0.70% |
| N | ≤ 0.10% | ≤ 0.10% |
321 / 321H Stainless Steel Pipe Mechanical Properties
| Property | 321 (S32100) | 321H (S32109) |
|---|---|---|
| Tensile Strength, min. | ≥ 515 MPa | ≥ 515 MPa |
| Yield Strength (0.2% Offset), min. | ≥ 205 MPa | ≥ 205 MPa |
| Elongation (in 2 in. or 50mm), min. | ≥ 35% | ≥ 35% |
| Hardness, max. | ≤ 192 HBW | ≤ 192 HBW |
What We Do
- Plate
- Sheet
- Forgings
- Round Bar
- Flange
- Pipes
- Fittings
- Customized
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Manufacturing Standards for 321 / 321H Stainless Steel Pipe
- ASTM A312 / ASME SA312:
Covers seamless,welded,and heavily cold-worked austenitic stainless steel tubes.Primarily used for high-temperature and general corrosive service. - ASTM A213 / ASME SA213:
Covers seamless ferritic and austenitic alloy steel boiler tubes, superheater tubes,and heat exchanger tubes.Imposes stricter requirements on dimensional tolerances and mechanical properties. - ASTM A269:
Seamless and welded austenitic stainless steel instrument and fluid tubes for general purposes. - ASTM A358 / ASME SA358:
Electric fusion-welded (EFW) austenitic stainless steel tubes,suitable for high-temperature and high-pressure applications (typically large-diameter tubes). - ASTM A409:
Welded large-diameter,thin-walled tubes for corrosive or high-temperature service.
Features
- Titanium Stabilization
- Intergranular Corrosion Resistance
- High Creep Strength
- Oxidation Resistance
- Formability & Weldability
Applications
- Aerospace
- Petro-Chemical
- Power Generation
- Pollution Control
- Industrial Furnaces
Our Capabilities Regarding 321/321H Stainless Steel Pipe
Manufacturing Excellence
Manufactured using hot extrusion or cold drawing/cold rolling processes to ensure the integrity of the pipe body under high-pressure conditions,our seamless pipes comply with ASTM A312/A213 standards.We offer welded pipes—including those produced via automatic welding (TIG/plasma welding) and electric fusion welding (EFW,ASTM A358)—to meet the requirements of large-diameter engineering projects.
Kaysuns is equipped with advanced continuous solution annealing furnaces and strictly adheres to solution annealing at temperatures above 1040°C.We provide precise stabilization heat treatment for 321H to ensure the full formation of titanium carbides.
Capable of producing 321H-grade steel tubes that meet the grain size requirements of ASTM No. 7 or coarser,ensuring creep strength at ultra-high temperatures.
Supply & Logistics
| Product | Stainless Steel Pipes and tubes |
| Grade | 321 | 1.4541 ，321H | 1.4878 |
| Dimension | 1/2” ~ 24” for smls, 6” ~ 104” for EFW pipe The dimensions of stainless steel pipes comply with ASME B36.19/B36.10 standards. |
| Schedule | SCH10S, SCH20, SCH30, SCH40, STD, SCH80, XS, SCH60, SCH80, SCH120, SCH140, SCH160, XXS |
| Type | Seamless / Welded |
| Manfaucturing Craft | Cold Drawn,Cold Rolled (ERW/EFW for welded) |
| Pipe End | Plain End, Beveled End, Treaded |
| Delivery Condtions | Solution Annealing, Bright Annealing |
Our products comply with international standards (ASTM/ASME,EN 1.4541/1.4878,DIN,JIS,GOST),making them suitable for bidding on major global EPC projects.We maintain a stock of common 321 and 321H specifications to shorten lead times,while also offering customized production services for special lengths or tolerance requirements.
Quality Assurance
Each batch of products undergoes testing in our physical and chemical laboratory and is accompanied by an MTC,in compliance with EN 10204,Section 3.1 or 3.2.
100% of products pass eddy current testing (ET),ultrasonic testing (UT),or hydrostatic testing.
Upon customer request,we can perform intergranular corrosion testing in accordance with ASTM A262 Practice E to verify the effectiveness of titanium stabilization.
100% of products pass eddy current testing (ET),ultrasonic testing (UT),or hydrostatic testing.
Upon customer request,we can perform intergranular corrosion testing in accordance with ASTM A262 Practice E to verify the effectiveness of titanium stabilization.
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Get In Touch
- RM901 No.22 Tangjiaqiao Road Wenzhou China
- +86 577 8551 1171
- [email protected]
- https://www.kaysuns.com/
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