Information on 321/321H stainless steel seamless pipes
Information on 321/321H stainless steel seamless pipes
321/321H stainless steel seamless pipe is a titanium-stabilized austenitic stainless steel alloy, renowned for its excellent high-temperature strength and resistance to intergranular corrosion. The "H" grade (321H) is a high-carbon version with even higher creep resistance and high-temperature strength.
What are the specifications of 316 stainless steel seamless pipe?
The minimum design tensile strength of 316 stainless steel pipe is 515 MPa, and the minimum yield strength is 200 MPa. Its density is 8000 kg/m³. The standard wall thickness range for these pipes is 0.5 mm to 6.35 mm. 316 stainless steel seamless pipe is manufactured using either fillet weld-free or welded processes.
About SS 321/321H Seamless Steel Pipe
SS 321/321H seamless steel pipe is manufactured using an extrusion process from solid steel billets. It has no internal welds or joints. Although shorter in length, it is continuous. These pipes can be used with extremely dilute acids at nominal temperatures and with pure phosphoric acid at lower temperatures. SS 321/321H seamless steel pipe exhibits excellent resistance to polythiosulfate stress corrosion cracking in hydrocarbon-containing environments.
In our production facilities, all steel pipes produced undergo material evaluation testing to ensure product reliability. To prevent damage, we supply stainless steel pipes in large bundles.
Stainless Steel 321/321H Seamless Pipe Specification
| Specifications | ASTM A312/ ASME SA312 |
| Seamless Pipes | 1 / 2" NB - 16" NB |
| Outside Diameter | 6.00 mm OD up to 914.4 mm OD, Sizes up to 24" NB available Ex-stock, OD Size Steel Tubes available Ex-stock |
| Thickness Range | 0.3mm – 50 mm, SCH 5, SCH10, SCH 40, SCH 80, SCH 80S, SCH 160, SCH XXS, SCH XS |
| Type | Seamless |
| Form | Round Pipes, Square Pipes, Rectangular Pipes |
| Length | Single Random, Double Random & Required Length |
| End | Plain End, Beveled End, Treaded |
| Outside Finish | 2B, No.4, No.1, No.8 Mirror Finish for Stainless Steel Pipes, Finish as per customer Requirements |
| Delivery Condition | Annealed and Pickled, Polished, Bright Annealed, Cold Drawn |
Stainless Steel UNS S32100/S32109 Seamless Pipes Equivalent Grades
| STANDARD | UNS | WERKSTOFF NR. | EN | JIS |
| SS 321 | S32100 | 1.4541 | X6CrNiTi18-10 | SUS 321 |
| SS 321H | S32109 | 1.4878 | X12CrNiTi18-9 | SUS 321H |
321/321H Stainless Steel Seamless Pipes Chemical Composition
| Grade | C | Mn | Si | P | S | Cr | N | Ni | Ti |
| SS 321 | 0.08 max | 2.0 max | 1.0 max | 0.045 max | 0.030 max | 17.00 - 19.00 | 0.10 max | 9.00 - 12.00 | 5(C+N) – 0.70 max |
| SS 321H | 0.04 – 0.10 | 2.0 max | 1.0 max | 0.045 max | 0.030 max | 17.00 - 19.00 | 0.10 max | 9.00 – 12.00 | 4(C+N) – 0.70 max |
Key Characteristics of 321/321H Seamless Steel Pipe
High Temperature Resistance: Exhibits excellent oxidation and scaling resistance at temperatures up to 816°C (1500°F). The 321H grade is suitable for even higher temperature applications, typically exceeding 537°C (1000°F).
Seamless Structure: Seamless steel pipes are integrally formed from solid steel billets without internal welds, offering superior structural integrity, strength, and high-pressure resistance compared to welded steel pipes.
Corrosion Resistance: Overall corrosion resistance is comparable to 304 stainless steel, but its main advantage lies in its resistance to polythiosulfate stress corrosion cracking and intergranular corrosion in the high-temperature affected zone. Its performance is poor in strong chloride or sulfuric acid solutions.
Physical Properties: Non-magnetic in the annealed state and cannot be hardened by heat treatment, only by cold working.
Common Applications of 321/321H Seamless Steel Pipe
Due to its unique properties, 321/321H seamless steel pipes are commonly used in harsh high-temperature environments.
Aerospace: Piston engine manifolds and jet engine components.
Automotive: Turbocharging manifolds and exhaust systems.
Industrial processing: Heat exchangers, furnace components, boiler piping, radiant superheaters, and bellows.
Petroleum refining: Equipment used in polythiosulfate processes.
FAQ
Q: What is the difference between SS 321 and 321H?
A: The main difference between SS 321 and 321H lies in their carbon content: SS 321 has a maximum carbon content of 0.08%, while 321H ranges from 0.04% to 0.10%. Their compositions are similar.
Q: What is 321 stainless steel pipe?
A: 321 stainless steel is a heat-resistant steel known for its excellent corrosion resistance and high-temperature strength. This austenitic alloy maintains its toughness and overall strength even at low temperatures, making it suitable for a wide range of high-temperature applications.
Q: What is type 321 stainless steel?
A: 321 stainless steel is a titanium-stabilized austenitic stainless steel, and its corrosion resistance is similar to that of 304/304L stainless steel.
