Seamless stainless steel pipe is a type of metal pipe without weld seams, made from stainless steel bars through piercing and then cold drawing or cold rolling. Commonly used materials include 304, 316L, and 310S. It is used in high-temperature, high-pressure applications, precision equipment, and machinery, and offers advantages such as acid and alkali resistance, pressure resistance, and high-temperature resistance.
Glory Steel‘s seamless stainless steel pipes comply with standards including GB/T 14976, ASTM A312, and JIS G3456, making them well-suited for use in petrochemical, nuclear power, and pharmaceutical industries. We offer a full range of sizes and accept customization, end finishing, punching, and other processing, as well as OEM/ODM services.
Specification
| Item | Stainless Steel Seamless Pipe |
| Material Grade | 304 / 304L / 316 / 316L / 321 / 310S / 2205 |
| Standard | ASTM A312, ASTM A213, ASTM A269, GB/T 14976 |
| Section Shape | Round |
| Structure Type | Seamless |
| Technique | Hot rolled + Cold Drawn / Cold Rolled |
| Surface Treatment | Pickling / Annealed / Bright Annealed / Polished |
| Outer Diameter | 6 mm – 630 mm (1/8″ – 24″) |
| Wall Thickness | 1.0 mm – 50 mm |
| Length | 1m – 12m or Custom Length |
| Certificates | ISO 9001, CE, SGS, MTC |
| Packing | Standard seaworthy packing |
Features
- Excellent corrosion resistance: Seamless 304/316 stainless steel pipe resists acid, alkali, and salt media, and is highly resistant to oxidation and rust.
- High mechanical properties: Due to its seamless construction, it possesses excellent pressure resistance. Simultaneously, its yield strength, tensile strength, and elongation are all very high.
- High and low temperature resistance: Stable for extended periods below 800℃, suitable for boilers, heat exchangers, and chemical industries. It exhibits good impact toughness in liquid nitrogen environments down to -196℃.
- Easy to process: Easy to cut, punch, and weld; precise dimensions; smooth and clean inner and outer walls; safe and non-toxic; long service life.
Application
- Petrochemical Industry – Pipelines for transporting corrosive liquids, petroleum cracking pipes, natural gas transmission pipes, and heat exchanger tube bundles.
- Food and Pharmaceutical Industry – Pipelines for transporting milk, juice, beer, and pharmaceuticals; precision tubing for workshop instruments and meters.
- Energy & Power & Automotive – Power plant boiler superheaters, solar thermal power generation piping systems, automotive parts.
- Environmental Protection & Water Treatment – Wastewater treatment plant purification pipes, seawater desalination equipment, etc.
- Construction & Decoration – Thin-walled stainless steel pipes for drinking water; also used in hot water systems; for safety and hygiene; handrails, supports, drainage, etc. in high-end environments.
Main materials and classifications
- 304/304L Seamless pipe: General-purpose austenitic stainless steel with good machinability and weldability; most widely used.
- 316/316L Seamless pipe: Contains molybdenum (Mo), therefore resistant to chloride corrosion from seawater and other sources; suitable for marine and chemical environments.
- 310S Seamless pipe: Heat-resistant stainless steel, withstands temperatures up to 1100℃; used in boiler tubes, heat treatment, and furnaces.
- 321 Seamless pipe: Contains titanium (Ti), resists intergranular corrosion at temperatures of 400-800℃; suitable for applications where post-weld annealing is not required.
- 2205 duplex stainless steel seamless pipe: High strength, resistant to stress corrosion; used in harsh corrosive environments such as seawater desalination.
Chemical composition and mechanical properties
Chemical composition
| Grade | C ≤ | Si ≤ | Mn ≤ | P ≤ | S ≤ | Cr | Ni | Mo |
| 304 | 0.08 | 1.00 | 2.00 | 0.045 | 0.030 | 18.0-20.0 | 8.0-11.0 | – |
| 304L | 0.03 | 1.00 | 2.00 | 0.045 | 0.030 | 18.0-20.0 | 8.0-12.0 | – |
| 316 | 0.08 | 1.00 | 2.00 | 0.045 | 0.030 | 16.0-18.5 | 10.0-14.0 | 2.0-3.0 |
| 316L | 0.03 | 1.00 | 2.00 | 0.045 | 0.030 | 16.0-18.5 | 10.0-14.0 | 2.0-3.0 |
Mechanical properties
| Grade | Tensile strength (MPa) | Yield strength (MPa) | Elongation (%) | Hardness (HB) |
| 304 | 515-1035 | 205 | 40 | ≤201 |
| 304L | 485-895 | 170 | 40 | ≤192 |
| 316 | 485-1035 | 170 | 40 | ≤201 |
| 316L | 485-895 | 150 | 40 | ≤192 |
| Applicable standards: ASTM A312, ASTM A213, ASTM A269, GB/T 14976 | ||||
Process
The process involves two core steps: hot rolling and cold drawing (cold rolling).
- Hot-rolled stainless steel seamless pipe: This is generally a semi-finished product, commonly known as a “raw pipe,” with a black oxide scale on the surface, and is not sold as a finished product.
- Cold-rolled stainless steel seamless pipe: This is a further processed finished product of hot-rolled stainless steel seamless pipe. The process includes:
- Stainless steel round bar → Heating → Piercing → Hot Rolling.
- Hot-rolled rough tube heading treatment → Annealing → Pickling → Oiling → Multi-pass cold drawing (cold rolling) → Heat treatment → Straightening and finishing → Dimensioning, hydrostatic testing, etc. → Finishing & Packing.
Surface treatment
Finishing includes: pickling for brightening, bright annealing, and internal and external polishing.
- Pickling: The surface has a matte silver-white finish, commonly known as “white-skinned pipe.” It is a low-cost and standard treatment for industrial pipes.
- Bright Annealing: The surface exhibits a natural, soft, and uniform metallic sheen, with enhanced corrosion resistance.
- Internal and External Polishing: Also known as mechanical polishing, this produces a mirror-like finish. Grades include 240#, 400#, and 600#, with higher grades resulting in a brighter finish.
Cold Rolling vs. Cold Drawing
- Cold rolling: Performed at room temperature, suitable for mass production, with high production efficiency and a wide thickness range, from foil to sheet.
- Cold drawing: Performed at room temperature, its advantages are high dimensional accuracy, and it can produce various cross-sections, such as hexagons and semicircles, with extremely small tolerances, making it suitable for precision applications.
Why Choose Glory Steel?
- Reliable Quality: Products conform to international standards such as ASTM A312, ASTM A269/A790, GB/T 14976, and JIS. All raw materials undergo rigorous chemical composition testing.
- Flexible Customization: A full range of stainless steel grades, covering various wall thicknesses and custom lengths from small-diameter precision tubes to large-diameter tubes.
- One-Stop Service: Providing processing services such as cutting, chamfering, tapping, punching, and polishing; OEM and ODM supported.
- Factory Prices: Factory direct sales, offering competitive wholesale prices, large stock of standard sizes, and timely delivery.
FAQs
As an ISO 9001 & CE certified manufacturer in Tianjin, China, Glory Steel produces high-quality seamless & welded stainless steel tubes in grades 304/316L/310S/321/2205. Our product line includes heat exchanger tubes, precision tubes, and large-diameter tubes. With our high-quality products and services, we export to over 120 countries.
