ASTM A511 Seamless Stainless Steel Mechanical Tubing
- Grade: MT 302, MT 303Se, MT 304, MT 304L, MT 305, MT 309S, MT 310S, MT 316, MT 316L, MT 317, MT 321, and MT 347, MT 403, MT 405, MT 410, MT 414, MT 416, MT 416 Se, MT 429/MT 430, MT 431, MT 440 A, MT 443, MT 446-1, MT 446-2, 29-4, and 29-4-2.
- Shapes: Round, Square, Rectangular
- Length: 3000-12000mm
- Type: Seamless
ASTM A511 Seamless Stainless Steel Mechanical Tubing
Golden Sunbird Metals supplies ASTM A511 seamless stainless steel mechanical tubing for applications that demand high strength, accurate dimensions, and dependable corrosion resistance. Manufactured by cold working or hot working, this seamless tubing is available in round, square, and rectangular shapes and is suitable for a broad range of mechanical and structural uses. The ASTM A511/A511M standard covers many stainless steel grades, including austenitic, ferritic, martensitic, and duplex options, giving customers flexible material choices for different performance requirements. With lengths from 3000 to 12000 mm, our seamless stainless steel mechanical tubing is well suited for machinery components, fabricated parts, industrial systems, and other demanding engineering projects. For customers seeking reliable, specification-compliant stainless steel tubing, Golden Sunbird Metals provides a quality solution built for consistency, durability, and long service life.
ASTM A511 Seamless Stainless Steel Mechanical Tubing Chemical Composition (wt.%)
Austenitic Stainless Steel
| Grade | C | Mn, max | P, max | S, max | Si, max | Ni | Cr | Mo | Ti |
| MT 302 | 0.08 to 0.20 | 2.00 | 0.04 | 0.03 | 1.00 | 8.0-10.0 | 17.0-19.0 | … | … |
| MT 303 | 0.15 max | 2.00 | 0.2 | 0.15 min | 1.00 | 8.0-10.0 | 17.0-19.0 | … | … |
| MT 303Se | 0.15 max | 2.00 | 0.04 | 0.03 | 1.00 | 8.0-11.0 | 17.0-19.0 | … | … |
| MT 304 | 0.08 max | 2.00 | 0.04 | 0.03 | 1.00 | 8.0-11.0 | 18.0-20.0 | … | … |
| MT 304L | 0.035 max | 2.00 | 0.04 | 0.03 | 1.00 | 8.0-13.0 | 18.0-20.0 | … | … |
| MT 305 | 0.12 | 2.00 | 0.04 | 0.03 | 1.00 | 10.0-13.0 | 17.0-19.0 | … | … |
| MT 309S | 0.08 max | 2.00 | 0.04 | 0.03 | 1.00 | 12.0-15.0 | 22.0-24.0 | … | … |
| MT 310S | 0.08 max | 2.00 | 0.045 | 0.035 | 1.50 | 19.0-22.0 | 24.0-26.0 | … | … |
| MT 316 | 0.08 max | 2.00 | 0.045 | 0.03 | 1.00 | 10.0-14.0 | 16.0-18.0 | 2.0-3.0 | … |
| MT 316L | 0.035 max | 2.00 | 0.045 | 0.03 | 1.00 | 10.0-15.0 | 16.0-18.0 | 2.0-3.0 | … |
| MT 317 | 0.08 max | 2.00 | 0.045 | 0.03 | 1.00 | 11.0-15.0 | 18.0-20.0 | 3.0-4.0 | … |
| MT 321 | 0.08 max | 2.00 | 0.045 | 0.03 | 1.00 | 9.0-13.0 | 17.0-20.0 | … | 5XC-0.60 |
| MT 347 | 0.08 max | 2.00 | 0.045 | 0.03 | 1.00 | 9.0-13.0 | 17.0-20.0 | … | 10XC-1.00 |
| N08820 | 0.070 max | 2.00 | 0.045 | 0.035 | 1.00 | 32.5-38.0 | 19.0-21.0 | 2.0-3.0 | … |
| N08367 | 0.030 max | 2.00 | 0.045 | 0.03 | 1.00 | 23.5-25.5 | 20.0-22.0 | 6.0-7.0 | … |
| N08800 | 0.10 max | 1.50 | 0.04 | 0.015 | 1.00 | 30.0-35.0 | 19.0-23.0 | … | … |
| N08810 | 0.10 max | 1.50 | 0.04 | 0.015 | 1.00 | 30.0-35.0 | 19.0-23.0 | … | … |
| N08811 | 0.10 max | 1.50 | 0.04 | 0.015 | 1.00 | 30.0-35.0 | 19.0-23.0 | … | … |
| N08904 | 0.020 max | 2.00 | 0.045 | 0.035 | 1.00 | 23.0-28.0 | 19.0-23.0 | 4.0-5.0 | … |
| N08925 | 0.020 max | 2.00 | 0.045 | 0.03 | 1.00 | 24.0-26.0 | 19.0-21.0 | 3.0-4.0 | … |
| N08926 | 0.020 max | 2.00 | 0.045 | 0.03 | 1.00 | 24.0-26.0 | 19.0-21.0 | 6.0-7.0 | … |
| S20910 | 0.06 max | 4.0-6.0 | 0.03 | 0.06 | 0.75 | 4.0-6.0 | 20.5-23.5 | 1.50-3.0 | 0.10-0.30 |
Ferritic and Martensitic Stainless Steel
| Grade | C, max | Mn, max | P, max | S, max | Si, max | Ni | Cr | Mo | Al | Cu | N |
| Martensitic | |||||||||||
| MT 403 | 0.15 | 1.00 | 0.040 | 0.030 | 1.00 | 0.50 max | 11.5-13.0 | 0.60 max | … | … | … |
| MT 410 | 0.15 | 1.00 | 0.040 | 0.030 | 1.00 | 0.50 max | 11.5-13.5 | … | … | … | … |
| MT 414 | 0.15 | 1.00 | 0.040 | 0.030 | 1.00 | 0.50 max | 11.5-13.5 | … | … | … | … |
| MT 416Se | 0.15 | 1.25 | 0.060 | 0.15 | 1.00 | … | 12.0-14.0 | … | … | … | … |
| MT 431 | 0.20 | 1.00 | 0.040 | 0.030 | 1.00 | 1.25-2.50 | 15.0-17.0 | … | … | … | … |
| MT 440A | 0.60 to 0.75 | 1.00 | 0.040 | 0.030 | 1.00 | … | 16.0-18.0 | 0.75 max | … | … | … |
| Ferritic | |||||||||||
| MT 405 | 0.08 | 1.00 | 0.040 | 0.030 | 1.00 | 0.50 max | 11.5-14.5 | … | 0.10-0.30 | … | … |
| MT 429 | 0.12 | 1.00 | 0.040 | 0.030 | 1.00 | 0.50 max | 14.0-16.0 | … | … | … | … |
| MT 430 | 0.12 | 1.00 | 0.040 | 0.030 | 1.00 | … | 16.0-18.0 | … | … | … | … |
| MT 443 | 0.08 | 1.00 | 0.040 | 0.030 | 1.00 | … | 18.0-23.0 | … | … | 0.90-1.25 | 0.25 max |
| MT 446-1 | 0.20 | 1.50 | 0.040 | 0.030 | 1.00 | … | 23.0-30.0 | … | … | 0.25 max | … |
| MT 446-2 | 0.20 | 1.50 | 0.040 | 0.030 | 1.00 | … | 23.0-30.0 | … | … | … | … |
| 29-4 | 0.10 | 1.00 | 0.030 | 0.025 | 1.00 | … | 28.0-30.0 | 3.5-4.2 | … | 0.15 max | 0.020 max |
| 29-4-2 | 0.0010 | 0.30 | 0.020 | 0.020 | 1.00 | … | 28.0-30.0 | 3.5-4.2 | … | 0.15 max | 0.020 max |
Austenitic-Ferritic Stainless Steel
| Grade | C, max | Mn, max | P, max | S, max | Si, max | Ni | Cr | Mo | N | Cu | Other Elements |
| S31260 | 0.030 | 1.00 | 0.030 | 0.030 | 0.75 | 5.5-7.5 | 24.0-26.0 | 2.5-3.5 | 0.10-0.30 | 0.20-0.80 | W 0.10-0.50 |
| S31803 | 0.030 | 2.00 | 0.030 | 0.020 | 1.00 | 4.5-6.5 | 21.0-23.0 | 2.5-3.5 | 0.08-0.20 | … | … |
| S32205 | 0.030 | 2.00 | 0.030 | 0.020 | 1.00 | 4.5-6.5 | 22.0-23.0 | 3.0-3.5 | 0.14-0.20 | … | … |
| S32506 | 0.030 | 1.00 | 0.030 | 0.020 | 0.75 | 5.5-7.5 | 24.0-26.0 | 1.5-3.0 | 0.05-0.25 | 0.50-1.50 | W 0.05-0.30 |
| S32507 | 0.030 | 1.50 | 0.035 | 0.020 | 0.80 | 8.5-9.5 | 24.0-26.0 | 3.0-4.5 | 0.24-0.32 | 0.50-1.00 | … |
| S32750 | 0.030 | 1.20 | 0.035 | 0.020 | 0.80 | 6.0-8.0 | 24.0-26.0 | 3.0-5.0 | 0.24-0.32 | … | … |
| S32760 | 0.030 | 1.00 | 0.030 | 0.010 | 1.00 | 6.0-8.0 | 24.0-26.0 | 3.0-4.0 | 0.20-0.30 | 0.50-1.00 | W 0.50-1.00 |
| S32900 | 0.08 | 2.00 | 0.040 | 0.030 | 1.00 | 3.0-5.0 | 23.0-28.0 | 1.0-2.0 | 0.05-0.20 | … | … |
| S32950 | 0.030 | 1.00 | 0.030 | 0.020 | 1.00 | 5.0-7.0 | 28.0-30.0 | 2.5-3.5 | 0.10-0.30 | 0.50-1.00 | W 2.1-2.5, Co 0.5-2.0 |
| S39274 | 0.030 | 1.00 | 0.030 | 0.020 | 0.75 | 6.0-8.0 | 24.0-26.0 | 2.5-3.5 | 0.24-0.32 | 0.50-1.00 | … |
| S39277 | 0.030 | 1.50 | 0.030 | 0.020 | 1.00 | 6.5-8.5 | 24.0-26.0 | 3.0-4.0 | 0.24-0.32 | 0.50-1.00 | … |
Features
- ASTM A511/A511M Seamless Stainless Steel Mechanical Tubing and Hollow Bar (austenitic, ferritic, martensitic, and duplex grades).
- True seamless construction produced by cold working or hot working, providing superior structural integrity without weld seams.
- Annealed delivery condition for optimal machinability, formability, ductility, and ease of fabrication.
- Excellent corrosion resistance across grades, suitable for indoor, outdoor, and mildly to moderately aggressive environments.
- Wide size range and multiple shapes (round, square, rectangular, special) supporting versatile mechanical and structural designs.
- Comprehensive testing including chemical analysis, tensile, intergranular corrosion, and metallographic examination for consistent quality.
- High dimensional accuracy and good straightness ideal for precision machining, boring, and heavy-wall hollow bar applications.
- Broad grade availability including high-temperature and specialized alloys for demanding mechanical performance.
- Reliable fabrication characteristics for cutting, machining, welding, and forming into custom components.
Technical Specifications
| Specification | Value |
| Standard | ASTM A511/A511M Seamless Stainless Steel Mechanical Tubing and Hollow Bar |
| Grade | MT 302, MT 303Se, MT 304, MT 304L, MT 305, MT 309S, MT 310S, MT 316, MT 316L, MT 317, MT 321, and MT 347, MT 403, MT 405, MT 410, MT 414, MT 416, MT 416 Se, MT 429/MT 430, MT 431, MT 440 A, MT 443, MT 446-1, MT 446-2, 29-4, and 29-4-2. |
| Manufacturing Process | Cold working or Hot working |
| Shape | Round, Square, Rectangular, or Special |
| Dimension | Round: OD 1″ – 12 3/4″ (3.18 – 313.8mm) WT: 2 – 100mm Square: 25 x 25 – 350 x 350mm x 2 – 20mm Rectangular: 25 x 38 – 250 x 300mm x 2 – 20mm |
| Length | 3000-12000mm |
| Delivery Condition | Annealed |
| Inspection Certificate | EN 10204 Type 3.1 (Mill Test Certificate), EN 10204 Type 3.2 (Witness Testing or 3rd Party Inspection) |
| Tests | Chemical analysis, Tensile test, Intergranular corrosion test, Metallographic examination |
Applications
- Automotive drive shafts, axles, suspension components, steering systems, and structural tubing requiring high strength and corrosion resistance.
- Aerospace structural components, hydraulic lines, landing gear tubing, and precision mechanical parts in aircraft assemblies.
- Industrial machinery rollers, cylinders, bearings, shafts, spindles, and heavy-wall hollow bar for rotating or load-bearing equipment.
- Oil & gas drilling rigs, offshore platforms, downhole tools, wellhead components, and high-pressure mechanical tubing.
- Construction structural supports, frameworks, columns, and architectural elements in corrosive or marine environments.
- Manufacturing machined parts, tooling, dies, bushings, and custom precision mechanical assemblies.
- Power generation and chemical processing equipment including pump shafts, valve bodies, and heat-resistant mechanical components.
- Food & beverage or pharmaceutical processing machinery frames, conveyors, and hygienic mechanical tubing where cleanability matters.
- General engineering and heavy equipment fabrications requiring seamless reliability, machinability, and long-term durability after proper qualification.
