Stainless Steel Metric Tubing — ISO 1127 | 304 / 316L / 321 / 2205
Precision metric OD tubing for instrumentation, sanitary, hydraulic and structural service. Seamless & welded per EN 10216-5 / EN 10217-7, ASTM A269/A213/A312. Finishes: AP, BA, MP, EP. MTR/COA supplied.
- ISO 1127 tolerances
- 316L sanitary tube
- 304/304L instrumentation
- Duplex 2205/2507
Why Metric Stainless Tubing?
Fits global equipment using metric OD ferrules, compression fittings, and sanitary unions.
Excellent corrosion resistance with 316L, 904L, and duplex options for chlorides and harsh media.
Precision OD/ID and straightness for instrumentation and motion systems.
Hygienic surface options (MP/EP) for food, beverage, pharma and semiconductor utilities.
Grade Selection Guide
| Grade | UNS | Strength/Corrosion | Notes | Typical Uses |
|---|---|---|---|---|
| 304 / 304L | S30400 / S30403 | Good / Good | General-purpose; 304L for improved weldability | Instrumentation, structural, dry media |
| 316 / 316L | S31600 / S31603 | Good / Very good (chlorides) | Mo improves pitting resistance; 316L for welds | Sanitary, marine, chemical, hydraulic |
| 321 | S32100 | Good / Good | Ti stabilized for higher temperature service | Exhaust, heat exchangers |
| 310S | S31008 | Medium / Good (high-temp) | Heat resistance up to elevated temps | Furnace, thermal equipment |
| 904L | N08904 | Medium / Excellent | High Ni-Mo-Cu; strong acid/chloride performance | Pharma, chemical, offshore |
| 2205 Duplex | S32205/S31803 | High / Excellent (pitting) | High strength; good stress corrosion resistance | Desalination, oil & gas, marine |
| 2507 Super Duplex | S32750 | Very high / Outstanding | Superior PREN; severe chloride environments | Subsea, chemical, high-pressure lines |
Share fluid, temperature, chlorides, and pressure—our engineers will recommend the optimal grade and finish.
Metric Size Range & Capability
Below ranges guide RFQs. If your size isn’t listed, send your spec—custom drawing and finishing available.
Round Tube (Metric OD)
OD: 4 / 6 / 8 / 10 / 12 / 14 / 16 / 18 / 20 / 22 / 25 / 28 / 30 / 32 / 38 / 42 / 50 / 60.3 / 63.5 / 76.1 / 88.9 / 101.6 / 114.3 / 139.7 / 168.3 mm
Wall: 0.5 / 0.6 / 0.8 / 1.0 / 1.2 / 1.5 / 2.0 / 2.5 / 3.0 / 4.0 / 5.0 mm (grade-dependent)
Length: 6 m standard; cut-to-length; randoms & fixed lengths on request
Precision / Sanitary Options
- Precision ID/OD for compression fittings (instrumentation)
- Sanitary tube with MP/EP ID; controlled Ra and passivation
- Hydraulic tube with tight ovality and cleanliness specs
Example Size Table (Metric OD)
| OD (mm) | Wall (mm) | ID (mm) | Est. Weight (kg/m) | Finish | Notes |
|---|---|---|---|---|---|
| 6 | 1.0 | 4.0 | 0.12 | BA | Instrumentation |
| 12 | 1.5 | 9.0 | 0.40 | AP/BA | Compression fittings |
| 25 | 2.0 | 21.0 | 0.96 | MP/EP | Sanitary line |
| 50 | 2.5 | 45.0 | 2.90 | AP | Process utility |
| 76.1 | 3.0 | 70.1 | 5.40 | AP | Structural/utility |
Weights are estimates for stainless at 7.93 g/cm³; confirm on quotation/MTR for exact grade and tolerances.
Product Packaging
Adopting a professional industrial packaging solution that is moisture-proof and scratch resistant, each batch of steel is tied and fixed with customized wooden frames/steel strips, combined with anti rust coatings and cushioning pads to ensure zero damage during transportation. Clear product model, batch number, and storage identification on the outer packaging, supporting customized enterprise logos and information labels. Environmentally friendly and recyclable packaging materials practice green concepts, reducing transportation and disassembly costs.
Common Applications
Instrumentation & Controls
Precision OD for ferrule fittings; BA/EP surfaces minimize trap sites.
Food & Beverage / Pharma
MP/EP ID with controlled Ra for hygienic flow paths and easy CIP/SIP.
Hydraulic & Pneumatic
Tight ovality and cleanliness; 316L or duplex for strength and corrosion.
Processing & Services
- Cut-to-length (±0.5 mm typical), deburr, ID cleaning & capping
- OD polishing (MP), ID electropolish (EP), passivation
- Hydro/pressure test, PMI, surface roughness test reports
- Export packing: PE bagged, end-capped, VCI wrap, plywood crates
Quality & Compliance
- MTR/COA with heat numbers; hardness and chemistry per grade
- Dimensional checks: OD, wall, ovality, straightness per ISO 1127
- Surface verification: Ra (MP/EP), visual & boroscope on request
- Traceable packing list, photos, and full export documentation
Frequently Asked Questions (FAQs)
What tolerances can I expect?
ISO 1127 covers OD, wall, ovality and straightness. We’ll confirm a tolerance class or custom limits per application (instrumentation, sanitary or structural).
What Ra can you achieve for sanitary/EP tubing?
Typical MP: Ra ≤0.8 μm; EP: Ra ≤0.25 μm ID (tighter on request). We provide surface test records when specified.
Can you supply heat traceability and PMI?
Yes, tubes are heat-numbered with PMI and chemistry reports available. Positive material ID can be performed per lot or per item.
Do you offer bent or fabricated spools?
We provide cutting, bending (radius limits apply), end forming, and welding with pickling/passivation as specified.
Why Global Clients Choose Us?
Henan Gengfei Industrial Co., Ltd. is China’s leading supplier of steel and other metal products. Our company is dedicated to providing its customers with the quick quotes, superior quality products, competitive prices and fastest possible deliveries.
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