304 Stainless Steel Capillary Tube is a precision thin-wall stainless steel tubing product for applications requiring small diameter, dimensional accuracy and smooth surface quality. ASTM A269 is commonly specified for this type of austenitic stainless steel tubing.
SAKY STEEL supplies 304 / UNS S30400 capillary tubing with customized outside diameter, inside diameter, wall thickness, fixed length and surface requirements. Bright annealed and polished surfaces are available according to the confirmed specification.
For precision capillary tubing, buyers should confirm not only the material grade but also OD, ID, wall thickness, cut length, tolerance and surface requirement.
| Item | Specification |
|---|---|
| Grade | 304 / UNS S30400 |
| Standard | ASTM A269 |
| Product Type | Stainless Steel Capillary Tube |
| Outside Diameter | Customized Small Diameter |
| Inside Diameter | Customized according to OD and wall thickness |
| Wall Thickness | Thin Wall Customized |
| Length | Fixed Length / Customized |
| Surface | Bright Annealed / Polished |
| Surface Roughness | Inspection available according to confirmed requirement |
| Certificate | MTC / EN 10204 3.1 Available |
Capillary tube dimensions are normally defined by outside diameter, inside diameter or wall thickness, together with the required finished length.
| Parameter | Meaning |
|---|---|
| OD | Outside Diameter |
| ID | Inside Diameter |
| WT | Wall Thickness |
| L | Finished Length |
| Precision Dimensions Small OD and thin-wall dimensional control | Smooth Surface Bright annealed or polished surface options | Good Formability Suitable for precision fabrication requirements | Custom Cut Length Fixed-length tubing according to order |
304 stainless steel is an austenitic chromium-nickel stainless steel. Final batch composition should be confirmed by the supplied material test certificate.
| Element | Content |
|---|---|
| Carbon (C) | ≤0.08% |
| Chromium (Cr) | 18.0–20.0% |
| Nickel (Ni) | 8.0–10.5% |
| Manganese (Mn) | ≤2.0% |
| Silicon (Si) | ≤1.0% |
| Iron (Fe) | Balance |
Mechanical properties depend on manufacturing process, heat treatment condition, tube dimensions and applicable specification.
| Property | Reference Requirement |
|---|---|
| Tensile Strength | ≥515 MPa |
| Yield Strength | ≥205 MPa |
| Elongation | ≥35% |
| Hardness | According to ASTM A269 requirements |
| Item | Supply Range |
|---|---|
| Outside Diameter | Customized Small Diameter |
| Inside Diameter | Customized |
| Wall Thickness | Thin Wall Customized |
| Length | Fixed Length / Customized |
| Surface | Bright Annealed / Polished |
The following inspection-report images are retained as actual document evidence. Results shown in these documents apply to the relevant tested sample or batch only.
Production and finishing processes depend on the required tube dimensions and specification. Typical processing stages include:
| Inspection Item | Purpose |
|---|---|
| Chemical Analysis | Verify stainless steel grade composition |
| Dimensional Inspection | Check OD, ID, wall thickness and length |
| Surface Inspection | Verify surface finish and appearance |
| Surface Roughness | Verify roughness when specified |
| Eddy Current Testing | Available when specified for tube integrity verification |
| MTC / EN 10204 3.1 | Material traceability documentation |
| Instrumentation Measurement and control systems | Laboratory Equipment Precision fluid and gas components | Analytical Equipment Small-diameter transfer tubing |
| Sensors & Controls Small tubing for precision systems | Medical Components Precision components subject to specification review | Custom Components Cut-to-length precision stainless tubing |
SAKY STEEL uses suitable export packaging to protect capillary tubes against surface damage, contamination and bending during transportation.
Please provide OD, ID or wall thickness, finished length, quantity and any requirements for tolerance, straightness or surface roughness.
Yes. Surface roughness inspection can be performed according to the confirmed requirement.
No. Ra 0.135 μm is the measured result shown for the displayed test sample only. It is not a universal guaranteed value for all 304 stainless steel capillary tubing.
Yes. Fixed-length and customized cut-length tubing can be supplied according to the required dimensions and tolerance.
Send the required OD, ID or wall thickness, finished length, quantity, tolerance and surface requirement. SAKY STEEL can review the specification and provide a quotation.
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