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Stainless steel grades
Send your SS 304H pipe or tube specification, dimensions and inspection requirements to Simplex Metal for a project quote.
Request a quoteTechnical reference
| Field | Order reference |
|---|---|
| Standard | A312 TP304H pipe or A213 TP304H seamless heat-transfer tubing when specified |
| Product or route | High-temperature austenitic grade, UNS S30409 |
| Critical dimensions and fit | State the H grade, design basis and nominal or minimum wall |
| Supply enquiry | Confirm sizes, lengths, route, documentation and lead time for your order |
Selected ASME B36.19 dimensions. Schedule columns give nominal wall thickness. Theoretical inside diameter and mass use nominal dimensions, with a reference density of 8,000 kg/m³. Actual mass varies by grade and tolerances.
| NPS | OD (mm) | 10S wall (mm) | 40S wall (mm) | 80S wall (mm) | 40S ID (mm) | 40S kg/m |
|---|---|---|---|---|---|---|
| 1 | 33.40 | 2.77 | 3.38 | 4.55 | 26.64 | 2.55 |
| 2 | 60.33 | 2.77 | 3.91 | 5.54 | 52.51 | 5.54 |
| 3 | 88.90 | 3.05 | 5.49 | 7.62 | 77.92 | 11.51 |
| 4 | 114.30 | 3.05 | 6.02 | 8.56 | 102.26 | 16.38 |
| 6 | 168.28 | 3.40 | 7.11 | 10.97 | 154.06 | 28.80 |
Reference ASME B36.19 dimensional standard · Tonkin stainless pipe dimensional chart
For tubing, order by actual outside diameter and wall. Drawing example: 25.4 × 2.77 mm minimum-wall tube drawing example.
Use the approved design code and service conditions. The applicable rating depends on material, temperature, minimum effective wall, joint details and the limits of the connected assembly. A schedule or a hydrostatic test result alone cannot establish an operating pressure.
Reference ASME process piping code B31.3
Selected chemistry by mass for the A312 pipe designations below. The ordered edition, full element limits and any applicable notes govern acceptance. A dash means the value is omitted here.
| Grade | UNS | C (%) | Cr (%) | Mo (%) | Grade feature |
|---|---|---|---|---|---|
| TP304H | S30409 | 0.04–0.10 | 18–20 | — | Controlled carbon range |
Reference ASTM A312/A312M scope · Centravis tubular product catalogue · Alleima high-temperature tubular grades
Selected minimum room-temperature tensile and yield strengths for A312 pipe. Elongation acceptance depends on the specimen orientation and applicable thickness basis. For tube orders, apply the nominated tube specification.
| Grade | Tensile minimum (MPa) | Yield minimum (MPa) |
|---|---|---|
| TP304H | 515 | 205 |
Reference ASTM A312/A312M scope · CTS A312 technical reference · Tioga A312 pipe grade reference
Check heat treatment and any grain-size record required by the order.
| When | What to check |
|---|---|
| Before ordering | Document the required test method, edition and any witness points |
| At delivery | Match the material report and heat or lot identification to the shipment |
304L is a different material selection for welded duty.
For the enquiry, state the H grade, design basis and nominal or minimum wall.
A312 TP304H pipe or A213 TP304H seamless heat-transfer tubing when specified · 25.4 × 2.77 mm minimum-wall tube drawing example. Add quantity, lengths, delivery city and the required reports.
Ordering guidance
If the project specifies 304H, quote it as a distinct grade rather than shortening it to 304. Send the required standard and edition, size and manufacturing route. The project engineer’s specification determines whether a proposed alternative is acceptable.
For service at elevated temperature, request the applicable material documentation and inspection scope before pricing. An SS grade alone does not establish an allowable temperature or pressure for the assembled system.
Check pricing and availability →
Buyer’s guide
304H is the elevated-temperature 304-family grade identified by UNS S30409. The H callout may carry additional material requirements under the applicable product standard and edition. If the part is being replaced during a shutdown, use the approved line class or equipment material list to establish the grade. An old label showing only “304” may not contain enough information to issue an order.
A process header ordered by NPS and schedule differs from a superheater tube ordered by actual OD and wall. The applicable pipe or tube standard determines which material and examination requirements must be documented. Send the drawing, specified minimum or nominal wall basis and the required delivery condition with the request.
Request an itemised statement of grade, product specification, manufacturing route and documentary requirements. If the job specifies grain-size evidence, material testing or witness points, place those on the enquiry so they can be priced. Use the design authority’s approved conditions for any assessment of allowable temperature or pressure.
For a furnace tube replacement, attach the tube schedule showing grade, OD, wall basis, finished length and end details. Put inspection and certificate requirements on the same line to make exclusions easy to spot.
A proposed change needs approval against the design and material specification. Diameter and wall alone cannot establish suitability for high-temperature duty.
Technical references Alleima high-temperature tube grades · ASTM steel standards directory
Prepare your enquiry
| Item | What to send |
|---|---|
| Product details | 304H · product standard and edition · pipe schedule or tube wall · test requirements |
| Delivery | Quantity with units, delivery city and required date if known |
| Acceptance | Required certificates and inspection scope; attach the drawing revision where applicable |
UNS S30409 — A 304-family grade for orders with specified elevated-temperature material requirements.
Match markings and traceability to the material documents and check that the specified 304H grade appears against the line item.
Technical reference: Grade designation reference
Project enquiries
Send your dimensions, quantities and delivery city. Include any inspection or material certificate requirements so they can be quoted against the same line items.
Request a quote → Call +91 99204 92715