What is SPA-H steel?
SPA-H is a weathering steel designation associated with JIS G 3125, the Japanese specification for superior atmospheric corrosion resisting rolled steels. Use the agreed standard edition and the ordered product form when checking acceptance requirements.
A purchase order should identify more than a familiar grade name. The size schedule, delivery condition, test records and processing scope determine what the supplier must quote and document. SHANDONG DAZHI welcomes SPA-H enquiries for review; stock, available dimensions and lead time are confirmed in the quotation.
SPA-H specification and order parameters
| Parameter | Details to establish before ordering |
|---|---|
| Standard / designation | JIS G 3125, SPA-H; state the edition required by the project. |
| Product form | Plate, sheet or cut blank; identify the intended processing route. |
| Thickness, width and length | Give dimensions in millimetres and the quantity for each line item. |
| Dimensional acceptance | Specify thickness tolerance, flatness, edge condition and cut-size tolerance. |
| Chemical composition | Check the applicable SPA-H limits against the heat analysis and agreed specification. |
| Mechanical properties | Confirm tensile, yield and elongation requirements for the product and thickness being ordered. |
| Delivery condition and surface | Agree the required condition and any surface preparation separately. |
| Inspection documents | State the certificate type, heat traceability and additional testing required by the purchaser. |
No single stock range or price is implied by this checklist. Send your requirements for a supply review. The material certificate guide explains which records to compare with the purchase order.
Discuss the application before choosing the material
For transport panels, enclosures, outdoor assemblies or architectural components, provide the drawing and service conditions with the enquiry. These are project contexts for assessment, not a blanket statement that SPA-H satisfies every design requirement. See the transport and equipment guide for the information to include.
If the design includes forming or welding, identify bend geometry, joint details and finish expectations. Ask the fabricator to review the actual material specification and proposed process. Our fabrication checklist helps structure that discussion.
For outdoor use, flag coastal exposure, retained moisture, drainage and contact with adjacent finishes so the design team can assess suitability. Read the exposure checklist before assuming an unpainted finish is appropriate.
How to request a comparable SPA-H quotation
- List SPA-H and the governing standard edition on each applicable order line.
- Attach a size schedule with thickness, width, length, quantity and unit convention.
- Separate full sheets from cut parts and include drawings for processed items.
- State inspection, marking, packaging and delivery requirements.
- Provide the destination and requested Incoterm so freight scope is clear.
Compare offers on the same material and delivery basis. For cost planning, use our weathering steel price guide; an indicative calculation does not replace a written quotation.
SPA-H purchasing FAQ
Is SPA-H automatically interchangeable with Corten A or ASTM A588?
No automatic substitution should be assumed. Compare the governing specifications, product form and project requirements, and obtain the responsible engineer's approval for an alternative. See the grade comparison guide.
Can I order cut-to-size SPA-H sheets?
Send the cutting list, tolerances and drawing files. Processing feasibility, dimensions and traceability arrangements will be reviewed for the quotation.
What thicknesses are available?
Availability is order-specific. Provide your required thickness and quantity; the quotation should identify the proposed supply and any exceptions rather than assuming a universal stock range.
How do I verify the material is SPA-H?
Review the material designation, heat identification and inspection records against the agreed purchase specification. Surface colour or a photograph alone cannot prove grade identity.
What information is needed for a price?
Start with grade, standard edition, dimensions, quantities, processing and destination. Include certificate requirements and delivery terms to reduce clarification rounds.