JIS G3131 is a Japanese Industrial Standard for hot-rolled mild steel plates, sheets, and strips. For buyers, the main grade choices commonly encountered are SPHC for general use, SPHD for drawing, and SPHE for deep drawing. The right choice depends on the forming severity, finished-part requirements, and the dimensions and surface condition your process needs—not on the grade name alone. In this guide, we explain how to compare grades, specify the material, and prepare a clearer request for quotation.
This guide is for procurement teams, steel service centers, manufacturers, and engineers evaluating hot-rolled low-carbon steel for industrial components. It is particularly useful when a drawing or customer specification calls for JIS G3131 and the buyer needs to distinguish between the available grades. It can also help buyers prepare an RFQ that gives suppliers enough detail to assess the request. It is not a substitute for the governing standard, engineering approval, or application-specific testing.
JIS G3131 covers hot-rolled mild steel products in forms such as plate, sheet, and strip. The standard’s grade designation is one part of the specification, rather than a complete description of every commercial detail. Buyers should also identify product form, thickness, width, length or coil requirements, tolerances, surface condition, and any required inspection or documentation. Always state the edition or revision required by your contract or end customer.
| Grade | General positioning | Buyer consideration |
|---|---|---|
| SPHC | General-purpose hot-rolled mild steel | Consider for routine forming and fabrication where the specified standard and application requirements are met. |
| SPHD | Drawing-quality hot-rolled steel | Consider when the part involves drawing; confirm suitability for the actual shape and forming operation. |
| SPHE | Deep-drawing-quality hot-rolled steel | Consider for more demanding drawing requirements, subject to confirmation against the part design and processing conditions. |
These descriptions are a practical starting point, not a guarantee that a given coil will perform in every forming operation. Actual results can depend on the ordered specification, material condition, tooling, lubrication, blank design, and process control. If a component has strict forming limits or a history of cracking or wrinkling, share that information during material selection. Avoid substituting one grade for another without approval from the responsible engineer or customer.
JIS G3131 grades are used where buyers need hot-rolled mild steel for fabrication or forming. Depending on grade and product condition, applications may include general formed parts, brackets, covers, structural components, and drawn components. These are broad examples, not a guarantee of suitability for a particular part. Verify the required strength, ductility, thickness, surface, and downstream processing requirements against the drawing and applicable standard.
For relatively straightforward fabrication, SPHC may be a starting point if the specification and required properties align. Where the component requires drawing, SPHD may be more appropriate to evaluate; for deeper drawing, SPHE may be worth discussing with the mill or supplier. The labels indicate different intended quality levels, but they do not replace review of the part geometry or a forming trial when one is necessary. For coated, welded, painted, or machined products, also check whether the delivered surface and material condition suit the next process.
A precise RFQ helps suppliers assess feasibility and reduces ambiguity between the drawing, order, and delivered material. Start with the complete grade designation and standard revision required by your project. Then identify product form, dimensions, tolerances, surface condition, quantity, delivery location, and any required documents. If the material will undergo drawing, bending, welding, or another critical operation, describe that process rather than relying on a grade name alone.
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The following figures are examples of how to state dimensions, not JIS limits or a claim about Solucky Steel’s stock range: sheet thickness 2.0 mm, width 1,250 mm, and coil inside diameter 508 mm. Replace them with the values required by your design and handling equipment. State whether dimensions are targets or allowable ranges, and specify the applicable tolerances. Ask the supplier to confirm feasibility and any minimum order conditions before placing the order.
There is no single price or lead time that applies to every JIS G3131 order. These depend on factors such as grade, dimensions, quantity, processing, packaging, delivery destination, and current availability. A special thickness or surface requirement may affect sourcing options, while a larger order may involve different production or logistics planning. Request a written quotation that identifies the offered grade, specification, quantity basis, delivery terms, quotation validity, and any applicable minimum order quantity.
For schedule-sensitive projects, ask the supplier to distinguish material availability from processing and transit time. Confirm whether the quoted timing is an estimate or a committed schedule, and clarify what events could change it. Buyers should also check whether partial shipments are acceptable and how packaging and coil or bundle identification will support receiving operations. These details can matter as much as the nominal unit price when coordinating production.
Choose a supplier based on its ability to understand and confirm the complete specification, not only its ability to quote a grade name. Ask how the offered material will be identified and what documents are available for the order. Confirm how nonconforming dimensions, surface concerns, or document discrepancies are handled. For critical applications, agree on acceptance criteria and any approval or testing steps before production or shipment.
At Solucky Steel, we can discuss JIS G3131 sourcing requirements with buyers and review the requested grade, product form, dimensions, quantity, and delivery destination for a quotation. To help us assess your request, send the applicable standard and revision, a drawing or specification where available, the required surface condition, and your target delivery schedule. We can then clarify the information needed to evaluate availability, processing options, documentation, and commercial terms. Final grade suitability should be confirmed by the buyer’s engineering or quality team for the intended application.
For a general starting point, evaluate SPHC for general-purpose hot-rolled use, SPHD for drawing, and SPHE for deep drawing. The correct choice is the grade and product condition that meet the governing specification and perform acceptably in your actual process. Before ordering, confirm the standard revision, dimensions, tolerances, surface requirements, documentation, and delivery terms in writing. Send Solucky Steel your RFQ or drawing details to discuss the specification and request a quotation.
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