JIS G3131 — Hot-rolled mild steel plates, sheets and strip
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Scope
Technical delivery conditions for hot-rolled mild steel sheet, plate and strip in three forming grades: SPHC (commercial), SPHD (drawing) and SPHE (deep drawing), in thicknesses from 1.2 to 14 mm. Specifies chemical composition, tensile strength, elongation by thickness and the pickled variant (suffix P). No yield strength, impact energy or carbon equivalent is guaranteed — structural grades are in JIS G3101 and G3106.
Grades covered by JIS G3131
| Grade | No. | Type | C % | Yield MPa | Tensile MPa | Nearest equivalents |
|---|---|---|---|---|---|---|
| SPHC | Hot-rolled mild steel sheet and strip for commercial and drawing quality | ≤ 0.15 | not specified | ≥ 270 | DD11, DD12, DD13 |
Revision history and superseded standards
| Year | Change |
|---|---|
| 1996 | Three-grade SPHC/SPHD/SPHE structure established |
| 2005 | Revision aligned with ISO practice |
| 2018 | Current edition; pickled designation and thickness ranges clarified |
Supersedes: JIS G3131:1996; JIS G3131:2005.
Where to buy the standard
The full text is copyrighted by JISC and is not reproduced here. Purchase the current edition from Japanese Standards Association (JSA) or your national standards body. The values on this site are the normative limits as published; the standard's own tables, notes and test methods govern.
Related standards
SPHC is a forming grade, not a structural one
JIS G3131 covers hot-rolled mild steel plates, sheets and strip in three forming grades: SPHC commercial, SPHD drawing and SPHE deep drawing. What the standard guarantees is tensile strength and elongation — and, deliberately, no yield strength at all.
That omission is the point. A forming grade with a yield floor would have to be rejected for being too soft, which is the opposite of what a press shop wants. It also means SPHC cannot be used where a structural calculation needs a guaranteed yield; the Japanese structural grades are in G3101 and G3106.
The P suffix and the EN counterparts
A P after the grade — SPHC-P — marks pickled material, with the mill scale removed in acid and the surface oiled. Black material carries the scale and cannot be pressed into a visible part or welded cleanly without further preparation.
Against European practice the family maps onto EN 10111: SPHC to DD11, SPHD to DD12 or DD13, SPHE to DD13 or DD14. The correspondence is close on chemistry and looser on mechanical guarantee, because the EN grades specify a yield range where JIS specifies none.