GOST 380 — Carbon steel of ordinary quality. Grades
Last updated
Scope
Grades and chemical composition of ordinary-quality carbon steel: St0 to St6, each in rimmed (kp), semi-killed (ps) and killed (sp) deoxidation practice. The standard fixes chemistry only. Mechanical properties come from the product standards that call it up — GOST 535 for sections, bars and shapes, GOST 14637 for heavy plate and GOST 16523 for thin sheet — which is why a St3sp certificate always names two standards.
Grades covered by GOST 380
| Grade | No. | Type | C % | Yield MPa | Tensile MPa | Nearest equivalents |
|---|---|---|---|---|---|---|
| St3sp | — | Carbon structural steel of ordinary quality (GOST / CIS) | 0.14 – 0.22 | 245 | 370–480 | s235jr, s235j0, q235 |
Revision history and superseded standards
| Year | Change |
|---|---|
| 1971 | St0–St6 grade ladder with kp / ps / sp deoxidation suffixes established |
| 1988 | Chemistry tightened; category system (1–6) formalised for test scope |
| 1994 | Interstate edition adopted across the CIS |
| 2005 | Current edition; residual limits for Cr, Ni and Cu stated explicitly |
Supersedes: GOST 380-94; GOST 380-88; GOST 380-71.
Where to buy the standard
The full text is copyrighted by Rosstandart / EASC (interstate standard) and is not reproduced here. Purchase the current edition from Rosstandart (protect.gost.ru) 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
A grade standard with no mechanical properties
GOST 380 defines the ordinary-quality carbon steels — St0 through St6 — and their chemical composition. It contains no mechanical properties at all.
Yield, tensile, elongation and impact come from the product standard that calls the grade up: GOST 535 for sections and bar, GOST 14637 for heavy plate, GOST 16523 for thin sheet. A complete certificate therefore names two standards, and one that names GOST 380 alone has specified a chemistry and nothing else. This surprises buyers used to EN and ASTM, where the grade standard carries both.
The suffix and the category are separate decisions
Two annotations follow the grade and they do different jobs. The deoxidation suffix — kp rimmed, ps semi-killed, sp killed — changes only the silicon content, and structural work should be ordered sp: rimmed steel has a segregated core and is not a welding material.
The category digit, as in St3sp5, sets the test scope. Category 1 requires chemistry and tensile only; 3 adds impact at +20 °C; 4 at −20 °C; 5 at −20 °C and after mechanical ageing; 6 at −40 °C. Reading an S235J2 requirement across to plain "St3sp" without a category drops the toughness half of the specification.