Material number K03005: A53 Grade B
K03005 is the Unified Numbering System designation for A53 Grade B, pipe steel for general and structural service, welded or seamless specified in ASTM A53.
Reading K03005 digit by digit
A UNS designation (ASTM E527 / SAE J1086) is a letter followed by five digits. The letter K marks the alloy family — here miscellaneous steels and ferrous alloys — and the five digits 03005 place the composition inside it, usually by carrying an older AISI or SAE number forward.
What a UNS number does not carry is the product form or the property level. K03005 therefore appears in several ASTM specifications — plate, bar, pipe, forging — each with its own mechanical requirements, and the number alone is not a complete purchase specification.
K03005 identity card
| Item | Value |
|---|---|
| UNS number (ASTM E527) | K03005 |
| Symbolic grade name | A53 Grade B |
| Steel group | K — miscellaneous steels and ferrous alloys |
| Sequential number in group | 03005 |
| Specified in | ASTM A53 |
| Steel family | Pipe & tube steel |
| Yield, first condition in the table | 240 MPa (Grade B — specified minimum) |
| Tensile, same condition | 415 MPa |
| Cross-references held | 7 grades in 5 systems |
ASTM A53 Grade B is the general-service pipe steel: 240 MPa yield, 415 MPa tensile, supplied seamless (Type S), ERW (Type E) or butt welded (Type F). Composition, grades, types and the A106 difference.
Full data sheet for A53 Grade B → · Equivalent grades → · ASTM A53 →
UNS K — the neighbouring numbers
| UNS number | Grade | Type |
|---|---|---|
| K02303 | A572 Grade 50 | High-strength low-alloy (HSLA) columbium-vanadium structural steel |
| K02600 | A36 | Carbon structural steel |
| K02700 | A516 Grade 70 | Carbon steel plate for pressure vessels, moderate and lower temperature |
| K03006 | A106 Grade B | Seamless carbon steel pipe for high-temperature service |
| K03006 | A333 Grade 6 | Carbon steel pipe for low-temperature service, impact tested at −45 °C |
Same UNS letter, so the same alloy family. The digits generally carry an older AISI or SAE number.