Material number K03006: A106 Grade B
K03006 is the Unified Numbering System designation for A106 Grade B, seamless carbon steel pipe for high-temperature service specified in ASTM A106.
Reading K03006 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 03006 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. K03006 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.
K03006 identity card
| Item | Value |
|---|---|
| UNS number (ASTM E527) | K03006 |
| Symbolic grade name | A106 Grade B |
| Steel group | K — miscellaneous steels and ferrous alloys |
| Sequential number in group | 03006 |
| Specified in | ASTM A106 |
| Steel family | Pipe & tube steel |
| Yield, first condition in the table | 205 MPa (Grade A) |
| Tensile, same condition | ≥ 330 MPa |
| Cross-references held | 10 grades in 6 systems |
ASTM A106 Grade B / ASME SA-106 Gr B (UNS K03006): the standard seamless carbon steel pipe for high-temperature and pressure service — 240 MPa (35 ksi) yield, 415 MPa (60 ksi) tensile. Grades A/B/C, composition, A106 vs A53 vs API 5L, P235GH/P265GH/STPG370 equivalents.
Full data sheet for A106 Grade B → · Equivalent grades → · ASTM A106 →
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 |
Same UNS letter, so the same alloy family. The digits generally carry an older AISI or SAE number.