Material number T20813: 1.2344
T20813 is the Unified Numbering System designation for 1.2344, hot-work tool steel, 5 % Cr secondary-hardening specified in EN ISO 4957.
Reading T20813 digit by digit
A UNS designation (ASTM E527 / SAE J1086) is a letter followed by five digits. The letter T marks the alloy family — here tool steels — and the five digits 20813 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. T20813 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.
T20813 identity card
| Item | Value |
|---|---|
| UNS number (ASTM E527) | T20813 |
| Symbolic grade name | 1.2344 |
| Steel group | T — tool steels |
| Sequential number in group | 20813 |
| Specified in | EN ISO 4957 |
| Steel family | Tool steel |
| Also carries Werkstoff No. | 1.2344 |
| Tensile, same condition | ≈ 760–850 (typ.) MPa |
| Cross-references held | 8 grades in 5 systems |
1.2344 (X40CrMoV5-1) is the 5 % Cr hot-work tool steel known as H13: working hardness 44–52 HRC, tempered above its service temperature. Composition, heat treatment, and H13/SKD61/4Cr5MoSiV1 equivalents.
Full data sheet for 1.2344 → · Equivalent grades → · EN ISO 4957 →
UNS T — the neighbouring numbers
Same UNS letter, so the same alloy family. The digits generally carry an older AISI or SAE number.