H13 vs 1.2344: Same Steel or Not? A Practical Guide for Die Makers

If you have ever received two quotations — one offering "H13" and another "1.2344" — for what looks like the same die casting tool, you are not alone. These two designations are used almost interchangeably in the tool steel trade, yet they come from two different standards systems, and the difference matters more than most buyers expect.

Two standards, one steel family

H13 is the American designation, registered under AISI/SAE and covered by ASTM A681. Designation 1.2344 comes from the German DIN system (material number 1.2344, steel name X40CrMoV5-1), and it is now also referenced in EN ISO 4957. Japanese SKD61 belongs to the same family.

Both are 5% chromium hot work tool steels with molybdenum and vanadium additions, designed for high thermal fatigue resistance. Typical chemistry requirements look like this:

Read together, the two columns tell the real story: H13 is a wider, more tolerant specification; 1.2344 is a tighter, more European one. Both can describe steel that performs identically in service — but they also leave room for material that sits at opposite ends of the permitted range.

What actually differs in practice

In our experience supplying both grades to die casting shops, three things decide whether you get a good die or a headache:

1. Where the material sits inside the range. A heat of H13 with 0.35% C and 1.1% Mo behaves differently from one at 0.44% C and 1.7% Mo. The second offers better hot hardness and temper resistance; the first is easier to machine. For large HPDC dies where thermal cracking dominates, the higher alloy end is usually the better buy.

2. Cleanliness. Phosphorus and sulphur levels, oxide inclusions and banding have more influence on polishability and die life than the choice between the two designations. Premium material — often produced by ESR or vacuum degassing — is specified with tighter limits, and any serious mill certificate states them.

3. Certification. A supplier who can only say "same as H13" is not the same as one who issues an EN 10204 3.1 mill test certificate showing the actual heat analysis, hardness and, on request, ultrasonic test results.

When they are interchangeable — and when they are not

· Interchangeable: general hot forging dies, die casting inserts, extrusion tooling, and most repair or replacement work where you control heat treatment in-house. Chemistry in the overlapping range will give the same response to hardening and tempering.

· Not interchangeable without checking: where a customer drawing or automotive standard names one exact grade, where a European end user requires EN ISO 4957 certification, or where you rely on a specific supplier's heat treatment recipe. In those cases, buy to the standard named on the drawing, not to the nearest equivalent.

What to ask before you place the order

1. Which standard will the mill certificate be issued to — ASTM A681, DIN 17350 / EN ISO 4957, or both?

2. What are the actual values for carbon, molybdenum and vanadium in the heat offered?

3. Is the material ESR / vacuum degassed, and what are the P and S limits?

4. What is the delivery condition and hardness (typically annealed, max. 229 HB)?

5. Which sizes are available from stock, and which require a mill rolling?

How we supply

We stock and supply both H13 and 1.2344 hot work tool steel in rounds from 20 mm to 500 mm, flat bars and cut blocks, all with mill test certificates and the option of third-party inspection before shipment. Whether you need the American designation for a US customer or 1.2344 for a European one, the answer is the same steel — supplied with the paperwork your customer actually asks for. View our H13 hot work tool steel and 1.2344 tool steel product pages for sizes, stock and certificates.

 Need a quotation or a sample certificate? Email sales@better-toolsteel.com or message us on WhatsApp at +86 139 0723 1780. Tell us the grade, size and quantity, and we will come back with price, availability and lead time within one working day.