{"id":3661,"date":"2026-10-29T12:29:31","date_gmt":"2026-10-29T04:29:31","guid":{"rendered":"http:\/\/www.tuti-industrial.com\/blog\/?p=3661"},"modified":"2026-10-29T12:29:31","modified_gmt":"2026-10-29T04:29:31","slug":"which-din-mold-steel-is-best-for-high-temperature-plastic-molding-46d2-bba547","status":"publish","type":"post","link":"http:\/\/www.tuti-industrial.com\/blog\/2026\/10\/29\/which-din-mold-steel-is-best-for-high-temperature-plastic-molding-46d2-bba547\/","title":{"rendered":"Which DIN mold steel is best for high-temperature plastic molding?"},"content":{"rendered":"

As a DIN plastic mold steel supplier with over a decade of hands-on experience serving mold makers and plastic processors across Europe and beyond, I get asked this question at least twice a week: \u201cWhich DIN mold steel is best for high-temperature plastic molding?\u201d It\u2019s not a trivial question\u2014high-temperature molding, which typically involves materials like PEEK, PI, PPS, and LCP, exposes mold tools to sustained temperatures of 280\u00b0C to 450\u00b0C, paired with high injection pressures, abrasive fillers, and corrosive byproducts that can eat away at standard mold steels in weeks, not years. DIN Plastic Mold Steel<\/a><\/p>\n

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I\u2019ve seen countless mold shops cut corners here, grabbing a cheap DIN steel off the shelf only to watch their molds fail mid-production, leading to downtime that costs more than the steel itself. That\u2019s why I\u2019m breaking down the core DIN mold steel grades that actually perform in high-temperature molding, what makes them stand out, and how to pick the right one for your specific application.<\/p>\n

First, let\u2019s clarify what \u201chigh-temperature plastic molding\u201d means in practical terms for DIN steel. DIN 1.2344, 1.2080, and 1.2767 are the most common mold steels, but they\u2019re not all built for 350\u00b0C+ runs. High-temperature molding demands steels that can resist thermal softening (so they don\u2019t deform under heat and pressure), have good hot hardness (ability to maintain strength at elevated temperatures), wear resistance (to stand up to glass or carbon fillers that are standard in engineering plastics), and sometimes corrosion resistance (from chlorine or fluorine in additives or plastic monomers).<\/p>\n

1. DIN 1.2344: The Workhorse for Most High-Temperature Molding<\/h3>\n

If there\u2019s a go-to for general high-temperature plastic molding, it\u2019s DIN 1.2344. Officially designated as X40CrMoV5-1, this is a hot work tool steel that\u2019s been the industry standard for injection molds since the 1970s, and for good reason.<\/p>\n

Let\u2019s get technical for a second: 1.2344 has a chromium content of ~5%, molybdenum ~1.2%, vanadium ~0.5%, and carbon ~0.4%. This combination gives it exceptional hot hardness\u2014at 400\u00b0C, it retains 80% of its room-temperature hardness, which is critical for molds running 300\u00b0C to 380\u00b0C. Unlike cold work steels that soften dramatically at high heat, 1.2344\u2019s microstructure is engineered to hold its shape.<\/p>\n

I\u2019ve supplied 1.2344 to customers molding PPS with 40% glass fiber, a material that\u2019s notoriously abrasive. One client in automotive was running 100,000 cycles on a 1.2344 mold for a PPS sensor housing, and it was still in spec when they upgraded their production line. Compare that to a cheaper cold work steel like 1.2080, which wore out after 22,000 cycles on the same job.<\/p>\n

That said, 1.2344 isn\u2019t perfect. It does have a limit: sustained temperatures above 400\u00b0C can start to degrade its properties, and it\u2019s not the most corrosion-resistant grade. If you\u2019re molding fluoropolymers (like PTFE) or plastics with chlorine-based additives, the breakdown of those materials releases corrosive gases that can pit 1.2344\u2019s surface over time. For that, you need a different grade.<\/p>\n

2. DIN 1.2767: For Corrosive High-Temperature Applications<\/h3>\n

Enter DIN 1.2767, or X38CrMoV12-1, the go-to for corrosive high-temperature molding. I see this most often with customers molding PTFE, PVDF, or engineering plastics with flame retardant additives that release chlorine. The 12% chromium content here is the key difference from 1.2344\u2019s 5%: it forms a dense chromium oxide layer on the steel\u2019s surface that resists corrosion from those acidic gases.<\/p>\n

Hot hardness is still strong here, too\u20141.2767 maintains ~75% of its room hardness at 450\u00b0C, making it suitable for runs up to that temperature. Last year, a medical parts manufacturer came to me with a problem: their mold for PEEK surgical components (molded at 380\u00b0C) was pitting after just 15,000 cycles, and they couldn\u2019t figure out why. It turned out their PEEK had a chlorine-based biocompatible additive, and 1.2344 couldn\u2019t handle the corrosion. Swapping to 1.2767 extended the mold life to 75,000 cycles, a 400% improvement.<\/p>\n

The tradeoff? 1.2767 is more expensive than 1.2344, and it\u2019s slightly less wear-resistant. For non-abrasive, corrosive high-temp runs, it\u2019s worth the premium, but if your material has glass or carbon fillers, you\u2019ll want to pair 1.2767 with a surface treatment (like nitriding or TiCN coating) to boost wear resistance.<\/p>\n

3. DIN 1.2080: Wait, No\u2014Don\u2019t Use This for High-Temp Molding<\/h3>\n

I can\u2019t talk about DIN steel for high-temp molding without addressing the biggest mistake I see shops make: reaching for DIN 1.2080 (X210Cr12) as a \u201ccheaper alternative.\u201d It\u2019s a cold work tool steel, priced lower than 1.2344, but it\u2019s designed for cold shearing and piercing, not hot injection molding.<\/p>\n

At temperatures above 250\u00b0C, 1.2080 softens dramatically. I had a customer test this a couple years back: they used 1.2080 for a mold running 320\u00b0C for LCP, and after just 5,000 cycles, the mold\u2019s cavity was deformed from pressure, leading to bad parts and a $12,000 downtime bill. 1.2080 is great for low-temp molding (under 250\u00b0C) or non-plastic applications, but it has no place in high-temperature runs. Save it for another job.<\/p>\n

4. DIN 1.2367: The Premium Grade for Extreme High-Temp Runs<\/h3>\n

For the most demanding high-temperature applications\u2014think molding PI (polyimide) at 420\u00b0C, or PEEK with 50% carbon fillers\u2014there\u2019s DIN 1.2367 (X38CrMoV5-3), often called the \u201csuper hot work tool steel.\u201d It\u2019s a more advanced variant of 1.2344, with higher vanadium and molybdenum content, giving it far better hot hardness and wear resistance.<\/p>\n

1.2367 retains almost 90% of its room hardness at 400\u00b0C, and can handle sustained temperatures up to 450\u00b0C without softening. I supplied 1.2367 to a aerospace parts manufacturer molding PI turbine components, a job that required precise cavity dimensions to within 0.002mm over 100,000 cycles. A 1.2344 mold would have started losing tolerance after 30,000 cycles, but the 1.2367 mold held tight the entire run.<\/p>\n

The downside? 1.2367 is significantly more expensive than 1.2344, and it\u2019s harder to machine, so lead times can be longer. It\u2019s overkill for most general high-temp jobs, but if you\u2019re running ultra-high-performance plastics or needing 100,000+ cycles, it\u2019s worth the investment.<\/p>\n

How to Choose the Right DIN Steel for Your Job<\/h3>\n

It\u2019s not just about picking the \u201cbest\u201d steel\u2014it\u2019s matching the grade to your specific material and production requirements. Here\u2019s a quick checklist I share with customers:<\/p>\n