AISI H13 Hot Work Tool Steel: Die Casting & Forging Dies vs AISI P20 Pre-Hardened Mold Steel: Plastic Injection Molding Standard
Side-by-side engineering comparison of AISI H13 Hot Work Tool Steel: Die Casting & Forging Dies (ASTM A681) and AISI P20 Pre-Hardened Mold Steel: Plastic Injection Molding Standard (ASTM A681 (modified)). Compare mechanical properties, chemical composition, density, yield strength, international equivalents, and typical applications to select the right material for your project.
Quick Comparison
| Property | AISI H13 Hot Work Tool St | AISI P20 Pre-Hardened Mol |
|---|---|---|
| Standard | ASTM A681 | ASTM A681 (modified) |
| Category | Tool Steel | Tool Steel |
| Density | 7.80 g/cm³ | 7.85 g/cm³ |
| Yield Strength | 1,380 MPa (200 ksi) at 48-50 HRC | 850 MPa (123 ksi) at 28-32 HRC |
| Tensile Strength | 1,580 MPa (229 ksi) at 48-50 HRC | 1,000 MPa (145 ksi) at 28-32 HRC |
| Key Applications | AISI H13 is the most widely used hot work tool steel with 0.32-0.45% C, 4.75-5.50% Cr, 1.10-1.75% Mo, and 0.80-1.20% V. ... | AISI P20 is a chromium-molybdenum pre-hardened mold steel supplied at 28-32 HRC—ready for machining directly into plasti... |
International Equivalents
| AISI H13 Hot Work To Equivalents | AISI P20 Pre-Hardene Equivalents |
|---|---|
| EN X40CrMoV5-1 | EN 40CrMnNiMo8-6-4 |
| DIN 1.2344 | DIN 1.2738 |
| SKD61 | NAK80 |
| 4Cr5MoSiV1 | 3Cr2Mo |
| JIS SKD61 | P20+Ni |
How to Choose
| Choose AISI H13 Hot Work Tool St when... | H13 is a through-hardening hot work steel for aluminum die casting and forging dies operating at 540°C. |
| Choose AISI P20 Pre-Hardened Mol when... | P20 is pre-hardened (28-32 HRC) mold steel for plastic injection molding—machined directly, no post-machining heat treatment needed.. |
Selection Guide
Choose H13 for hot work tooling that operates above 200°C — die casting dies, forging dies, extrusion tooling, and plastic molds running at elevated temperatures. Choose P20 for plastic injection molds running below 200°C where the pre-hardened condition (28-32 HRC) allows machining directly to final dimensions without post-machining heat treatment.
Key Decision Factors
- Operating temperature — H13 for above 200°C; P20 for below 200°C. This is the primary decision criterion
- Heat treatment requirement — P20 is used pre-hardened (no heat treatment); H13 must be hardened and tempered after machining
- Production volume — H13 provides 10-50× longer die life in hot work applications; P20 is adequate for short-run cold molds
- Cost and lead time — P20 molds are faster and cheaper to produce; H13 requires additional heat treatment and finish grinding
When to Use Each
Use AISI H13 Hot Work To for:
H13's exceptional hot hardness (retains 45 HRC at 540°C), thermal fatigue resistance, and toughness make it the universal standard for aluminum die casting.
H13 withstands repeated thermal cycling between ambient and 1000°C+ billet contact temperatures without cracking or softening.
When mold temperatures exceed 200°C (engineering plastics like PEEK, PPS), H13 provides the necessary hot hardness that P20 cannot maintain.
Use AISI P20 Pre-Hardene for:
P20 is pre-hardened to 28-32 HRC — machine directly to final dimensions with no post-machining heat treatment, reducing lead time by 2-4 weeks.
P20's lower cost and faster machining make it economical for short-run prototype molds where die life beyond 50,000 shots is not required.
P20 is available in large blocks (up to 1000mm thick) and machines easily, making it standard for large automotive and appliance mold bases.
Frequently Asked Questions
What is the main difference between AISI H13 Hot Work Tool Steel: and AISI P20 Pre-Hardened Mold Ste?
AISI H13 Hot Work Tool Steel: Die Casting & Forging Dies (ASTM A681) provides 1,380 MPa (200 ksi) at 48-50 HRC yield strength at 7.80 g/cm³ density, while AISI P20 Pre-Hardened Mold Steel: Plastic Injection Molding Standard (ASTM A681 (modified)) delivers 850 MPa (123 ksi) at 28-32 HRC at 7.85 g/cm³. The choice depends on whether your application prioritizes hot work tooling (die casting, forging, extrusion) or plastic injection molds running below 200°C.
Can AISI H13 Hot Work Tool Steel: be substituted for AISI P20 Pre-Hardened Mold Ste?
In many applications, these materials can be cross-referenced, but direct substitution should always be verified against specific project specifications, especially for hot work tooling (die casting, forging, extrusion), plastic injection molds running below 200°C, and operating environment. Consult your engineer of record.
Can P20 be used for die casting?
No. P20 softens rapidly above 200°C and cannot withstand die casting operating temperatures (600-700°C molten metal contact). Die casting dies always require H13 or equivalent hot-work steel. Using P20 for die casting would result in rapid softening, heat checking, and catastrophic die failure.
Why is P20 pre-hardened?
P20 is supplied at 28-32 HRC specifically so mold makers can machine it directly to final cavity dimensions without subsequent heat treatment. This eliminates the distortion risk associated with hardening and the need for post-hardening EDM or grinding. The trade-off is lower hardness and wear resistance compared to through-hardened steels.
How many shots can I expect from an H13 die casting die?
Properly heat-treated H13 dies typically produce 50,000-200,000 shots before major maintenance, depending on casting geometry, aluminum temperature, and die temperature cycling. With proper surface treatment (nitriding), shot count can exceed 500,000. P20 would fail after only a few hundred shots in the same application.
What surface treatments work on H13?
Nitriding (gas or plasma) is the most common surface treatment for H13, providing a 0.1-0.2mm hard case (65-70 HRC equivalent) that resists soldering and wear in die casting. PVD coatings (TiN, TiAlN, CrN) are used for forging dies. Nitriding typically triples die life in aluminum die casting applications.
Can P20 be hardened after machining?
Yes, but it is not standard practice. P20 can be through-hardened to 44-52 HRC by austenitizing at 840-870°C, quenching, and tempering. However, this introduces distortion risk and requires final grinding — negating P20's primary advantage. If a harder mold is needed, specify H13 or S7 from the start.