This article references authoritative data from the Metals Materials Encyclopedia to provide a detailed analysis of the performance characteristics and processing applications of H13 hot work tool steel. H13 (4Cr5MoSiV1) is the most widely used hot work tool steel internationally, offering excellent high-temperature strength, thermal fatigue resistance, and hardenability.
1. H13 Basic Information
H13 (corresponding to 4Cr5MoSiV1 in GB/T 1299-2014, JIS SKD61, DIN 1.2344) is a Cr-Mo-V type hot work tool steel widely used in high-temperature service conditions such as hot forging dies, die-casting dies, and extrusion dies. Its excellent comprehensive performance makes it the global benchmark for hot work tool steels.
2. Chemical Composition (wt%)
| Element | H13 (ASTM A681) | 4Cr5MoSiV1 (GB/T 1299) | Function |
|---|---|---|---|
| Carbon (C) | 0.32-0.45 | 0.32-0.45 | Ensures matrix hardness and wear resistance |
| Silicon (Si) | 0.80-1.20 | 0.80-1.20 | Improves high-temperature strength and oxidation resistance |
| Manganese (Mn) | 0.20-0.50 | 0.20-0.50 | Deoxidizer, improves hardenability |
| Chromium (Cr) | 4.75-5.50 | 4.75-5.50 | Forms carbides, improves hardenability and temper resistance |
| Molybdenum (Mo) | 1.10-1.75 | 1.10-1.75 | Improves high-temperature strength and resistance to temper softening |
| Vanadium (V) | 0.80-1.20 | 0.80-1.20 | Refines grain size, improves wear resistance |
| Phosphorus (P) | ≤0.030 | ≤0.030 | Impurity, the lower the better |
| Sulfur (S) | ≤0.030 | ≤0.030 | Impurity, the lower the better |
3. Mechanical Properties
| Property | Value | Conditions |
|---|---|---|
| Hardness (Annealed) | ≤229 HBW | Annealed, ≤229 HBW |
| Hardness (Quenched + Tempered) | 44-52 HRC | 1020°C oil quenching + 550-600°C tempering, depending on tempering temperature |
| Tensile Strength (Rm) | 1200-1550 MPa | Quenched + tempered condition (hardness 44-50 HRC) |
| Yield Strength (Rp0.2) | 1000-1300 MPa | Quenched + tempered condition |
4. Heat Treatment Process
The correct heat treatment process for H13 is critical to final performance:
- Annealing: 845-900°C, furnace cool to 500°C then air cool, hardness ≤229 HBW
- Preheating: 600-650°C + 850-900°C two-stage preheating (large dies must be heated in stages)
- Quenching temperature: 1020-1050°C, oil cooling or high-pressure gas quenching
- Tempering temperature: 530-600°C (usually double tempering, each for 2h or more, to avoid temper embrittlement)
- Hardness after quenching: 52-56 HRC (as-quenched), adjusted to 44-52 HRC by tempering
- Surface treatment: Can be nitrided to improve surface hardness and wear resistance (nitrided layer hardness can reach 900-1100 HV)
5. Typical Applications
- Die-casting dies: Aluminum/zinc alloy die-casting cores and inserts (the largest application area for H13)
- Extrusion dies: Aluminum profile extrusion dies, extrusion container liners
- Hot forging dies: Hot forging punches, hot forging die cavities
- Plastic molds: Injection molds requiring long service life and high polishability
- CNC machined parts: Precision wear-resistant parts under high-temperature conditions
6. CNC Machining Performance
CNC machining of H13 requires strategies based on hardness state:
- Annealed state (≤229 HBW): Good machinability, coated carbide tools can be used
- Pre-hardened state (35-42 HRC): Moderate machining difficulty, ultrafine grain carbide or CBN tools recommended
- Hardened state (44-52 HRC): Hard turning or grinding required, CBN tools recommended
- Cutting speed reference: Roughing 60-100 m/min, finishing 80-150 m/min (annealed state)
- Tool selection: Coated carbide tools (AlTiN coating preferred), CBN tools (hardened state)
7. International Grade Comparison
| Standard System | Grade |
|---|---|
| ASTM (USA) | H13 |
| GB/T (China) | 4Cr5MoSiV1 |
| JIS (Japan) | SKD61 |
| DIN/EN (Germany/Europe) | 1.2344 / X40CrMoV5-1 |
8. Purchasing Guide
Market price reference (2024):
- Hot-rolled plate/bar: 20-35 CNY/kg (annealed state)
- Precision ground stock (machined on all six sides): +3-5 CNY/kg
- Electroslag Remelting (ESR) H13: 30-45 CNY/kg (higher purity and isotropy)
- Purchasing considerations: Verify material certificates, inspect chemical composition, ultrasonic testing (for large die blocks)
Data references: ASTM A681, GB/T 1299, NADCA #207
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