H13 steel (US grade, corresponding to European grade 1.2344) is a widely used hot working die steel. Due to its excellent high temperature performance, wear resistance and thermal fatigue resistance, it is widely used in high temperature and high pressure industrial scenarios. The following is a detailed analysis of its industrial applications and performance:
1. Industrial Application of H13 steel
1. Die-casting mold
- Applicable materials: Mainly used for die-casting of non-ferrous metals such as aluminum alloys, magnesium alloys, and zinc alloys.
- Advantages: It can maintain high hardness and thermal fatigue resistance under repeated impact of high-temperature molten metal (600~800°C), extending the life of the mold.
- Typical parts: automobile engine cylinder block, gearbox housing, 3C product structural parts, etc.
2. Hot forging mold
- Scenario: High-temperature forging (such as steel or titanium alloy parts such as automobile connecting rods, crankshafts, gears, etc.).
- Performance: When subjected to impact loads at high temperatures of 800~1000°C, H13 has excellent resistance to softening and thermal cracking.
3. Extrusion mold
- Application: Extrusion molding molds for aluminum profiles and copper tubes.
- Features: The mold needs to withstand high pressure (>1000 MPa) and high temperature (400~500°C). The high-temperature strength and toughness of H13 can reduce deformation and cracking.
4. Plastic molds
- High finish requirements: used for transparent plastics (such as optical lenses, light guide plates) or high-precision injection molds.
- Performance support: H13 can achieve a mirror effect (Ra < 0.1μm) after polishing, and has high hardness (HRC 48-52) to reduce wear.
5. Other high-temperature molds
- Glass molding molds: withstand high temperatures of glass liquid (>1000°C), and require surface nitriding treatment to enhance oxidation resistance.
- Aerospace: Titanium alloy hot forming molds, H13’s creep resistance meets the needs of long-term high-temperature use.
2. Performance of H13 Steel
1. High temperature strength
It can still maintain a high hardness (>HRC 40) at 500~600°C, thanks to the carbides (such as VC, Mo2C) formed by Cr, Mo, and V to strengthen the matrix.
2. Thermal fatigue resistance
Under hot and cold cycles (such as the melting-cooling process of die-casting molds), H13 has a significantly lower crack growth rate than ordinary mold steel due to its low thermal expansion coefficient and high thermal conductivity.
3. Wear resistance
High hardness (HRC 48-52 after quenching + tempering) and carbide distribution reduce the wear amount by 30%~50% in high-pressure friction environments (such as extrusion molds).
4. Toughness
Compared with H11 steel, H13 optimizes toughness by adjusting the V content (0.8%~1.2%), and the impact energy resistance can reach 15~25 J (room temperature), and it can still maintain a certain plasticity at high temperatures.
5. Heat treatment performance
Good hardenability, can be hardened by air cooling (critical diameter is about 100mm), high tempering stability (secondary hardening peak is 500~550°C).
6. Limitations
Prone to oxidation and softening in >600°C environment for a long time, surface treatment (such as nitriding, PVD coating) is required to improve service life.
3. Typical Process Parameters of H13 Steel
Heat treatment process:
- Quenching: 1020~1050°C oil cooling or air cooling.
- Tempering: 550~600°C double tempering, hardness HRC 48-52.
Surface treatment:
- Gas nitriding: surface hardness can reach HV 1100-1200, depth 0.1~0.3mm.
- TiAlN coating: improve high temperature oxidation resistance (temperature resistance to 900°C).
4. Comparison with Other Hot Working Steels
| Steel type | High temperature strength | Toughness | Thermal fatigue resistance | Typical application scenarios |
| H13 | ★★★★☆ | ★★★★☆ | ★★★★☆ | Die casting, hot forging, extrusion |
| H11 | ★★★☆☆ | ★★★★★ | ★★★☆☆ | Forging dies with high toughness requirements |
| DIEVAR | ★★★★★ | ★★★☆☆ | ★★★★★ | Ultra-long life die casting dies |
Summary
H13 steel has become a “universal steel” in the field of hot working dies due to its balanced high temperature strength, thermal fatigue resistance and processing performance. Its application in extreme working conditions can be further expanded by optimizing heat treatment and surface modification (such as coating). In scenarios such as aluminum alloy die-casting and complex hot forging dies, H13 is still one of the most cost-effective choices.
