8407 mold steel is a premium chromium-molybdenum-vanadium (Cr-Mo-V) hot work tool steel manufactured using Electroslag Remelting (ESR) technology. Compared with conventional H13 and standard SKD61, 8407 offers improved steel cleanliness, higher toughness, better thermal fatigue resistance, and more consistent mechanical properties, making it one of the preferred materials for demanding hot work tooling.
Designed for high-temperature applications involving repeated heating, cooling, and mechanical loading, 8407 performs exceptionally well in aluminum die casting, hot forging, hot extrusion, and high-pressure casting. Its balanced combination of wear resistance, hot strength, dimensional stability, and toughness helps manufacturers extend mold life, reduce maintenance, and improve production efficiency.
After proper vacuum heat treatment, 8407 typically achieves a working hardness of 48–52 HRC, providing an ideal balance between durability and toughness for long production runs.
What Is 8407 Mold Steel?
8407 is an ESR-refined premium hot work tool steel developed for applications where conventional H13-grade materials may no longer provide sufficient performance.
The ESR refining process removes non-metallic inclusions and improves microstructural uniformity, resulting in cleaner steel with greater reliability under thermal and mechanical stress. This enhanced cleanliness significantly improves resistance to crack initiation, heat checking, and premature die failure.
Because of these advantages, 8407 is widely used in industries such as:
- Automotive manufacturing
- Aluminum die casting
- Magnesium die casting
- Hot forging
- Hot extrusion
- Plastic injection molding
- Aerospace tooling
- Industrial machinery
For manufacturers seeking maximum tool life and stable production, 8407 is often selected as an upgrade over conventional H13 and SKD61.
Key Properties of 8407 Mold Steel
Excellent Toughness
High toughness is essential for hot work tooling exposed to repeated mechanical impact. The refined microstructure of 8407 significantly improves resistance to cracking, edge chipping, and brittle fracture, making it suitable for demanding production environments.
Outstanding Thermal Fatigue Resistance
Repeated heating and cooling cycles eventually cause heat checking in hot work dies. 8407 provides excellent resistance to thermal fatigue, helping maintain cavity integrity during extended production and reducing maintenance frequency.
Stable High-Temperature Strength
Unlike ordinary hot work steels that gradually soften during continuous operation, 8407 maintains stable hardness and mechanical strength at elevated temperatures, improving dimensional accuracy throughout long production cycles.
Low Heat Treatment Distortion
The homogeneous structure produced through ESR refining minimizes distortion during vacuum hardening and tempering. This reduces post-heat-treatment machining and helps maintain dimensional precision for large tooling components.
Excellent Wear Resistance
The optimized alloy design provides reliable wear resistance while maintaining excellent toughness. This combination allows mold cavities, inserts, and core pins to maintain dimensional accuracy during long production runs.
Superior Surface Treatment Compatibility
8407 responds well to advanced surface engineering processes, including gas nitriding, plasma nitriding, PVD coatings, and duplex treatments, allowing further improvements in wear resistance and mold service life.
Chemical Composition
| Element | Typical Content | Function |
|---|---|---|
| Carbon (C) | 0.38–0.40% | Provides hardness and wear resistance while maintaining toughness |
| Chromium (Cr) | 5.0–5.3% | Improves hardenability, oxidation resistance, and high-temperature strength |
| Molybdenum (Mo) | 1.2–1.5% | Enhances temper resistance and thermal fatigue performance |
| Vanadium (V) | 0.8–1.1% | Refines grain structure and improves wear resistance |
| Silicon (Si) | 0.8–1.1% | Increases thermal stability and oxidation resistance |
| Manganese (Mn) | 0.3–0.5% | Improves hardenability and machining performance |
The carefully balanced Cr-Mo-V alloy system enables 8407 to deliver excellent hot toughness without sacrificing wear resistance.
Typical Applications
Aluminum Die Casting Molds
8407 is widely used in high-volume aluminum die casting because of its resistance to thermal fatigue and heat checking.
Typical products include:
- Automotive structural components
- Motor housings
- Battery housings
- Gearbox housings
- Electronic enclosures
Magnesium Die Casting
The excellent combination of toughness and thermal stability makes 8407 suitable for magnesium alloy die casting where molds experience frequent thermal cycling.
Hot Forging Dies
8407 is commonly used for:
- Closed forging dies
- Forging punches
- Upsetting dies
- Hot extrusion tooling
- Heavy-duty forging inserts
Hot Stamping Tools
Automotive hot forming dies require excellent dimensional stability and resistance to thermal cracking. 8407 provides consistent performance throughout long production cycles.
High-Temperature Mold Components
8407 is also widely used for:
- Core pins
- Die inserts
- Sliding components
- Hot runner parts
- Pressure pads
Heat Treatment
Proper heat treatment is essential for maximizing the performance of 8407.
Hardening
- Austenitizing temperature: 1020–1040°C
- Vacuum hardening
- High-pressure gas quenching
Tempering
- Triple tempering recommended
- Tempering temperature: 560–580°C
- Final hardness: 48–52 HRC
Triple tempering minimizes residual stress while improving toughness and thermal fatigue resistance.
Machining Recommendations
8407 is typically machined in the annealed condition before hardening.
Recommended practices include:
- Complete rough machining before heat treatment.
- Leave sufficient finishing allowance.
- Remove the EDM recast layer before final polishing.
- Apply stress relief after heavy machining when necessary.
- Avoid sharp internal corners that concentrate stress during operation.
Following these recommendations helps maximize tool life and machining accuracy.
Surface Treatment
To further improve wear resistance and extend die life, 8407 is compatible with several surface engineering technologies:
- Gas nitriding
- Plasma nitriding
- PVD coating
- Duplex treatment
These treatments increase surface hardness while maintaining the excellent toughness of the steel core.
8407 vs H13 vs SKD61
| Property | H13 | SKD61 | 8407 |
|---|---|---|---|
| Steel Cleanliness | Good | Very Good | Excellent |
| Toughness | Good | Very Good | Excellent |
| Thermal Fatigue Resistance | Good | Very Good | Excellent |
| Heat Treatment Stability | Good | Very Good | Excellent |
| Wear Resistance | Good | Good | Excellent |
| Heat Treatment Distortion | Low | Low | Very Low |
| Cost | $$ | $$$ | $$$$ |
| Best Application | General Hot Work | Premium Hot Work | Long-Life Heavy-Duty Hot Work |
H13 remains a cost-effective solution for general hot work applications. SKD61 offers improved consistency and toughness under the JIS standard. When maximum mold life, thermal fatigue resistance, and production reliability are required, 8407 is often the preferred choice.
How to Choose 8407 Mold Steel
8407 is recommended for manufacturers requiring reliable performance under severe operating conditions.
Choose 8407 when your tooling requires:
- Long production cycles
- Excellent thermal fatigue resistance
- High toughness
- Stable heat treatment performance
- Low maintenance
- Superior dimensional stability
- High-volume aluminum die casting
- Heavy-duty hot forging
For standard hot work tooling with moderate production requirements, H13 or SKD61 may provide a more economical solution.
Frequently Asked Questions
What is 8407 mold steel used for?
8407 is widely used for aluminum die casting, magnesium die casting, hot forging, hot extrusion, hot stamping, and other demanding hot work tooling applications.
Is 8407 better than H13?
8407 generally provides better toughness, cleaner microstructure, improved thermal fatigue resistance, and longer service life than conventional H13, particularly in high-volume production.
Is 8407 the same as SKD61?
No. Although both belong to the Cr-Mo-V hot work steel family, 8407 is a premium ESR-refined grade designed to deliver improved cleanliness, toughness, and performance in demanding applications.
What hardness does 8407 reach?
After proper vacuum heat treatment, 8407 typically achieves 48–52 HRC.
Can 8407 be nitrided?
Yes. Nitriding is commonly used to improve surface hardness, reduce wear, and increase mold service life without significantly affecting the steel’s core toughness.
Is 8407 suitable for aluminum die casting?
Yes. 8407 is one of the preferred materials for high-volume aluminum die casting molds because of its excellent thermal fatigue resistance, dimensional stability, and toughness.
Why Choose KUTU 8407 Mold Steel?
KUTU supplies premium-quality 8407 ESR hot work tool steel for demanding industrial applications worldwide.
Our services include:
- Precision cutting
- Rough machining
- Vacuum heat treatment
- Nitriding support
- Material certification
- Technical consultation
- Fast global delivery
Whether you manufacture die casting molds, forging dies, extrusion tooling, or precision hot work components, KUTU provides reliable 8407 mold steel with consistent quality and professional support to help increase tooling life, improve productivity, and reduce overall manufacturing costs.
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