Overview
H11 Tool Steel is a chromium-based hot work tool steel known for its excellent combination of toughness, thermal fatigue resistance, heat resistance, hardenability, and impact strength. Classified under the AISI H-series hot work tool steels, H11 is widely used in tooling applications exposed to repeated heating and cooling cycles.
Compared with H13 tool steel, H11 offers higher toughness and better crack resistance but slightly lower wear resistance and hot hardness. Its exceptional thermal shock resistance makes it ideal for die casting, forging, extrusion, and hot forming operations.
H11 is widely used in:
- Die Casting Dies
- Forging Dies
- Extrusion Tooling
- Hot Punches
- Hot Shear Blades
- Aluminum Casting Molds
- Aerospace Tooling
- Plastic Mold Components
Because of its excellent resistance to thermal cracking and impact loading, H11 is one of the most trusted hot-work tool steels worldwide.
Material Specification
| Property | Value |
|---|---|
| Material Designation | H11 Tool Steel |
| Standard | ASTM A681 |
| UNS Number | T20811 |
| Material Family | Chromium Hot Work Tool Steel |
| Density | 7.80 g/cm³ |
| Magnetic Property | Magnetic |
| Typical Supply Condition | Annealed |
| Standard Forms | Round Bar, Flat Bar, Plate, Block, Forgings |
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron (Fe) | Balance |
| Carbon (C) | 0.33–0.43 |
| Chromium (Cr) | 4.75–5.50 |
| Molybdenum (Mo) | 1.10–1.75 |
| Vanadium (V) | 0.30–0.60 |
| Silicon (Si) | 0.80–1.20 |
| Manganese (Mn) | 0.20–0.50 |
| Phosphorus (P) | ≤0.030 |
| Sulfur (S) | ≤0.030 |
The chromium and molybdenum content provide excellent hot strength and thermal fatigue resistance, while vanadium improves wear resistance and grain refinement.
Mechanical Properties
Annealed Condition
| Property | Value |
|---|---|
| Tensile Strength | 800–1000 MPa |
| Yield Strength | 600–800 MPa |
| Hardness | 180–230 HB |
| Elastic Modulus | 210 GPa |
Hardened & Tempered Condition
| Property | Value |
|---|---|
| Hardness | 44–52 HRC |
| Toughness | Outstanding |
| Thermal Fatigue Resistance | Excellent |
| Impact Resistance | Excellent |
Hot Work Condition
| Property | Value |
|---|---|
| Hot Strength | Excellent |
| Thermal Shock Resistance | Outstanding |
| Heat Checking Resistance | Excellent |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.80 g/cm³ |
| Melting Point | 1420–1460°C |
| Thermal Conductivity | 28 W/m·K |
| Electrical Resistivity | 0.55 μΩ·m |
| Thermal Expansion Coefficient | 11.8 × 10⁻⁶/K |
| Specific Heat Capacity | 460 J/kg·K |
Corrosion Resistance
| Environment | Performance |
|---|---|
| Indoor Environment | Moderate |
| Dry Atmosphere | Good |
| Humid Environment | Moderate |
| Outdoor Environment | Moderate |
| Marine Environment | Poor |
| Chemical Environment | Poor |
H11 is not a stainless steel and should be protected from corrosion during storage and operation.
Recommended surface treatments:
- Nitriding
- Gas Nitriding
- PVD Coating
- QPQ Treatment
- Black Oxide
- Hard Chrome Plating
Weldability
| Welding Process | Rating |
|---|---|
| TIG Welding | Good |
| MIG Welding | Good |
| Arc Welding | Good |
| Laser Repair Welding | Excellent |
| Tool Steel Repair Welding | Excellent |
H11 is widely recognized for its excellent weld repair capability compared with many other tool steels.
Recommended:
- Preheat: 300–400°C
- Controlled Cooling
- Post-Weld Tempering
Machinability
| Process | Rating |
|---|---|
| CNC Turning | Good |
| CNC Milling | Good |
| Drilling | Good |
| Grinding | Excellent |
| EDM Machining | Excellent |
| Wire EDM | Excellent |
Machinability Comparison
| Material | Machinability |
|---|---|
| O1 Tool Steel | Excellent |
| A2 Tool Steel | Good |
| H11 Tool Steel | Good |
| H13 Tool Steel | Good |
| D2 Tool Steel | Fair |
Heat Treatment
Annealing
| Parameter | Value |
|---|---|
| Temperature | 840–870°C |
| Cooling Method | Furnace Cool |
Preheating
| Parameter | Value |
|---|---|
| Temperature | 815–870°C |
Hardening
| Parameter | Value |
|---|---|
| Temperature | 995–1035°C |
| Cooling Medium | Air or Oil |
Tempering
| Parameter | Value |
|---|---|
| Temperature | 540–650°C |
| Cycles | Double or Triple Temper Recommended |
Hardness After Heat Treatment
| Condition | Hardness |
|---|---|
| Annealed | 180–230 HB |
| Hardened | 50–54 HRC |
| Hardened & Tempered | 44–52 HRC |
Nitriding
| Property | Value |
|---|---|
| Surface Hardness | 900–1200 HV |
| Wear Resistance | Excellent |
| Die Life Improvement | Significant |
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM / AISI (USA) | H11 |
| UNS | T20811 |
| GB/T (China) | 4Cr5MoSiV |
| EN (Europe) | X38CrMoV5-1 |
| DIN (Germany) | 1.2343 |
| JIS (Japan) | SKD6 |
| ISO | X38CrMoV5-1 |
Available Forms
| Product Type | Availability |
|---|---|
| Round Bar | Yes |
| Flat Bar | Yes |
| Tool Steel Plate | Yes |
| Mold Blocks | Yes |
| Forgings | Yes |
| Pre-Hardened Blocks | Yes |
| Precision Ground Stock | Yes |
Typical Applications
Die Casting Industry
- Aluminum Die Casting Dies
- Magnesium Die Casting Dies
- Die Inserts
- Core Components
Forging Industry
- Forging Dies
- Hammer Dies
- Press Dies
- Upsetting Tools
Extrusion Industry
- Extrusion Dies
- Mandrels
- Hot Forming Tools
Aerospace Industry
- Hot Forming Tooling
- Structural Component Dies
- Precision Forging Dies
Plastic Mold Industry
- High-Temperature Mold Components
- Mold Inserts
- Core Blocks
General Engineering
- Hot Shear Blades
- Hot Punches
- Thermal Shock Components
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| CNC Machining | Excellent |
| Precision Grinding | Outstanding |
| EDM Machining | Excellent |
| Wire EDM | Excellent |
| Heat Treatment | Outstanding |
| Nitriding | Outstanding |
| Weld Repair | Outstanding |
Advantages
Outstanding Toughness
Superior toughness compared with many hot-work tool steels.
Excellent Thermal Fatigue Resistance
Resists heat checking and thermal cracking.
High Hot Strength
Maintains performance at elevated temperatures.
Excellent Shock Resistance
Suitable for impact-loaded hot-work tooling.
Good Weldability
Ideal for repair and maintenance welding.
Long Tool Life
Performs well under repeated thermal cycling.
Limitations
Lower Wear Resistance Than H13
Not ideal where maximum abrasion resistance is required.
Moderate Corrosion Resistance
Requires protective coatings.
More Expensive Than Carbon Tool Steels
Due to alloying content and processing requirements.
Requires Proper Heat Treatment
Performance depends heavily on heat treatment quality.
Comparison with Other Tool Steels
| Property | H11 | H13 | S7 | D2 | A2 |
|---|---|---|---|---|---|
| Toughness | Outstanding | Excellent | Exceptional | Moderate | Excellent |
| Hot Strength | Excellent | Outstanding | Moderate | Poor | Poor |
| Thermal Fatigue Resistance | Excellent | Outstanding | Moderate | Poor | Poor |
| Wear Resistance | Good | Better | Moderate | Outstanding | Excellent |
| Weldability | Excellent | Good | Good | Poor | Fair |
Comparison with Hot Work Tool Steels
| Material | Hardness | Hot Strength | Thermal Fatigue Resistance |
|---|---|---|---|
| H11 | 44–52 HRC | Excellent | Excellent |
| H13 | 44–54 HRC | Outstanding | Outstanding |
| H21 | 50–56 HRC | Outstanding | Good |
| H10 | 42–50 HRC | Excellent | Excellent |
| S7 | 54–58 HRC | Moderate | Moderate |
Available Surface Finishes
Raw Finishes
- Annealed Finish
- Forged Finish
- Ground Finish
- Precision Machined Finish
Functional Finishes
- Hardened Finish
- Nitrided Finish
- Precision Ground Finish
- EDM Finish
Protective Finishes
- Black Oxide
- QPQ Treatment
- Hard Chrome Plating
- PVD Coating
- Gas Nitriding
Frequently Asked Questions (FAQ)
What is H11 tool steel?
H11 is a chromium-based hot-work tool steel designed for high-temperature applications requiring toughness, thermal fatigue resistance, and impact strength.
What is H11 steel used for?
Typical applications include:
- Die Casting Dies
- Forging Dies
- Extrusion Dies
- Hot Punches
- Hot Shear Blades
What is the equivalent material to H11?
Common equivalents include:
- DIN 1.2343
- SKD6
- X38CrMoV5-1
- 4Cr5MoSiV
What is the difference between H11 and H13?
| Property | H11 | H13 |
|---|---|---|
| Toughness | Higher | Lower |
| Wear Resistance | Lower | Higher |
| Thermal Fatigue Resistance | Excellent | Outstanding |
| Hot Hardness | Lower | Higher |
What hardness can H11 achieve?
Typically:
- Hardened: 50–54 HRC
- Hardened & Tempered: 44–52 HRC
Is H11 suitable for die casting?
Yes. H11 is widely used for aluminum and magnesium die casting tooling.
Can H11 be nitrided?
Yes. Nitriding significantly improves surface hardness and die life.
Why is H11 preferred for hot-work tooling?
Because it combines:
- High Toughness
- Excellent Thermal Fatigue Resistance
- Good Hot Strength
- Excellent Weldability
- Long Service Life
Is H11 better than H13?
H11 is generally preferred when toughness and crack resistance are more important, while H13 is preferred when wear resistance and hot hardness are critical.
Does GCNOV provide custom manufacturing services for H11 steel?
Yes. GCNOV provides:
- CNC Machining
- Tool & Die Manufacturing
- EDM Processing
- Precision Grinding
- Heat Treatment
- Nitriding
- Weld Repair Services
- Prototype Development
- Low-Volume Production
- Mass Production