H13 material exhibits optimal overall performance when its hardness is between 48 and 52 HRC, achieving a balance between high strength, good toughness, and excellent wear resistance. It is suitable for molds operating under high pressure and high temperature conditions.
1. Key Performance Indicators
|
Performance Indicators |
Performance |
Description |
|
Hardness |
48~52 HRC |
Too low and it's prone to collapse; too high and it's brittle. This range is the optimal balance. |
|
Impact Toughness |
15~20 J/cm² |
Significantly improved fracture resistance; >18 J/cm² is excellent. |
|
Abrasion Resistance |
Significantly enhanced. |
Fine, dispersed carbides support the matrix, slowing down the wear rate. |
|
Thermal Fatigue Life |
Extended by more than 30%. |
Uniform microstructure, consistent expansion during thermal cycling, and delayed cracking. |
|
Residual Stress |
≤100 MPa |
Low stress, significantly reducing the risk of cracking during processing and service. |
Practical Application: H13 hot runner nozzles tempered at 580℃ for 2 hours twice exhibit a stable hardness of 49.8 HRC, an impact toughness of 17.3 J/cm², and a lifespan exceeding 500,000 cycles.
2. Metallographic Characteristics
Matrix Structure: Uniform tempered martensite + diffusely distributed fine carbides;
No Abnormal Structure: No untempered martensite, network carbides, or grain boundary oxidation;
Structure Uniformity: No significant differences in structure between thick and thin areas, avoiding a "hard surface, soft interior" appearance.
Recommendation: Sample ≥5% of each batch and observe under a 400× microscope to ensure a clean and uniform microstructure.
3. Process and Quality Assurance
Perform two tempering cycles: After the first tempering, the sample must be air-cooled to room temperature before the second tempering to completely release stress;
Precise Temperature Control: Use a PID temperature control furnace, set at 580℃±5℃, with a furnace temperature difference ≤±5℃;
Sufficient Holding Time: ≥2 hours each time, with an additional 30 minutes for every 25mm of thickness for thicker parts;
Data Archiving: Save furnace temperature curves and test records for traceability.
Security principles: "Data archiving, organizational trustworthiness, and performance compliance"-the combination of these three is the most reliable.
