Improving Comprehensive Yield Rate of H13 Die Steel Forging: A Technical Analysis

In the field of hot work die steel manufacturing, FUSHUN METAL has conducted extensive research on improving the comprehensive yield rate of H13 die steel forgings. This analysis explores the key factors affecting yield rates and presents effective solutions for optimization.

Understanding H13 Hot Work Die Steel

H13 die steel, characterized by its high alloy content and excellent mechanical properties, is primarily used in manufacturing hot forging dies, hot extrusion dies, die-casting molds, and hot heading dies. Given its application in high-temperature and high-pressure conditions, the material must possess superior strength, hardness, thermal stability, high-temperature strength, thermal fatigue resistance, toughness, and wear resistance.

Current Challenges in Production

The forging process of H13 die steel faces several challenges that affect the yield rate:

• Surface cracking during forming
• Incomplete internal forging
• Internal cracks leading to ultrasonic testing failures
• Lower yield rates compared to ordinary carbon steel (3-5% difference)
• Extended delivery cycles

Key Production Process Steps

At FUSHUN METAL, the production process includes:

1. Cast steel ingot preparation
2. Heating
3. Forging using radial forging machine or quick forging machine
4. Spheroidizing annealing
5. Grinding or peeling
6. Ultrasonic testing
7. End cutting
8. Processing inspection
9. Quality verification and storage

Critical Factors Affecting Yield Rate

1. Steelmaking Process

The primary concerns include low steel purity, internal shrinkage cavities, porosity, and surface defects such as scarfing, inclusions, and steel overflow during casting.

2. Quick Forging Process

Issues arise from improper forging techniques leading to uneven surface deformation, internal cracking due to low final forging temperatures, and excessive processing allowances.

3. Radial Forging Process

Small deformation during forging can result in incomplete internal forging, leading to internal porosity and void defects.

4. Annealing Process

Delayed furnace entry after forging, deviation from prescribed annealing curves, and inadequate heating temperatures or holding times can cause localized stress cracking.

Improvement Measures Implemented

Steelmaking Process Optimization

Focus on controlling superheat and casting procedures, with particular attention to shrinkage compensation time at the hot top to prevent forging welding defects.

Forging Process Enhancement

• Optimized reduction amount control (100-150mm during roughing)
• Implementation of multi-pass forging with controlled final forging temperature
• Modified forging sequence with alternating groove forging method
• Enhanced radial forging parameters with lower frequency forging programs

Annealing Process Improvements

Implementation of hot annealing procedures with immediate post-forging stress relief, optimized furnace loading patterns, and controlled cooling processes.

Grinding, Peeling, and Cutting Optimization

• Two-step grinding process implementation
• Dual-pass peeling process adoption
• Enhanced quality control sequence

Results and Conclusions

Through these comprehensive improvements, the H13 die steel forging process has achieved significant enhancements in quality and efficiency. The implemented measures have resulted in:

• 3.5% increase in comprehensive yield rate
• Improved surface quality and internal structure
• Enhanced ultrasonic testing pass rates
• Reduced material wastage in cold processing
• More consistent product quality

This technical advancement represents a significant step forward in H13 die steel production efficiency and quality control, positioning FUSHUN METAL as a leader in high-performance die steel manufacturing.