V. Typical Application Cases
| Forging Type | Material | Process Highlights | Technical Breakthrough | Source |
|---|---|---|---|---|
| Nuclear Power Support Ring | Austenitic Stainless Steel | Metal Constructive Technology: Small slabs vacuum packaged → High-temperature forging bonding → Ring rolling | Diameter 15.6m, weld-free. Eliminated segregation and shrinkage defects. | CAS IMR |
| Large Diameter Radial Forged Tube Billet | S32205 Duplex SS | 8.4t square billet → Upset to φ900-1000mm → 3-stage radial forging to φ500-600mm → Anneal + Water Quench | Offshore platform use. First successful domestic batch delivery. | TISCO |
| Cryogenic High-Strength Non-Magnetic Bar | Austenitic SS | Radial forging: Small deformation, high frequency breakdown → Fast forging (upset/draw) → Radial forging: Large deformation, low frequency | Solved surface cracking and microstructure uniformity issues. | - |
| Mast Forgings | 1Cr18Ni9Ti | Flat-V anvils, controlled heats/reduction; Composition optimization (Mo, Nb addition) | Replaced imports, significantly improved yield strength. | - |
| High-Strength SS Forgings | - | Secondary composition design (2-12% Ferrite); Forging ratio control; Solution + Water Quench | 300°C tensile strength ≥421MPa, achieved lightweighting. | - |
VI. Advanced Technologies & Development Trends
1. Metal Constructive Technology (Disruptive Innovation)
Pioneered by the team of Academician Li Yiyi, Institute of Metal Research, CAS. ”Break down into parts, build up into whole.”
- Principle: Multiple homogenized continuous casting slabs are surface-cleaned, vacuum packaged, and subjected to large deformation at high temperature. This achieves solid-state metallurgical bonding, resulting in an interface with microstructure and properties identical to the base metal.
- Advantages: Completely bypasses the segregation, shrinkage, and coarse grain defects inherent in large ingots. Lower cost, stable quality.
- Applied Materials: 316H, S03, 925A, SA508-3, etc. Extended to nuclear, hydro power, and shipbuilding industries.
2. Intelligent Forging
- Simulation: FEM-based forging process simulation to predict metal flow, temperature fields, strain distribution, and microstructure evolution.
- In-line Monitoring: Closed-loop furnace temperature control; real-time force-displacement feedback during forging.
- Digital Workshops: Full-process data traceability from billet to post-forge treatment.
3. Green Manufacturing
- Energy Saving: Waste heat recovery; induction heating replacing gas furnaces.
- Near-Net Shape: Warm forging and precision forging reduce machining allowances, improving material utilization.
- Recycling: Scale recovery, cooling water circulation.
VII. Common Defects and Countermeasures
| Defect Type | Causes | Countermeasures |
|---|---|---|
| Cracking | Uneven heating; Final forging temp too low; Excessive deformation; Low-melting phases in material. | Control heating rate; Strict temperature control; Multiple heats, small reductions. |
| Coarse Grains | Final forging temp too high; Insufficient deformation (<critical deformation); Excessive heating/soaking time. | Ensure sufficient deformation; Control final forging temp; Optimize solution treatment. |
| σ-Phase Precipitation | Duplex SS held too long in 650-950°C range. | Rapid water quench post-forge; Minimize high-temperature dwell time. |
| Surface Cr-Depletion | High-temperature oxidation consumes surface chromium. | Protective atmosphere heating; Coating protection; Remove oxidized layer post-forge. |
| Non-Uniform Microstructure | Insufficient forging ratio; Poor heat/reduction distribution; Improper anvil selection. | Increase forging ratio; Optimize anvil design (e.g., V-anvil); Control deformation uniformity. |
| Residual Shrinkage | Poor ingot quality; Insufficient forging ratio; Incomplete bonding. | Use high-quality billet; Replace ingot with Constructive Technology. |
Post time: Feb-12-2026
