Views: 0 Author: Site Editor Publish Time: 2025-11-05 Origin: Site
Forgings are superior to squeeze castings in most mechanical properties (strength, toughness, fatigue strength). However, squeeze castings have significant advantages in manufacturing complex structures, thin-walled parts, and cost control.
The following is illustrated through a detailed comparison table and analysis.
Characteristic | Squeeze Casting | Forging |
Mechanical Properties | ||
Strength&Toughness | Good. Denser structure than conventional castings, but inferior to forgings. | Excellent.Fine grain structure and complete grain flow provide the highest combination of strength and toughness. |
Fatigue Strength | Fairly good. May still contain micro-porosity, which can initiate fatigue cracks. | Superior.The dense structure and continuous grain flow effectively prevent crack propagation. |
Ductility&Impact Toughness | Moderate. As-cast structure has limited ductility. | Very High.The forging process refines the grain structure, resulting in excellent ductility. |
Microstructure | ||
Density/Soundness | Good. High pressure reduces shrinkage and porosity, but not 100% dense. | Optimal.Plastic deformation consolidates internal defects, achieving near 100% density. |
Grain Structure | As-cast structure with relatively coarse grains. | Fine, uniform, recrystallized grain structure. |
Grain Flow Line | No continuous flow lines; isotropic properties. | Continuous grain flow linesthat follow the part's contour, creating anisotropic properties. |
Process Characteristics | ||
Design Complexity | Very High.Can produce parts with complex geometries, internal cavities, and thin walls. | Low.Typically limited to simple, solid, or symmetrical shapes. Complex internal features are difficult. |
Material Utilization | High. Near-net-shape process with minimal machining allowance. | Lower. Requires larger machining allowances and produces flash (material waste). |
Production Cost&Efficiency | High efficiency. Suitable for high-volume production, lower cost per part. | Higher cost. Requires large, powerful equipment and extensive secondary machining. Higher cost per part. |
Dimensional Accuracy&Surface Finish | High dimensional accuracy and good surface finish. | Lower dimensional accuracy, surface scale (oxide layer), and draft angles are required. |
Material Selection | Primarily limited to non-ferrous alloys (Al, Mg, Zn). | Very wide, from non-ferrous metals to high-strength steels, titanium, and superalloys. |
Detailed Explanation
1. The Root Cause of Performance Difference: The State of the Metal
Squeeze Casting: The metal is liquid (or semi-solid) and solidifies in the mold(liquid-solid process). Although high pressure improves solidification, it is inherently a castingprocess and cannot fully eliminate the characteristics of a cast structure.
Forging: The metal is solid and shaped through plastic deformation at high temperatures(solid-solid process). This process, like kneading dough, breaks down the original coarse grain structure and welds internal voids, resulting in a denser, finer-grained material.
Therefore, forgings have an innate advantage in internal quality, which directly translates to higher reliability, strength, and fatigue performance.
2. Fatigue Strength: The Most Critical Difference
The continuous grain flow in a forging allows stress to be distributed smoothly, greatly enhancing fatigue resistance. A small crack finds it very difficult to propagate through the forged structure.
Even with minimal porosity, the grain boundaries and potential micro-defects in a squeeze castingcan serve as initiation points for fatigue cracks. Its fatigue strength is typically only 70% - 80%of a forging's.
How to choose? -- Comparison of application scenarios
Which process to choose depends on the trade-off between the "performance requirements" and "economy/complexity".
1.Typical applications of squeeze castings (with good enough performance and complex shapes)
• Automobiles: engine block, transmission housing, oil pan, steering knuckle, subframe.
• Electronics: 5G base station housings, heat sinks.
• Tools: Electric tool housings (such as electric drill housings).
• Daily-use: High-performance bicycle components.
Features: These parts usually have complex structures and require good sealing, certain strength and excellent casting performance, but the requirements for ultimate strength and fatigue life are not the top.
2. Typical applications of forgings (Performance is the primary indicator)
• Automobiles: engine crankshaft, connecting rod, transmission gear, wheel hub, suspension ball joint.
• Aerospace: Aircraft landing gear, engine turbine discs, blades, key connecting parts.
• Industry: Crankshafts, connecting rods, high-pressure valves, and tools (wrenches, hammers) for heavy machinery.
• Military industry: Gun barrels, firearm components.
Features: These are "security components", which have extremely high requirements for safety, reliability and durability, and usually bear huge dynamic loads. The shape can be relatively simple, but the performance cannot be compromised.
Conclusion
Under the premise of meeting the design requirements, if the performance of the squeeze casting is competent enough, then choosing it will be more economical and the design will be more flexible. If the parts involve personal safety or work under extreme conditions, forgings must be chosen. In recent years, with the advancement of squeeze casting technology, its performance has been continuously improved, forming a strong competitive edge.
