Comparison: LM21 Aluminum vs. China's Equivalent Aluminum Alloy (ZL107)
LM21 aluminum (British standard), a cast Al-Si-Cu alloy, is relatively close in performance and composition to China's cast aluminum alloy grade ZL107. Here is a detailed comparative analysis:
1. Composition Comparison
Element | LM21 (BS Standard) | ZL107 (GB/T 1173-2013) |
---|---|---|
Silicon (Si) | Approximately 6% | 6.5%~7.5% |
Copper (Cu) | Approximately 4% | 3.5%~4.5% |
Aluminum (Al) | Remainder (85.7%~91%) | Remainder |
Other Elements | Trace amounts of Mn, Pb, etc. | Impurities (Fe, Zn, etc.) ≤ specified limits |
2. Performance Comparison
Property | LM21 | ZL107 |
---|---|---|
Tensile Strength | About 190~220MPa in conventional casting | ≥270MPa (sand casting, T6 treatment) |
Yield Strength | 8%~13% improvement with vibration casting | ≥245MPa (sand casting, T6 treatment) |
Elongation | ~3%~5% with optimized vibration casting | ≥2% (sand casting, T6 treatment) |
Hardness (HB) | 16% higher microhardness with vibration casting | ≥100HB (sand casting, T6 treatment) |
Casting Performance | Good, suitable for complex-shaped parts | Excellent fluidity and high air tightness |
3. Similarities in Process and Application
4. Replacement Recommendations
For domestic procurement of materials similar to LM21, ZL107 is the first choice. Its composition and mechanical properties closely match LM21, with a mature domestic supply chain. Performance can be further optimized via heat treatment (e.g., T6) to meet most industrial needs.
If better weldability is required (LM21 has poor weldability due to high copper content), China’s ZL101A (Al-Si-Mg alloy) can be considered, though attention should be paid to differences in mechanical properties.
Summary
LM21 and China’s ZL107 aluminum alloys are highly similar in composition, performance, and application scenarios. ZL107 can be used as a domestic equivalent to LM21, with specific selection requiring further verification based on process requirements (e.g., casting method, heat treatment) and application scenarios.
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