Materials E-Guide
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Within the on-road transportation industry, heat exchangers (plate and fin), catalytic converters and EGR coolers have several things in common. They are constructed of relatively thin, stainless steel sheet metal and these sheets are brazed together to construct the component. As such, manufacturers of these components want to braze them at as low a temperature as possible to both minimize distortion and control manufacturing costs. Yet the braze alloys traditionally used — AWS BNi-2 and AWS BNI-5 — are relatively costly because of their high nickel content and braze temperature ranges.
More Efficient Braze Filler Metals for Heat Exchanges, Catalytic Converters and EGR Coolers
Metco Joining & Cladding offers braze alloys that:
- Replace some of the filler metal nickel with iron, thereby reducing the overall cost of the braze alloy and helping to control varying nickel pricing
- Braze at significantly lower temperatures further reducing both processing costs and the chance of part distortion
- Are highly corrosion and oxidation resistant as they have high chromium content
- Are boron-free, eliminating boron diffusion into grain boundaries that can compromise joint integrity
- Produce braze joints that are strong and ductile
Introducing Amdry 105 and Amdry 806A
Amdry 105 and Amdry 106A are braze filler metals that have been specifically designed to meet the needs of plate and fin heat exchanger, catalytic converter and EGR cooler manufacturers.
Corrosion and Oxidation Resistance
The generous chromium content in Amdry 105 and Amdry 806A results in braze joints that are very corrosion and oxidation resistant.
Test Joints of Amdry 105 or
|
Results (microscopic exam) of Braze Joint |
| 150 hour, 10% H2SO4 Aqueous Solution | No corrosion |
| 150 hour, 10% HCL Aqueous Solution | No corrosion |
| 150 hour, 10% NaCl Aqueous Solution | No corrosion |
| 24 hour, 810 °C (1500 °F) Air atmosphere Furnace | No weight reduction versus pre-test weight |
Brazing Range
Amdry 105 and Amdry 806A braze at lower temperatures compared to traditional AWS BNI-2 and AWS BNI-5. This reduces processing time and cost as it takes less time to reach the optimum brazing temperature and less time for furnace cool down. Of course, and perhaps most important, is the lower braze temperature reduces the potential for component distortion.
Braze Filler Metal |
Braze Range |
| BNi-2 | 1010 to 1175 °C (1850 to 2150 °F) |
| BNi-5 | 1150 to 1205 °C (2100 to 2200 °F) |
| Amdry 105 | 1066 to 1121 °C (1950 to 2150 °F) |
| Amdry 806A | 1050 to 1100 °C (1922 to 2012 °F) |
Gap Size
These braze filler metals are designed to fill long, narrow gaps, making them an ideal choice for heat exchangers, catalytic converters and EGR coolers.
| Braze Filler Metal | Flow | Gap Size |
| Amdry 105 | Free-flowing | 12.5 to.5 μm (0.0005 to 0.004 in) |
| Amdry 806A | Medium-flowing | 25 – 100 µm (0.001 – 0.004 in) |
Additional Outstanding Features
Braze joints of Amdry 105 and Amdry 806A exhibit strength and ductility that is very comparable to AWS BNI-2 and AWS BNI-5. They are manufactured using dry gas atomization, which results in very homogeneous composition and highly repeatable results.
