Copper Brazing vs Silver Welding - Which Makes Best Carbide Burr

One of the toughest and most wear-resistant materials is the tungsten carbide used to manufacture rotary burrs. The extremely sharp cutting blades can grind and cut through some of the hardest metals without exhibiting any wear.

But the strength of carbide burrs depends on how well they are attached to the stainless steel shank. If there are weaker connections, excessive pressure may cause the head to break off. The two techniques utilized to establish this connection will be covered in this article, along with the possible causes of some of your carbide burrs breaking.

COPPER BRAZING: THE TRADITIONAL METHOD

The majority of producers join their carbide burr heads to their shanks using copper brazing. This procedure entails applying a copper-based filler to the steel shank, sliding it into the carbide head, and heating it to melt the filler, which, when cooled, forms a braze joint. Although this technology is economical, it has certain disadvantages: 

• ELEVATED BRAZING TEMPERATURES: Brazing copper necessitates temperatures of approximately 1100°C (2012°F), which is in close proximity to the cobalt melting point seen in carbide alloy. The carbide burr head may occasionally become weakened by these high temperatures. 
• STRESS AND THE POTENTIAL FOR MICRO-CRACKS: The notable disparity in thermal expansion between tungsten carbide and copper can lead to stress during the cooling process, which raises the possibility of microcracks. 
• SOFTER JOINT: Because copper is a softer metal, it may bend and move more easily in joints, particularly in high-vibration situations.

SILVER SOLDERING: THE MODERN IMPROVEMENT

A more recent technique that manufacturers less frequently employ is silver soldering. A silver flat-bottom solder is used in this procedure to join the burr head and shank. When the solder cools, it forms a bond, having melted at a temperature lower than that of copper brazing. Compared to copper brazing, it offers the following benefits:

Although less common, silver soldering has a number of benefits over copper brazing.

• REDUCED BRAZING TEMPERATURES: Compared to copper, silver solder alloys melt at temperatures between 700 and 800°C (1292–1472°F). By using this technique, the carbide head is less likely to sustain heat damage, and the cobalt binder is preserved.
• STRONGER, MORE DURABLE BOND: Compared to copper brazing, silver soldering frequently produces a stronger, more resilient bond that is far less likely to break under strain. 
• SUPERIOR CORROSION RESISTANCE: Compared to copper braze, silver solder has a higher resistance to corrosion, allowing the burrs to endure longer in more hostile conditions.

BENCHMARK ABRASIVES' APPROACH TO SILVER SOLDERING AND SINTERING

At Benchmark Abrasives, we think that the best techniques and materials should be used to make the most powerful and effective carbide burrs. For this reason, we use a special silver soldering and sintering procedure while producing carbide burrs.

OUR METHOD:

• PRECISION FIT: First, we make sure that the stainless steel shank and carbide burr head fit precisely. By doing this, gaps are reduced, and ideal contact for the soldering process is guaranteed. 
• SILVER SOLDERING: To attach the burr head and shank, we use a premium silver solder alloy that has a low melting point. This reduces the amount of heat exposure and maintains the carbide's cobalt concentration. 
• SINTERING: The joint is heated to a high temperature below the melting point following soldering. This creates a tiny link that strengthens the tungsten carbide-shank bond, resulting in a joint that can endure the most demanding applications. 
• QUALITY CONTROL: To guarantee the integrity of the joint and the burr's overall function, each burr is put through extensive quality control testing. Our goal is to provide customers with tools that are both exceptional and long-lasting.

THE OUTCOME:

Our sintered carbide burrs and silver soldered burrs from Black Hawk Abrasives boast:

• UNMATCHED STRENGTH: By combining silver soldering and sintering, the carbide head and shank are joined in a more consistent and incredibly strong manner, thereby removing the possibility of breaking under pressure.
• MAXIMUM DURABILITY: Our burrs retain their hardness and wear resistance for a longer tool life by minimizing heat damage and maintaining the cobalt concentration.
• BETTER PERFORMANCE: Even in the most demanding applications, smooth, effective cutting and grinding with little vibrations are made possible by the optimum carbide integrity and secure connection.
• CORROSION RESISTANCE: Even under challenging working conditions, our carbide burrs are less likely to deteriorate over time due to silver's inherent resistance to corrosion.

COPPER BRAZING VS SILVER SOLDERING

CONCLUSION

The longevity and performance of tungsten carbide burrs depend on the soldering technique used. While silver soldering, particularly when paired with sintering, offers superior benefits that can result in better performance and durability, copper soldering is still sufficient for many applications. This is especially crucial in harsh industrial settings where tools must sustain their efficacy over time due to heavy use.