3  Things You Have to Know about PDC Brazing

PDC cutters are brazed to the steel or matrix body of the PDC drill bit. According to the heating method, the brazing method can be divided into flame brazing, vacuum brazing, vacuum diffusion bonding, high-frequency induction brazing, laser beam welding, etc. The Flame brazing is easy to operate and widely used. Today we’d like to share a little about PDC flame brazing.

What’s flame brazing?

Flame brazing is a welding method that uses a flame generated by gas combustion for heating. The main process of flame brazing includes pre-weld treatment, heating, heat preservation, cooling, post-weld treatment, etc.

What’s the process of PDC flame brazing？

1. Pre-weld treatment

(1) sandblast and clean the PDC cutter and the PDC drill bit body. The PDC cutter and drill bit must not be stained with oil.

(2) prepare solder and flux. We generally use 40%~45% silver solder for PDC brazing. The flux is used to prevent oxidation during brazing.

2. Heating and heat preservation

(1) Preheat the PDC drill bit body into the intermediate frequency furnace to around 530℃.

(2) After preheating, use the flame gun to heat the bit body and PDC cutter. We will need two flame guns, one for the heating of the drill bit body and one for the heating of the PDC cutter. 

(3) Dissolve the solder in the PDC recess and heat it until the solder melts. Put the PDC into the concave hole, continue to heat the drill bit body until the solder is melted and flowed and overflowed, and slowly jog and rotate the PDC during the soldering process. Apply flux to the place where the PDC cutter needs to be brazed to prevent oxidation.

3. Cooling and post-weld treatment

(1). After the PDC cutters are brazed, put the PDC drill bit into the heat preservation place in time, and slowly cool the temperature of the drill bit. 

(2) After cooling the drill bit to 50-60°, we can take out the drill bit, sandblast and polish it. Carefully check whether the PDC welding place is welded firmly and whether the PDC is welded damaged.

What’s the brazing temperature?

The failure temperature of the polycrystalline diamond layer is around 700°C, so the temperature of the diamond layer must be controlled below 700°C during the welding process, usually 630~650℃.

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