Measures to eliminate faults in brazing operation

Fault description

Main cause Measure
Instruction Illustration
Brazing
deformation

Blade (hard alloy)


Shank (steel)

Status of stress deformation at room temperature after heating, brazing


Thickness of blade is smaller    than that of shank
Big difference between thermal
   expansion coefficient of blade    and shank

Thicken blade as much as    possible
Fill washer
Cooling slowly (longer heat    preservation time)
Select the shank with thermal    expansion
   coefficient closer to that of    blade

Thickness ratio of blade and shank


Specific ratio of blade thickness and shank width
Brazing crack


Big difference between thermal
   expansion coefficient of blade    and shank


Thickness of blade is smaller    than that of shank


Use low temperature silver welding

Fill washer
Cooling slowly
   (longer heat preservation time)
Increase arc radius R of cutter
   point or chamfer
Cut a slot or groove in the shank



Expand blade's square-to-round


Blade's square-to-round
Brazing
breaking

Brazing surface is polluted
There is foreign body
Brazing is aging
Brazing volume is not enough
The tightness between base and    blade's connecting surface is    not good.
Brazing surface is too rough

Carefully clean brazing surface
Use the brazing material that corresponds
to the size of brazing urface.
Avoid quick heating, ooling slowly (longer heat preservation time)
Add appropriate quantity of flux when drilling through the vent.
Braze immediately after being rinsed
Blade doesn't bend
Make good the roughness of brazing
   surface



Remove milling mark,
use appropriate blade
The check method of brazing status
 
Safety attentions in using [SB Flux No. 6]
 
 
 
 
SB Solid composition of [SB Flux No. 6]: H3BO3KHF2KOHKBF4
Because there is acid KHF2 in the composition, it may produce hazardous HF gas
when being heated. While using, please be careful and follow the following points
While using, please wear protective glass, gloves etc (preventing it from contacting
skin and mucous membrane part like eyes, nose, mouth etc)
While operating, please use absorption exhaust device that can absorb HF gas.
(Don't inhale harmful gas. Besides, don't discharge HF gas to the air)
When it is not needed, please treat it as industrial waste.
 
 
Magnifying glass checking
After being grinded by CBNC or SDC diamond grinding wheel,
use magnifying glass (X 20 times) to observe whether brazing
layer breaks or whether blade cracks
Knocking checking
For instance, lathe tool, place the lathe tool reversely on
the cutting mat, use sinker to knock the shank to observe
whether the blade falls off
Also can use fluorescent penetrant inspection method and
nesslerization method to check