Making
a perfect carbide tool starts with a suitable
shank material, which must afford the best
possible support to the carbide tip and
good brazing characteristics. In most cases
it is a mild steel with 700-800 N/mm2
tensile strenght. We recommend grade C 60
W, WNr. 1.1740
For higher operational stresses shanks are
made ot steels 900-1000 N/mm2,
e.g. C85W, WNr 1.1830 There is a general
tendency tor high-duty tools, such as drills,
contersinks and reamers which have to resist
torsional stresses ,to be made of tool steel
grades that can be heat treated from brazing
temperature. Rising percentages of Cr adversely
affect brazability because the chromium
oxide formed resists dissolution by the
fluxes. The grade 40 NiCrMo6,WNr. 1.6565
has done well in high-duty applications.
Apart from suitable shank materials, the
shank crooss section must be adequate to
accomodate the cutting forces. Shank sections
should be chosen with regard to turning
tools standardized under DIN 4971-4981 and
ISO 1-9 which offer adequate stability for
normal machining conditions. Both shank
materials and carbide grades differ as to
their brazability.Rising percentages of
Co improve properties,whereas rising amounst
of complex carbides affect them adversely
because of their poor wettability.
Brazing
Carbide Tips
