How to Improve the Tungsten Carbide Cold Forging Dies’ Service Life
1) When cold forging on M5 or below small screws, we generally use tungsten carbide compounding dies, taking single set structure, the proportion of inner and outer diameter for the carbide die cores is 2~3, the inner diameter of sleeve and carbide core is reasonable at 2~2.5.But the tungsten carbide die core and sleeve height are decided as per the actual situation.
2) The tungsten carbide material grade that we generally take YG20C ,YG20 and YG15,but if take YG15 or YG15C ,you would get much more wear-resitance and longer service life than the YG20C .
3) When do the cold-pressing inlaying process ,the tungsten carbide die cores’ outer diameter and inner hole of the sleeve are designed with taper shape ,the conical degree is 1°～2°,and cone face and its bottom junction bound make round and smooth transition with R 1~1.5mm,meanwhile ,the inner diameter of carbide core working end must take rounding with R0.3~0.6mm,the bottom face of the inner hole of sleeve should make hidden-chip groove ,and make the undersides of the inner hole of the sleeve and carbide core into be convex .At last the sleeve hardness must reach HRC40~44,the cold-inlaying interference coefficient taking 0.8%~1.0% of carbide core is reasonable .
