during applications sintered carbide pellets have been employed for non ppta hardfacing applications on drill bits in the past but in larger sizes sintered carbide pellets 49 in this application must be small enough to not clog up orifice 45 preferably the largest size of sintered carbide pellets 49 has a maximum diameter less than half of diameter d of orifice 45 diameter d may vary and is 0 045 inch in one example the desired size range for sintered carbide pellets 49 is approximately 37 to 420 microns 0 001 u2033 25 4 microns in diameter and more preferably 75 to 177 microns in the preferred size range a mesh screen size is u2212 60 200 mesh that designation means that the particles being retained will fall through a 60 mesh screen but not pass through a 200 mesh screen as mentioned above hardfacing materials 43 also include spherical cast pellets 51 which are also shown in fig3 spherical cast pellets 51 are conventional and of a conventional size for application with torch 33 spherical cast pellets 51 are generally more spherical than sintered carbide pellets 49 and also small enough to avoid clogging annular passage 41 of torch 33 in the preferred embodiment spherical cast pellets 51 are from 45 to 160 microns in diameter but this range can vary the relative proportion of spherical cast pellets 51 to sintered pellets 49 may differ upon application in one embodiment the ratio was 25 spherical cast pellets 49 and 75 sintered carbide pellets 51 by weight but that ratio could be reversed hardfacing material 43 also includes alloy metal particles for serving as the matrix of hardfacing 31 the alloy particles are not shown in the photomicrograph of fig3 because.