| 摘要 |
A bi-metal drill bit (10) includes a body defining a cutting end (12) and a shank end (14). At least a portion of the cutting end (12) is formed of a first metal section (16) and at least a portion of the shank end (14) is formed of a second metal section (18) that is welded to the first metal section (16). The first metal section (16) has a first metal having a material hardness that is higher than a second material hardness of the second metal section. The first metal section (16) has a length to diameter ratio (L/D) between approximately 0.7 and approximately 3.0, or at least one of the first and second metal sections (16, 18) have been heat treated so as to have a recognizable different appearance than the other of the first and second sections (16, 18). |
