| 摘要 |
A button and a rock drill bit (30, 50) for percussive drilling comprising a bit head (39) configured to be attached at an end of a drill element (33, 53) of a drilling assembly, said bit head having at a front end (38, 60) as seen in the intended drilling direction a plurality of buttons (41, 42, 56, 59, 80, 90) distributed over said bit head and configured to engage material to be crushed, at least one of said buttons having a shank portion (41', 56', 80', 90') of a substrate material, comprising particles of a first material embedded in a binder phase, said first material being harder than the binder phase. The shank portion (41', 56', 80', 90') comprises at least partially a bearing portion, the material of which is harder than the binder phase. At least one of said buttons (41, 42, 56, 80, 90) is allowed to rotate about its own symmetry axis.
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