| 摘要 |
PROBLEM TO BE SOLVED: To provide a hob made of composite material, the surface of which is hard and has wear resistance, and the inside of which has high tenacity. SOLUTION: At the hole part 12 constituting this hob 10, a metal part 20 rich in metal is provided in the hob-inside, and a ceramics part 22 rich in ceramics is provided on the hob-surface. Between these parts, an inclined part 24 in which the rate of metal component is gradually decreased from the hob-inside toward the hob-surface, is formed.
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