| 摘要 |
PROBLEM TO BE SOLVED: To keep the breakdown performance for a long time by an arrowhead made of a steel material and capable of being vibrated by a driving means for applying the impact to a matter to be broken, by connecting a spire member, having a tip made of an ultra hard material and fixed on its point, with a rod member for supporting the spire member as a separated body, demountably, including the peak member with the rod member. SOLUTION: This arrowhead 1 is formed by tapering one end of a member made of a steel material, and a tip 6 mounted on its point part 4 is a long rod or linear member made of ultra hard material such as WC-Co alloy and the like, and is buried into an insertion hole 8 formed on the point part 4 with an adhesive, and fixed in a state that its point is projected. The ultra hard material is materials harder than the steel material of the point part 4, and superior in the abrasion-resistance, strength, hardness and toughness, such as alloy steel such as Co steel, Mo steel and the like, super hard alloy prepared by blending Co, Ni and the like into metallic carbide such as WC, TiC and the like and sintering the same, cermet, ceramic, silicon nitride sintered material and the like.
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