| 摘要 |
PURPOSE:To accord sufficient corrosion and abrasion resistance and to make it unnecessary to provide a padding on the whole surface of a screw, by using a specific metal as a body material and forming a crest member made of a specific alloy along a connecting part set continuously and spirally on the base material. CONSTITUTION:A highly corrosion and abrasion resistant screw 1 is prepared of a body material 2 made of a precipitation reinforcing type Ni-based alloy. A crest member 3 made of a Ni-based alloy whose hardness is higher than that of the body material is formed by means of a powder padding welding along a connecting part set continuously and spirally on the body material 2. The reason why a precipitation reinforcing type Ni-based alloy is used as the body material 2 is that this alloy exhibits excellent corrosion resistance and at the same time has a hardness embodying a sufficient abrasion resistance as the body material for the screw. By using the precipitation reinforcing type Ni-based alloy as the body material 2, it is possible to omit a padding on a root. On the other hand, the angle member 3 is formed of the Ni-based alloy whose hardness is higher than that of the body material by means of the powder padding to give importance to abrasion resistance. |
