| 摘要 |
PURPOSE:To enhance the strength of joint with core by placing a molded body of ferric base powder in the center of a negative die and by filling it with powder consisting of tungsten etc. CONSTITUTION:Super abrasive grain 2 is lightly attached to a circular surface of a negative die 1, and in its center a circular molded body 10 of ferric base powder with specified dimensions is inserted, where metal dust 5 with good heat and abrasion resistance such as tungsten shall fill the space between the surface 2 of this negative die 1 and the outside circumferential surface of this molded body 10, over which an infiltrating material 6 is placed, whereafter the whole is heated to exceed the melting point of this infiltrating material 6 to melt the infiltrating material 6 which is then infiltrated into gaps between powder particles of the molded body 10 and the metal dust 5. Thereby the strength of joint between the outer layer of base metal formed through sintering of tungsten powder etc. and the inner layer of the core formed by the molded body of ferric powder. |
