| 摘要 |
A method of forming an article e.g. a bearing assembly A by bonding together two or more members formed from powdered metal, comprises forming a first member 10 having the desired configuration from an iron base powdered metal containing a sufficient amount of copper to cause the member to expand upon sintering, forming a second member 12 into a configuration such that it is adapted to engage in an interference fit with at least part of the first member, the second member being formed from an iron base powdered metal containing a sufficient amount of nickel to cause the member to shrink upon sintering, fitting the second member to the first member to form an interference fit therewith and such that on sintering the first member expands against the second member which, in turn, shrinks against the first member, and heating the assembly of the first and second member at a sintering temperature which is sufficient to cause the members to become metallurgically bonded together. Preferred compositions for the copper and nickel bearing powders are, respectively, by weight, Fe 93-96%; Cu 3-6%; C 0.5-1% and Fe 95-97.5%; Ni 2-4%; C 0.5-1%. <IMAGE> |
