| 摘要 |
<p>Low-cost articles characterized by a surface of revolution, such as truncated spherical balls, e.g., plain spherical bearing balls, are provided made by the powder metal compaction and sintering of blanks followed, in the case of ball elements, by densification of the outer spherical surface by mechanical working, such as by roll-forming, the balls so produced being characterized by improved sphereicity and dimensional tolerance and improved wear resistance combined with optimum resistance to corrosion. The spherical surface of the ball is substantially free of pores, has a work hardened structure and has a density at and adjacent the surface of at least about 95% of the theoretical density of the metal, the density substantially below the surface co being less and ranging to as low as at least about 70% of theoretical density.</p> |
