The Theoretical Optimum Rolling Speed in Powder Compaction
When a metal powder is compacted by rolling, expulsion of the interparticle gas causes a disturbance in the powder bed. This has a fluidization effect and increases with increasing rolling speed; hence, maximum rolling speed is limited. The criterion for optimum rolling speed is taken as that speed below which the velocity of gas expulsion (measured at the coherent-noncoherent interface of the powder in the rolling gap) is just insufficient to promote fluidization. An analysis is presented which shows that the velocity of gas expulsion is proportional to rolling speed, roll radius, and a function of the gripping angle. Methods of increasing the optimum rolling speed are suggested.
KeywordsMass Velocity Rolling Speed Nickel Powder Powder Compaction Roll Radius
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