First of all, to reduce the volume of a piece of brinze by 30% by compression would take centre-of-the-earth pressures; all deformation of metals are, essentially, at zero total volume change.
When one talks of a 30% reduction by rolling or forging, the general meaning is a 30% reduction in the linear dimension inwhich the reduction takes place: a rolling process which takes in 1 cm thick sheet and turns it into .7 cm thick sheet is said to be 30% reduction.
I am not familiar with the terminology of drawing or swaging, but my guess is that it is parallel. Probably someone else can be more definitive.
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Can anyone help me with what is perhaps a rather elementary query?
In bronze metallurgy you often read that a sample has been reduced say 30%
by hammering, or its reduction by cold working can be estimated as 30%. Does
this mean reduced to 30% or reduced by 30%? Is the reduction of volume or
is it linear: I suppose one can be calculated from the other by taking its
square or square root as the case may be. However the reduction is measured
the metal is being squashed together, which must make it heavier in relation
to its volume - increase the object's specific gravity. Does that mean that
you could determine the mean reduction of the whole object by measuring its
weight/volume ratio ? Your metallurgical mounts would show the reduction at
the sampling point, and the specific gravity would measure the average
reduction of the whole object.
David Liversage.
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