سلام.
لطفا متن زیر را ترجمه نمایید.
There are two main impurities in molten
aluminium, non-metallic inclusions and
dissolved hydrogen. Dissolved hydrogen
is arguably the most difficult impurity to
manage in the production of aluminium
castings. The initial levels in the molten
alloy can vary due to the type of furnace
charge and atmospheric conditions,
excess hydrogen can cause porosity and
insufficient hydrogen can cause shrinkage
in the finished casting. Often the optimum
level of hydrogen in the molten alloy is
specific to particular castings and
production processes and is not
necessarily the lowest level possible.