Abstract: Cast components having reduced porosity levels are produced by pouring a molten metal into a mould which is in a first chamber, and withdrawing the filled mould into a second chamber. The second chamber is then isolated from the first chamber with regard to pressure, and the second chamber is then pressurized with a fluid up to a maximum pressure of 7 MPa for at least part of the time required for solidification of the metal in the mould. The pressure is preferably applied within forty seconds from the finish of pouring of the molten metal, and more preferably within twenty seconds. The still molten state of the metal permits the use of a relatively low pressure to reduce the porosity levels.