a slag rake the steel may be argon stirred during this step to assist in slag removal after deslagging has been completed the ladle 22 is returned to the chamber 10 and a second refining slag which may be the same composition as the desulphurizing slag discussed above is placed on top of the metal this has the effect of retaining heat and enhancing chemical reactions after this second refining slag has been added the cover 12 is replaced and the vacuum reestablished while oxygen is delivered through the lance 25 and argon delivered to the porous plug 22 to promote stirring the second oxygen blow will remove the aluminum in the steel to the desired level of below 0 005 after the second oxygen blow has been completed the lance 25 is retracted the pressure within the chamber 10 may be then reduced from about 20 200 torr to about 1 torr while argon stirring continues this reduces the hydrogen level to below 0 0001 during this second vacuum treatment operation alloy trim additions are made if necessary the metal is then in condition to be transported to the casting machinery the chemical composition of each of the grades of steel discussed above are shown in table i.