Wee-e-e-e-l-llll - depends how far you want to go.
Thermit Welding *used* to formulate and make up powders to order, to
cast just about any grade of iron r steel.
Basically aluminium powder and iron oxide, traces (or more) of other
metals are added.
You make yur mould (usually oily sand, Petrabond, or similar, and set up
the crucibles provided, accrding to instructions.
The powder is ignited using a fat stumpy sparkler, and when it has
cooled sufficiently the molten metal is tapped to run into the mould(s)
when the colour of the crucible in the clear half of the viewer
(provided) matches the red of the coloured half.
The result can then be machined to suit.
(I used to work in 'The Tantalum', a shop not a hundred yards from
Thermit, back in the '70s.)
--
Old Nick