First, lets make an antique looking steel.
Load STAINED SILVER, good start point.
Change the COLOUR production function, from Basic Repeater, to Filtered
Fractal, Cellular, Vornoi. Largest feature 10, smallest 0. Roughness
Remove the link to Colour output. Add a Maths function: Multiply
(by about 0.25 or so)
Link this to Colour.
Now for the BUMP, add a texture node, and look for a texture. You
want something elongated, lined. Best one is actually some barks,
or if not make one using thin lines mostly in one direction, add
some small blotches, blur it all. Hand made iron/steel has patina
and lines from work/grain and folding.
Then set the SCALE of colour and Bump to 0.1
This should give a nice non-regular, look to the metal.
Set the Depth of the bump to about 0.85. Save your