a method of producing a chilled iron camshaft from a chromium containing cast iron is described . the cast iron material contains between 0 . 5 wt % to 1 . 2 wt % of chromium . the camshaft having a white iron structure adjacent chill inserts in a casting mold and a grey iron structure in substantially all other regions remote from the chills . the method comprising the steps of assembling a sand casting mold having a camshaft shaped cavity and also having chill inserts adjacent the cavity regions where white iron is desired . preparing a molten metal charge of cast iron having a carbon equivalent lying in the range from 3 . 5 up to 4 . 0 wt % and adding sufficient nucleant prior to pouring to fill the mold cavity , to ensure that under cooling of residual liquid remaining after solidification of the white iron structure adjacent the chills remains above the iron - cementite eutectic temperature prior to solidification into grey iron .