For a generic martensitic nickel-chromium white cast iron, with composition ranges equal or slightly broader than for ASTM A532 Class 1 Type A,
CTE = 8-9 x 10-6 m/m/oC for a temperature range 10-260oC
= 4.4-5 x 10-6 in/in/oF for a temperature range 50-500oF.
From ASM Metals Reference Book, 3rd Edn., pp. 270-271.