How to distinguish between gray cast iron and cast steel?

Gray cast iron carbon mainly crystallizes into graphite and exists in the form of flakes in cast iron, with dark gray fracture surface, making it a common cast iron component. The chemical composition of gray cast iron is generally 2.6%~3.6% C, 1.2%~3.0% Si, 0.4%~1.2% Mn, ≤ 0.3% P, 0.15% S. Cast steel is an important metal structural material with excellent comprehensive mechanical and physical and chemical properties. Compared with cast iron, cast steel has higher strength, plasticity, toughness, and good weldability. If you are referring to these two results, you can use a file to judge them based on their different hardness. You can first find a standard gray cast iron component and then use the same new file to file on the surface of both components. If it feels like the hardness of two pieces is the same, it is judged to be gray cast iron; If the file is judged to be slipping or noticeably harder than standard gray cast iron parts, it is judged to be cast steel.