There isnt an intrinsic method of dating metal as there is for wooden objects such as radiocarbon-dating or tree-ring dating. Much depends on the assessment of the object. For instance, an axehead made of bronze is likely to date from the Bronze Age, before knowledge of how to make iron.

Can you date iron?

Iron artefacts are generally dated by association or on stylistic grounds. If the fuel is of a material containing contemporaneous carbon, i.e. has an ambient radiocarbon signature, e.g. charcoal, then we may reliably radiocarbon date the artefact by extracting this carbon.

Can metal be radiocarbon dated?

For radiocarbon dating to be possible, the material must once have been part of a living organism. This means that things like stone, metal and pottery cannot usually be directly dated by this means unless there is some organic material embedded or left as a residue.