In which data plotter probes gathered material like steel? (13)

'in which data plotter probes' is the definition.
The definition suggests a singular noun which matches the answer.

'gathered material like steel?' is the wordplay.
I cannot really see how this works, but
'gathered' could be 'met' ('meet' can be a synonym of 'gather') and 'met' is present in the answer.
'material' could be 'log' (log is a kind of material) and 'log' is present in the answer.
'like' could be 'y' (similar in meaning) and 'y' is located in the answer.
This explanation may well be incorrect...

Can you help me to learn more?