A piece of 1018 steel will obtain virtually no hardness from a heating & oil quenching. Carbon steel does not really begin to respond to heat treating until around a 1030 steeel & at this carbon level a water quench would be normal.
1018 steel is subject to being "Surface" hardened through Carborizing (AKA Case Hardening) but is not a through hardening steel.


Miller/TN
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