The meaning of 1808: 18 means 20 18, and 08 means the delivery month.
Futures hot coil 1808: refers to the hot coil contract delivered in August 2008+2065438.
Natural person account positions can be held until the closing time of the last trading day in July 20 18 at the latest (of course, positions can also be held until the delivery month if the conditions stipulated by the exchange are met).
Legal person accounts can hold positions until the delivery month.