ASTM A553 Type II in the standard ASTM A553/A553M is a kind of Ni alloy steel plates material used to fabric high temperature pressure vessels, the composition of Ni is 8% and 9%. A553 have two types . They are : type I and type II . A553 Type II need to be done the (Quenching + Tempering ) heat-treatment to meet the property requirement in the standard ASTM A553/A553M.