SA553 Type I in the standard SA553/SA553M is a kind of Ni alloy steel plates material used to fabric high temperature pressure vessels, the composition of Ni is 8% and 9%. SA553 have two types . They are : type I and type II . SA553 Type I need to be done the (Quenching + Tempering ) heat-treatment to meet the property requirement in the standard ASME SA553/SA553M.