SA387 Gr. 11 NT vs.NACT

[Sanchinarro]

This is a plate specified as SA387 grade 11 normalized and tempered. Vessel is in high temperature, hydrogen service. Plate thickness is 150 mm.
The supplier of the plate (industeel) is ofering this plate but the heat treatment is normalized, acelerated cooling and tempered. This heat treatment is allowed by ASME material specification but "when permitted by the purchaser". Industeel says that to get material properties for the required thickness he requires this heat treatment and so, material has better material properties than ASME requires.

I would like to know oppinion or experiences about advantage/disadventages of NACT vs NT using this steel.

Thanks in advance.

 

[metengr]

No issues regarding the normalized and accelerated cooling.

 

[metengr]

I might add that I had reviewed a year or so ago a copy of the Industeel presentation from the API Roundtable held in Atlanta, GA. The process used by Industeel for their heavier steel plates, supplied as SA 387 Gr 11 Cl2, were either listed as Q&T or NACT. Their test results showed similar tensile properties between a Q&T and NACT.