SA-266-Gr.2 Normalized vs. Q. & T. 1

[luisherrera]

A vessel is in hydrogen service.
The forging´s material is SA-266-Gr.2 Normalized with test in accordance to NACE-TM284 & NACE-TM0177.
Our supplier is ofering Quenched and Tempered instead of Normalized.
I wold like to know if there are advantages or disadventages using this material in Quenched and Tempered instead of Normalized heat treatment.

Tanks in advance.

 

[metengr]

Per ASME SA-266, you have several heat treatment options for this material; annealed, normalized, and normalized and tempered. If agreed upon between the purchaser and supplier, liquid quenched and tempered heat treatment can be supplied.

Normally, a liquid quench and temper heat treatment is required on material that is of a thickness or geometry to assure meeting thru thickness mechanical property requirements, where a normalization heat treatment may not achieve the required thru thickness mechanical properties.

Advantages of Q&T; a consistent, thru thickness structure that produces more uniform mechanical properties, and increased toughness.

Disadvantage; potential distortion concerns from liquid quenching, increased cost for this heat treatment and more care during welding fabrication to keep heat inputs from adversely affecting the quenched/tempered bulk material properties.