Heat Treatment / PWHT Requirements 1

[Shmulik]

1. How should I understand the requirement of UCS-79 (d) for heat treatment: is the resulting extreme fiber elongation of more than 5% condition stands alone to request component's heat treating, or it is only required when any of the conditions 1 ÷ 5 is been added to it?
2. Is HT required when any of the conditions 1 ÷ 5 exists with no more than 5% fiber elongation?
3. Is HT of heads should be separately preformed according to UG-79 when the entire vessel is going to be post weld heat treated according to UCS-56 ?

Thank you very much in advance.

 

[metengr]

Shmulik;
My interpretation of UCS-79 in ASME Section VIII, Div 1 Part C is as follows;

1. The word AND in paragraph d) indicates greater than 5% fiber elongation after cold forming in conjunction with ONE of the five conditions (1-5).

2. No. Paragraph d) refers to cold forming of the item and subsequent heat treatment.

3. No. If the manufacturer is fabricating the entire vessel (supplied shell courses, heads and welding)you can take credit for the heat treatment required in UCS 79 when the entire vessel will be subjected to post weld heat in accordance with the requirements in UCS-56.

 

[deanc]

If you buy heads--Make sure you get the paperwork!