100 x 100 Books # 72 - Heat Treatment

[BornToSin]

[link Point to another website Only the registered members can access]

[amitrajmane]

Dear BornToSin*

Thanks & Regards*
Amit

[rioca57]

[link Point to another website Only the registered members can access]

Dear friends* I have problems of Stress Corrosion *****ing and Embrittlement in body plates (Shell* thickness = 17 mm* SA-285 Gr C) and head (Cap.* Thickness = 19 mm* SA-285 Gr C) of a pressure vessel handling an alkaline solution in the Expansion Cooling area of an Alumina Plant through the Bayer Process (130 grs./lts. sodium hydroxide at a temperature between 80 ° C and 85 ° C).

The abnormality is caused by an inadequate chemical washing practice with highly concentrated LC (caustic liquor or sodium hydroxide) between 300 and 350 grs./lts. At temperatures between 90 ° C - 95 ° C* to release internal encrustations in the pressure vessel* however* this practice was done at the boundary of the alkaline attack on the metal wall by SCC (Stress Corrosion *****ing).

I ask:
1) To demonstrate the Caustic Fragilization techniques of Non-destructive Tests I can apply to the plates of the pressure vessel (I had in mind the Metallographic Replica)
2) If the metal is Fragile as I can make the repairs (in fact if it is Fragile* I understand that in correcting the material of the plates they will ***** more)
3) If prior to repair* make a thermal relief prior* the metal of the plates of the pressure vessel will admit weldability without *****ing.
4) Before this situation I can make a previous thermal relief* then I correct and later I am relieving thermally again.
5) Who could give me a technical recommendation according to Standards or will have to do the container again (there are opinions on the plant that the pressure vessel can be saved)
Very grateful for any comments

[rioca57]

*****ing = *****ing y * = *

[rioca57]

*****ing = agrietamiento