pfht of cladded dished end

[212197]

I have a cladded dished end of material SA 516 Gr 70 (base material) + SA 240 Gr 304L (cladding).
This cladded dish requires post forming SR.

I am told that when CS vessel with unsterilized grade of ss other than low carbon (e.g. 304/316 grades)is cladded, heat treatment cycle will be :
soaking temp is 510 degree Celsius & soaking time is 10 hours/inch.

Now can any body guide me about soaking time & temperature for SA 516 Gr 70 (base material) + SA 240 Gr 304L (cladding)?

 

[Dhurjati Sen]

Dear,

Carry out PWHT as per UCS-56 of ASME Sec VIII Div 1. Refer UCL 34.

Regards.

DHURJATI SEN

 

[212197]

Dhurjati Sen (Materials),

I am looking for soaking time & temperature for SA 516 Gr 70 (base material) + SA 240 Gr 304L (cladding)?

UCL 34 does not specifically mention soaking time & temperature.

 

[metengr]

Soaking time is 1 hour per inch of thickness of P-No 1 base material, the thermal treatment is subcritical and follows the PWHT temperature requirements for P-No 1 base materials. Cladding goes along for the ride, and is not considered for thermal treatment thickness.

 

[212197]

UCS 56 soaking temp is 595 degree cel. minimum. Generally followed temp for P NO.1 is 630 degree cel.
Whether this temp will have sensitization effect on SA 240 Gr. 304L.? Due to which the temperature is required to be reduced by compensating increased soaking time ?

I am having old specification of client about SA 240 Gr 304 cladded dished end post forming HT. Which calls for reduced soaking temp & increased soaking time.

But do not have same for SA 240 Gr 304L cladded dish. I would like to confirm whether the L grade takes care of sensitization & we do not require to increase soaking time & reduce soaking temp.?

Thanks

 

[Dhurjati Sen]

Dear 2121,

Possibility of sensitization is minimal at 630⁰C with SS304L.

Regards.

DHURJATI SEN