[MW:6019] Recommended Maximum Heat Input for Low Temperature Carbon Steel(LTCS)

What would be the most suitable Heat input for Impact test at -14 Deg C and -45 Deg. C for Low Temperature Carbon Steel(LTCS) such as A333 Gr6 and A350 LF Cl 2. Is there any reference or guidelines available, please suggest.

 

Also, is it a good practice to convert one product form into another, such as a flange into a pipe and weld this with another pipe to qualify a PQR. Kindly advise. Thank you.

 

Regards,

Sub.