Have somebody worked with the material specification SA 302 Gr B?
Is there any special recommendation about the Pressure Vessels fabrication (conformation , welding, heat treatment,...) using this material specification?
The SA-302 grade B material you specified is basically a carbon steel material alloyed with magnesium (1.62% max) and molybdenum (.60% max.) P-3 group 3 material.
Fabrication requirements are listed in section UCS of Section 8. P3 grade 3 materials of all thickness are required to be PWHT UCS-56. PQR and WPS will need to be qualified for PWHT. Full RT is required for nominal thickness above 3/4" per UCS-57. See UCS-66 for impact testing requirements.