The manufacturing of thick-wall components, such as shells, for petrochemical reactors normally requires the 2.25Cr-1Mo (SA 336 F22) steel. This paper deals with: 1. Experienced difficulties in producing thick-wall forgings up to a thickness of 500 mm with standard 2.25Cr-1Mo steel. 2. The solutions offered by Le Creusot Heavy Forge.

The studies discussed are: (1) the effect of the structure; (2) the effect of the chemical composition on hardenability and temper embrittlement in steel making; and (3) the effect of austenitization conditions.

Some examples concerning industrial forgings are presented, among them: 1. The manufacturing of shells for the petrochemical industry. 2. A thick-wall shell from a 146-metric ton hollow ingot.