Steve,
Thanks for the response.
Forget to mentioned the forging thickest section is 200 mm. According to a number of suppliers we talked to that is the reason a CE 0.44 is needed.
Regarding the other aim of the CE restriction as you mentioned
"...may also be a means of controlling material...
My client asks for a carbon equivalent CE(IIW) of 0.40 for F65 forging flanges with the thickness of the weld neck of 25mm.
My supplier can not provide that CE and instead offers a CE of 0.44 (carbon content of 0.16%).
As far as I know, higher carbon equivalent means that the steel is less...