Heat Treatment of End plates after coldforming ASME or EN12953

[wkmtcc]

I tried to find some requirements regarding the heat-treatment of a cold formed end plate with a knuckle radius of 80 mm and a wall thickness of 18 mm. I found some hints about normalizing but at the same time i found also some requirements regarding stress relieving. The end plate is used on a smoke tube boiler.
Now we are not sure what kind of heat treatment we have to apply.
Wolf

 

[Mec.tec]

Is it an end plate or a dishend?
What is the design code?
See PG-19 in case of ASME SEC I.

 

[wkmtcc]

The Design Code is actually EN12953.its a flat end plate.the flanging is produced by spinning with a knuckle radius of 80mm, cold formed. The code is not clear but it looks like that the heat treatment should be done by normalizing. But again no clear guideline. The problem now is that the manufacturer did only stress relieving I m puzzled.