4.3 Heat treatment after bending
4.3.1 Copper and copper alloy
Copper and copper alloy pipes are to be suitably annealed
after cold bending if their external diameter exceeds
50 mm.
4.3.2 Steel
a) After hot bending carried out within the temperature
range specified in [4.2.4], the following applies:
• for C, C-Mn and C-Mo steels, no subsequent heat
treatment is required,
• for Cr-Mo and C-Mo-V steels, a subsequent stress
relieving heat treatment in accordance with Tab 21
is required.