Is normalizing required after spin-forming 34mm Q345R plates into heads?
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Since the 34mm Q345R plates are supplied in the normalized state, the manufacturer carries out a certain degree of annealing during the production of the heads to facilitate spinning. Is it necessary to perform normalization again to restore the properties of the plates after such treatment? Note: This device is not subjected to heat treatment as a whole.
If the annealing heat treatment does not damage the normalized state, no normalizing is required; otherwise, the head needs to be normalized again
The stress-relief annealing temperature for Q345R is around 640 degrees. This temperature is below the material’s phase transition point of 720 degrees, so the microstructure is not damaged and no re-tempering is required. http://bbs.hcbbs.com/viewthread.php?tid=765468 http://bbs.hcbbs.com/viewthread.php?tid=609912 Two posts for reference
What the original poster is referring to is annealing carried out before spinning, in order to reduce the spinning strength; however, I believe it still falls under cold spinning, as internal stresses are generated during the spinning process. Therefore, stress-relief annealing is necessary at least, and normalizing would be even better.
It is the annealing treatment done before spinning, rather than temperature control during the spinning process.