Heat Treatment is required for cold forming head

According to UG-79 Heat Treatment is required for cold forming heads when:

A - Extreme Fiber Elongation is more than 40%

B- Fiber elongation is more than 5% and any of the following condition exist:

  • Impact Test is not exempted according to UCS-66
  • Heads for lethal service vessel as restricted in UW-2
  • Head plate thickness before forming is 16 mm
  • Thickness reduction at any location after forming is more than 10% of actual thickness where extreme fiber elongation is more than 5%
  • Forming Temperature between 120-480 deg. C

You may calculate fiber elongation from formula given in Table UG-79.1 or better to consult with pressure vessel designer for this calculation.

(Heat Treatment when applicable will perform by following UCS-56 requirements)

Hot Formed heads in no case does not require heat treatment after forming.

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