The holding time of the test piece shall be no less than 80% of the total holding time of the welded part during the manufacturing process
Thread Content
Excuse me! We have a product that consists of a tube sheet, tube plates, and a casing, all of which require stress-relief heat treatment: 2 hours for the tube sheet, 5 hours for the tube plates, and 3 hours for the casing. According to standard 47014, the holding time for the test pieces must be no less than 80% of the total holding time experienced by the welded parts during manufacturing. So, is the minimum holding time required for process evaluation 0.8 * (2 + 5 + 3), that is, 8 hours? Our designers, however, say that the insulation time for process evaluation should be calculated based on the component in the equipment that requires the longest heat treatment time; that is, 0.8*5, which equals 4 hours
The total insulation time refers to the sum of the times spent on multiple heat treatments, not the sum of the cleaning times for each individual component
So, the evaluation can simply be based on the 5-hour period for the tube sheet?