HEAT TREATMENT OF PIPES II

At all stages of the heat treatment process, the temperature must be accurately monitored and recorded by a thermocouple or other suitable, approved method, to guarantee that the temperatures specified in the WPS are adhered to during the welding process. When necessary these temperatures must be recorded.

Where hardness tests of production welds are stipulated to verify satisfactory heat treatment, the hardness limit applies to the weld and to the heat affected zone tested as close as practicable to the edge of the weld.

The heat treatment of welded joints between dissimilar ferritic metals or between ferritic metals using dissimilar ferritic filler metals should use the higher temperature specified in ASME B31.3, Process Piping Table 331.1.