Serious cracks were found at tube-to-tubesheet welds during the start up operation of a cracked gas/steam heat exchanger in a gas plant. The cause of the failure has been analyzed, and the
Feb 15, 2007 · The program began with NDE, followed by crack removal, preheating, welding, post-weld heat treatment, and final machining of the tube stub-to …
has cracks as determined by NDE, installation of a flush patch Use NBIC local post weld heat treatment The National Board of Boiler and Pressure Vessel Inspectors 18. HEAT TREATMENT The National Board of Boiler and Pressure Vessel Inspectors 20. NBIC Part 3 Alternatives to PWHT
SUMMARY. The problems of in-service cracking of weld zones can be minimized by attention to the important factors summarized below. Preheat or postweld heat treat weld joints that may develop a hard HAZ when corrosive conditions are met. Inspect weld HAZs for cracks by a suitable NDE method if hard HAZs are suspected.
Jun 01, 2002 · X-20 weld joints are given complex cycles of pre-heating and post-weld heat treatment to avoid cracking and to ensure that correct mechanical properties are achieved. The resistance-heating method was found to be inadequate for post-weld heat treatment of X-20 joints.
Understanding Weld Cracking, Its Causes, Consequences…and
Tubesheet Repair - National Board of Boiler and Pressure
relief treatment may be necessary when fabricating high-ly restrained members. Centerline Cracking Centerline cracking is characterized as a separation in the center of a given weld bead. If the weld bead happens to be in the center of the joint, as is always the case on a sin-gle pass weld, centerline cracks will be in the center of the joint.