Post-Weld Heat Treatment Log
A post-weld heat treatment protocol is a documentation of the temperature-time history during an annealing treatment. It serves to prove the correct execution of stress relieving or hardening and tempering.
Physical-Chemical Mechanism of Action
The post-weld heat treatment (PWHT) log records the temperature and time during which a workpiece is held in a furnace. This process affects the metal by altering its chemical composition and mechanical properties.
Metallurgical Relevance & Welding Risks
A correct PWHT log is critical for weld quality. Wrong temperature or time can lead to insufficient stress relief, causing cracks and distortion. A missing log can also create legal issues.
Workshop Practice & Instructions
To properly maintain a PWHT log, follow these steps:
1. Record the furnace start and end temperatures.
2. Document the time the workpiece is held in the furnace.
3. Use an accurate temperature measuring device.
4. Store the log in a safe place for future reference.