What is meant by Post Heating?
Post-heating refers to the maintenance of preheat after the weld has been completed, to allow increased rates of hydrogen evolution from the weld to occur. The Post-Heat temperature may be the same as, or greater than, the original preheat temperature specified.
What is the purpose of Post-Heating?

Post-heat requires full control over time and temperature, to be effective in the removal of hydrogen from the weld, and controlled techniques incorporating thermocouples are preferable.
Why is Post-Heating important?

Hydrogen bake-out is a technique closely related to post-heat. Post-heat is a fabrication hydrogen evolution process. Hydrogen bake-out is usually done during repair or modification of a component which has seen service in a hydrogen environment, to reduce the hydrogen that has been introduced in service, before attempting to weld the component. Hydrogen release is a term often used to refer to both or either of these processes.

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