Thermal stabilizing is a process that is normally only carried out on stainless steel where the steel has previously been chemically stabilized. Welding and other processes containing heat can cause sensitizing of the metal during welding and also in the HAZ (heat affected zone). Thermal stabilization heat treatment occurs by heating the chemically stabilized stainless steel to a temperature where titanium or columbium carbides form preferentially, and chromium carbides do not form. This heat treatment is conducted at approximately at 1625 °F for chemically stabilized stainless steels and the hold time is typically 4 hours.
Some form of protection against sensitizing is to utilize a “L” grade stainless which contains a lower carbon content. However, this is typically only successful in processes where the process has short cycle times that does not allow enough heat to dissipate into the steel. Being in the higher temperature range thermal stabilizing requires similar consideration as other high temperature heat treatments such as annealing.
Canthal heaters should be utilized to ensure the integrity of the heat cycle as much as possible, other QA/QC processes such as heating and cooling tolerances should also be closely monitored. The cooldown period from the higher temperatures varies dependent on final client requirements, there are some who require a controlled cool down and some who require a rapid cool down.
Axiom’s understanding of the process and finite temperature control and measurement associated with Thermal Stabilization heat treatment gives our customers the added confidence that they are working with a company whose commitment to quality processes and procedures sets them apart in their industry. A company driven by quality and safety with the added commitment to getting the job done right, on time and on schedule.