The local material condition can differ from an unchanged nominal alloy label.
Retain the local mechanism
TWI describes chromium-carbide precipitation near austenitic stainless grain boundaries during a welding thermal cycle, with adjacent chromium depletion. That sensitization question concerns local condition as well as composition. Primary reference: TWI technical explanation.
A bulk composition record averages material over its stated sampling boundary. It cannot alone describe the detailed distribution at a thermally affected grain boundary. Keep nominal alloy identity and local thermal-history evidence as separate records.
Compare hypothetical document sets
Imagine two fictional assemblies have the same declared nominal stainless grade. Set A includes only its material certificate. Set B also contains thermal-history and relevant local-material assessment records for the welded region.
The additional records address a question the shared grade label leaves open. They do not automatically show that B is sensitized or that A is unaffected. Neither set is an actual HM case or an alloy-selection recommendation.
Request evidence at the relevant region
Prepare fields for parent grade, weld-region location, thermal history and the method supporting any sensitization conclusion. Keep a proposed corrosion-performance inference separate from the observations used to support it.
Ask which local condition matters under the actual exposure and what evidence addresses it. Surface staining, deposited iron and grain-boundary depletion are different hypotheses. The worksheet helps frame a material review without declaring that every weld loses corrosion resistance or that a clean-looking surface proves unchanged local metallurgy.
Customer Questions
Does an unchanged grade label establish the local condition?
The welded region can need its own thermal-history evidence.
What local feature does the cited mechanism concern?
Chromium depletion adjacent to grain-boundary carbides.
Do the fictional documents prove sensitization?
They distinguish the evidence scopes, not an actual result.
Primary References
These references support the technical principles discussed in this guide. The worked examples and review questions are educational.
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