base metal internal corrosion due to external weldment.

[abangbikerz]

Attached is a picture of a steriliser door where the door arm is welded on the outside to the door. After few years of service( The steriliser use steam to sterilised fruits)the adjacent internal surface of weldment will get corroded. This happen on almost every door that i happen to see. How to explain this corrosion technically?

 

[metengr]

The corrosion is locally on the internal surface because of the heat from welding on the opposite surface where the weld is deposited. Depending on the environment this is common because the heat from welding results in tinting (surface oxidation). To avoid this, you need to remove the heat tint after welding on the inside surface.

 

[abangbikerz]

Thank You metengr. never thought it was so simple.