99 Diseases of Pressure Equipment: Weld Heat Affected Zone Cracking

Cracks along the toe of a weld are not uncommon during fabrication, and can occur for a wide variety of reasons involving the metallurgy and process control of the the same issues covered above on repair welds can apply to repair welds on castings; especially if you are unaware that the foundry or fabricator is trying to salvage a defective casting by covering up porosity and shrinkage cracking with a big glob of weld metal. Some companies are starting to add specific higher-quality foundries to their “approved supplier” lists, as well as starting to hold valve suppliers (in addition to manufacturers) responsible for the quality of the products they handle. The really interesting “gotcha” in this scenario is that those companies that insist on higher quality castings with their specs and QA/QC usually get them, while the rejected castings go back into the pool to be supplied to other companies that are not paying that much attention to casting quality.

Are you getting someone else’s rejected castings in your valves and pump cases?