The surface looks like sponge in places on some of the steel plates that we
are buying. These are about 80 inches wide and about 0.5- 0.7 inch thick
plates. The grades are X60 and X80 type with Columbium and Vanadium for
microalloying. Any ideas or references on this surface quality issue?
"Spongy surface - A porous and cracked surface caused by oxidized
subcutaneous blowholes." Definition from "surface Defects in Ingots and
Their Products (Recommended Definitions),Special Report No. 63, The
Iron and Steel Institute, London, 2nd edition, 1958
Subcutaneous is a fancy word for 'beneath the skin' and blowholes are
holes caused by gas entrapped during solidification.
We don't believe what we write, and neither should you. Information
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may not be worth any more than either a groundhog turd, or what you
paid for it (nothing). The author may not even have been either sane or
sober when he wrote it down. Don't worry, be happy.
This kind of problem was very common in semi-killed steels, but this
kind of steel is no more produced, since practically all steel slabs
are continuously cast nowadays. Perhaps this problem can be due to hot
shorteness caused, for example, by the presence of a excessive
residual Cu content.
All the best,
Antonio A. Gorni