Carbon Steel and Corrosion
Date: Fall 2013
Why low carbon steel materials have poor resistance to corrosion?
In fact, all types of plain carbon steel (both low carbon steel and high
carbon steel) have very poor resistance to corrosion. Both types of
materials are just pure iron with a little carbon. Even high carbon steel
has not much more than 1% carbon, which does nothing to improve its
resistance to corrosion.
The corrosion (or rusting) of iron and steel is a complex process that
requires moisture and the presence of oxygen. Have a look at
http://en.wikipedia.org/wiki/Rust for an explanation of the mechanism of
corrosion of iron and steel.
Generally, carbon-steel have low carbon content - about 1% by weight. These levels of addition of carbon does not result in a significant difference in the corrosion resistance of iron. The carbon is simply added to increase the strength of the object, rather than to increase its resistance to corrosion.
Greg (Roberto Gregorius)
Thanks for the question. There a couple of general answers to your question. The specific answers depend on the specific type of alloy in question. The ability to resist corrosion is due to the arrangement of atoms in the alloy as well as how neighboring atoms are held together. All materials (metals and alloys) will corrode under certain conditions--these conditions can be mild or very aggressive. In order to begin the corrosion process, atoms need to be removed from the bulk material so that a defect occurs. If you can keep this defect from occurring, the material will resist corrosion.
I hope this helps.
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