Friday, September 2, 2011

Superrfined Structural Steels

The Strength of ordinary structural steels is increased by raising their carbon content, which has an adverse effect on other mechanical properties. Better mechanical properties are obtained by age hardening, by thermodynamic treatment and by ensuring that there are virtually no non-metallic inclussions. Structural steels may be alloyed or unalloyed.

Free cutting steel (mechining steel)
Free cutting steel are unalloyed or low alloyed high grade steels. They are used for workpieces produced by automated processes, and must produce short chips (type class 07).

The good machinging characteristics are largely the result of a fairly high sulfur content (up to 0.2%). The sulphide inclusions result in brittle chips. The addition of lead improves surface quality.

The example of this kind of steel are 10 S 20, 11 SMn 28, 11 SMnPb 28.

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