The microstructure of
a steel has a significant effect on the strength of a steel. For a
steel with a certain composition the microstructure can be altered
through varying the processing route used. For example for strip
steels the coiling temperature can be controlled to give varying
microstructures in the final coil with varying properties. Review hot rolling of strip steels for
more information.
In this example, different
yield strengths can be achieved for a fixed composition by obtaining
different microstructures. Drag the appropriate cooling procedure
box to the correct location.
Changing the amount of second phase in a predominantly ferritic
microstructure has a pronounced effect on the strength of
the steel. This microstructural change can be achieved through
control of composition and processing as mentioned earlier.
For structural steels produced as plate
and sections with a ferrite + pearlite microstructure relatively
small changes in the amount of pearlite
and ferrite at low levels (~5-10%) have a relatively small effect
on the strength level, especially the yield strength as the
surrounding ferrite yields first anyway.
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