Does curving affect the strength of a section?

The unique processes used at Barnshaws enables the section shape to stay the same after curving. Therefore curving a section within the minimum diameter capacity does not effectively reduce the strength of a section.
When curving under the recommended bending diameter the section shape can change along with the properties associated with that section.

When cold bending a section the mechanical properties will be changed as
follows: the yield and ultimate stress figures will increase. The Charpy and elongation properties will however reduce. This does not cause an issue when used in static buildings.

General bending picture of picture scanner from SCI book.