Special consideration may be needed in the formability section of a specification, in light of the ultimate part configuration and bends required to achieve that shape. Ideally, the axis of each bend should be oriented transverse (90°) to the direction of rolling direction. In practice, compromises to this rule are often necessary. For example, the bend axis may be altered from the ideal for blanking economy, to minimize scrap. If the part will receive several bends at various angles, it must be oriented for the best overall result.
This figure illustrates how selection of the blanking angle will affect bend axis, and can be manipulated to yield the most desirable bending angle. It is recommended that critical bends be oriented a minimum of 30° to grain direction; more if possible.
Blanking and bending angles in relation to grain flow in steel strip
This figure shows formability of AISI 1050 strip of varying hardness, and different degrees of bend axis orientation to rolling direction.
Effect of hardness and bend axis to
rolling angle on formability of AISI 1050 strip