Hi Palmeto,

When you say hardness value, I presume you actually mean ductility. The hardness measurements (Vickers, Brinell etc) are a separate issue again.

With regard to the reduction of area, it is the same for any tensile test. However the preparation of samples for tensile testing of induction bends is difficult because your samples have curvature in two axes.

Acceptable values for reduction in area are entirely at the discretion of the purchaser. They will specify the mechanical properties that they wish to achieve and the induction bending company will formulate a manufacturing procedure in accordance with ISO 15590-1 or ASME B16.49 which achieves the desired properties. It is typical to try to bring the material back to that of the parent material (pipe) specification.

An example would be API Specification 5L X70M PSL2 welded; here we would aim to achieve the same properties as specified in the linepipe specification by applying the requirements of ISO 15590-1. ISO 15590-1 deals directly with ISO 3183/API Specification 5L so they are a natural fit for each other.

I also apologise for the long delay, I have been on vacation.