ISO 10113:2006 specifies a method for determining the plastic strain ratio, commonly called the r-value, of flat metallic materials, typically sheet and strip. Plastic strain ratio is the ratio of the true width strain to the true thickness strain in a test piece which has been subject to uniaxial tensile stress.
To calculate the r-value a test is performed to ISO 6892 and using an axial and transverse extensomers. Where the true plastic width strain against true plastic length strain is homogeneous a single data point method can be used, with a inhomogeneous deformation a statistical method can be used. These calculations can be done automatically using Bluehill ® * or Partner software.
An ISO 10113 test is typically performed at the same time as ISO 10275, tensile strain hardening exponent.
*Bluehill 2 or Bluehill 3