Meaning
Technical delivery specifications that define the ultrasonic testing methods for forged or rolled steel products are used to ensure internal material soundness. Adhering to SEP 1921 ensures that tool steel blocks and bars are free from internal defects like cracks, shrinkage cavities, and large non-metallic inclusions. This standard applies to steel products intended for highly stressed mechanical components and manufacturing tools.
It does not govern the surface quality or surface-crack detection of the materials under evaluation.
Testing Method
Pulse-echo ultrasonic probes scan the metal to detect internal acoustic reflections that indicate discontinuities. Applying the SEP 1921 protocol ensures that internal voids or inclusions are identified before the material is processed into expensive tooling.
Quality Grade
The standard organizes testing requirements into specific classes based on the size and frequency of the detected defects. Specifying a strict SEP 1921 class ensures that the purchased tool steel has a highly homogeneous microstructure free of weak points.
Tooling Application
Internal defects in tool steel can lead to catastrophic cracking under the high cyclic stresses of stamping or deep drawing. Verifying materials against the SEP 1921 standard prevents the waste of machining resources on steel blocks that contain internal flaws.
