Steel Industry Glossary
- Grain Flow
- The direction the worked metal fibre runs in a finished part, and the main reason to forge rather than machine from bar.
- Hardenability
- How deep into a section the hardened structure forms on quenching — the reason heavy forgings use alloy rather than carbon steel.
- Magnetic Particle Inspection
- Surface and near-surface crack detection on ferromagnetic forgings using a magnetic field and iron particles.
- Normalising
- Heating above the transformation temperature and cooling in still air to refine and homogenise the forged grain structure.
- Quench and Temper
- Hardening by rapid cooling from austenitising temperature, then tempering back to the ordered strength and toughness.
- Reduction Ratio
- The ratio of starting cross-section to finished cross-section — the measure of how much the metal has actually been worked.
- Ring Rolling
- Growing a pierced doughnut into a seamless ring between a driven roll and a mandrel.
- Stress Relief
- A sub-critical soak that removes residual stress from forging, welding or rough machining without changing the properties.
- Ultrasonic Testing (UT)
- Volumetric inspection of a forging to ASTM A388, with an acceptance class agreed before forging.
- Upsetting
- Compressing a billet along its axis to increase diameter and reduce length — the first operation in making a disc or a ring.