· KAIPU Engineering · glossary · 1 min read
undefined — Industry Glossary Entry
Definition of the hardness file test in industrial blade quality control: a quick, portable method for verifying blade hardness using calibrated files, the 5-point convention, and the limits of the test.
undefined is a quick, portable method for verifying the hardness of a heat-treated knife, using a set of calibrated files of known HRC values. The test is the standard quality-control check for slitter, shear and granulator blades.
How to perform the 5-point test
- Mount the knife on a flat surface
- Test 5 points: centre, two mid-radius, two edge points
- At each point, try the file one HRC above and one below the target
- The file that “skids” (slides without biting) on the surface defines the upper bound; the file that bites defines the lower bound
Interpretation
- All 5 points within ± 1 HRC of target: heat-treat is OK
- Edge points 2+ HRC soft: decarburisation, surface must be re-ground
- Centre 2+ HRC high: incomplete austenitisation, knife must be re-heat-treated
- All 5 points high: heat-treat temperature wrong, knife must be re-heat-treated
See also: Preventive maintenance schedule (article), D2 vs SKD11 (article).