Definition - What does Gouge Hardness mean?
Gouge hardness is a measurement that is used to determine the resilience of a coating by way of a specific measurement tool known as a pencil hardness gauge. During the test, different pencils are scratched along the surface of the coating to determine which one is hard enough to gouge the coating.
Gouge hardness is a measurement that is vital to understanding the ability of a material to resist removal due to excavation. Coatings intended to prevent corrosion have different gouge hardness requirements depending on the environment where they are applied.
Corrosionpedia explains Gouge Hardness
Gouge hardness is very similar to, but often considered different than, scratch hardness. Gouge hardness is commonly determined by the hardness of the pencil required to cut into the coating for a certain distance. Scratch hardness is determined by the hardness of the pencil that leaves any scratch whatsoever on the coating. Unless they have the same hardness value, scratch hardness is generally less than gouge hardness.
There are many pencil hardnesses that are used to determine just how hard a material must be to gouge the coating. It is common for 6B to be the softest pencil in a pencil set used to test gouge hardness. The pencils then increase in hardness as they go from 6B to 5B to 4B and so on, until they reach a single B. Then hardness continues as the pencils go from HB to F to H to 2H to 3H all the way up to 9H. The 9H pencil is normally the hardest in the set of pencils used for gouge hardness testing.