The hardness test of the paint film is tested according to the national standard GB/T6739-2006, and the hardness of the paint film is measured by the pencil method. The test steps are as follows:
(1) Prepare a pencil of 6B, 5B, 4B, 3B, 2B, B, HB, H, 2H, 3H, 4H, 5H, 6H, cut off 5-6 mm of the pencil with a knife, and sand it with 400-grit sandpaper The core of the pen is ground so that the end face is relatively flat but the edges are sharp.
(2) Install the pencil on the Hardness Tester and lightly place it on the surface of the coating to be tested;
(3) Hold both sides of the pulley with your hands, and push it forward at a certain slow speed, generally about 8 mm forward, and you can push it once, and you cannot drag it back and forth;
Note: Start with the pencil with the highest hardness, and then replace the pencil with gradually reduced hardness. Each pencil will draw 3 scratches with a length of about 8 mm until the coating film is not damaged. The hardness of this pencil is the hardness of the coating film.
