The heat treatment is mainly for carbon steel screws, mainly for quenching and tempering heat treatment and carburizing heat treatment to meet the screw strength requirements of different environments.
1. Quenching and tempering heat treatment: The products of grade 8.8 and above are graded and heat treated. This heat treatment is characterized by a uniform hardness inside and outside.
When the same material is heat treated, the higher the hardness, the worse the toughness. Therefore, it is necessary to have a safety match, and the toughness is also guaranteed while satisfying the hardness.
2. carburizing heat treatment: self-tapping screws type screws basically need this treatment, the characteristics are that the surface is very hard, and the core is relatively soft; because it is necessary to attack the hard iron plate.
Self-tapping screws are more risky. For example, self-tapping screws often encounter broken ends. The possible reasons are: 1 hydrogen embrittlement; 2 hardness is too high or too low to cause twisting; 3 cross groove is too deep; 4 head is too thin 5 head-neck joint without R angle causes stress concentration; 6 operation is not standardized.
