The tail of the self-drilling screw has a tail-drilling or pointed tail shape, and no auxiliary processing is required. It can be directly drilled, tapped and locked on the set material and basic material, which greatly saves construction time. Compared with ordinary screws, its toughness and holding force are high, and it will not be loose after a long time after combination. It is easy to complete the operation by using safety punching and tapping at one time.
Purpose: It is a kind of screw, mainly used for fixing the color steel tile of steel structure, and also for fixing thin plate of simple construction. It cannot be used for metal-to-metal bonding and fixing.
1. Heart hardness: standard value HRC28-38. The test is carried out on a section 1-2 times the nominal diameter from the tail. If the nominal length is too short, it can be embedded first, and then the hardness is measured.
2. Surface hardness: standard MINHV450.
3. Carburized layer: standard 4#-6#: 0.05-0.18mm, 8#-12#: 0.10-0.23mm, 14#: 0.13-0.28mm. The main purpose of carburization is to increase the surface hardness and ensure the strength of the teeth. If the decarburization is too deep and the carburization is insufficient, the strength of the teeth will not meet the requirements, that is, the teeth will be damaged during the screwing test.
4. Torque: standard specification 4#5#6#7#8#10#12#14#A tooth 14212835455696145AB tooth 142128354565102165.
