Lightning hexagonal drill tail with pad self tapping galvanized dovetail screw color steel tile nail drill tail nail six Corner drill tail screw

If you can first understand the mechanical properties of screws when using them, then you can better use them. Different types of screws have different mechanical properties, and the different mechanical properties result in different occasions in which screws are used. 1、 Self tapping screws: Mechanical performance requirements 1. Core hardness: standard value HRC28-38. When testing, take 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 can be measured. 2. Surface hardness: Standard MIN HV450. 3. Carbonized 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 enhance surface hardness and ensure the strength of teeth. If the decarburization is too deep and the carburization is insufficient, the strength of the teeth will not meet the requirements, which means that the teeth will be damaged during the screw in test. 4. Torque: Standard specifications 4 # 5 # 6 # 7 # 8 # 10 # 12 # 14 # A teeth 14212835455696145AB teeth 142128354565102165. 5. Screw in test: Screw the self tapping screw into a steel plate with reserved test holes. The self tapping screw should form a matching thread in the test plate, and the thread of the screw itself should not deform or be damaged until the end taper thread completely passes through the test plate. The screw in test is only applicable to self tapping screws of types AB, B, BP, etc. According to IFI regulations, the test plate should be prepared from semi hard low-carbon cold-rolled steel with a Rockwell hardness of 70-85HRB. The standard specifications for steel plates, including thickness, are shown in the table below. The test holes should be punched or drilled, with a tolerance of ± 0.025mm for the specified nominal diameter (see table below). Specification 6 # 7 # 8 # 10 # 12 # 1/4 test plate thickness (mm) 1.85-1.953.12-3.234.68-4.84 aperture (mm) ± 0.0252.953.263.454.044.765.50.