When using the screw, if you can understand the mechani […]
When using the screw, if you can understand the mechanical properties of the screw first, then you can use the screw better. Different types of screws have different mechanical properties and different mechanical properties, which leads to different situations in which the screws are used.
First, self-tapping screws: mechanical performance requirements
1. Heart hardness: standard value HRC28-38. When testing, take a section from the tail 1-2 times the calling diameter. If the length is too short, you can first embed it and then measure the hardness.
2. Surface hardness: standard MIN HV450.
3. Carburized layer: standard 4#-6#: 0.05-0.18mm, 8#-12#: 0.10-0.23 mm, 14#: 0.13-0.28 mm. The main purpose of carburizing is to enhance the surface hardness and ensure the strength of the teeth. If the decarburization is too deep, the carburization is insufficient, and the strength of the teeth will not be required. That is, the teeth are damaged when the screwing test is performed.
4. Torque: Standard specification 4#5#6#7#8#10#12#14#A tooth 14212835455696145AB tooth 142128354565102165165.
5. Screw-in test: Screw the self-tapping screw into a steel plate with a reserved test hole. The self-tapping screw should form a matching thread in the test plate, and the thread of the screw itself will not be deformed and damaged until the end The taper thread is completely over the test plate. The screw-in test is only applicable to self-tapping screws of type AB, B, BP, etc. The IFI stipulates that the test plate is prepared by using semi-hard low-carbon cold-rolled steel with a hardness of 70–85 HRB. The standard specifications of the steel plate, ie the thickness, are shown in the table below. The test hole should be punched or drilled. The tolerance is the specified nominal diameter (see table below) ± 0.025 mm. 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.
Second, wallboard nails
1. Heart hardness: Standard: HRC24-45.
2. Surface hardness: Standard: HV600-800.
3. Carburized layer: 4#-6# 0.05-0.18mm, 8#-12#0.10-0.23, 14# 0.13-0.28.
4, bending: the requirement is 150 - 450
5, salt spray test: generally MIN 48h.
6. Torque: Specification 6#7#8#10# Torque 21283558.
Third, the tail screw
1. Core hardness: Standard: HRC32-40 The company's products are measured as HRC31.7-39.0.
2, surface hardness: standard: HV600-700 The company's products are measured around HV620.
3. Hard layer: 4#-6# :0.05-0.18mm 8#-12#:0.10-0.23mm 14#:0.15-0.28mm
4. Torque: specification, drill tail, screw, TYPE BSDTYPE CSDINCH-LBKG-CMINCH-LBKG-CM4#(2.9)141614166#(3.5)242824288#(4.2)4248485510#(4.8)6170657512#(5.5)9210610011514#(6.3 ) 150173156180.