Carriage bolts, also known as round head square neck screws, carriage
bolts are divided into large half round head carriage bolts
(corresponding to standard GB/T14 and DIN603) and small half
round head carriage bolts (corresponding to standard GB/T12-85)
according to the size of the head. Carriage bolt, a type of fastener
consisting of two parts, head and screw (cylinder with external thread),
used in conjunction with a nut to fasten two parts with through holes.
The carriage bolt is applied in the slot, the square neck is stuck in the slot
during the installation process, which can prevent the bolt from rotating,
and the carriage bolt can move parallel in the slot. Because the head of
the carriage bolt is round, there is no design of available assisting tools
such as a cross slot or hex, and it can also play a role in preventing theft
during the actual connection process.
The mechanical performance requirements of carriage bolts are divided
into 8.8, 10.9 and 12.9 grades. Class 8.8 indicates that the minimum
tensile strength is 800MPa and the minimum yield strength is 640MPa.
Class 10.9 indicates a minimum tensile strength of 1000MPa and a
minimum yield strength of 900MPa; Class 12.9 indicates a minimum
tensile strength of 1200MPa and a minimum yield strength of 1080MPa.
Because the fasteners with black zinc plating have good corrosion resistance and wear resistance, they are suitable for harsh working environments, such as Marine environments and chemical equipment.In addition, black zinc plated fasteners are also commonly used in occasions requiring higher aesthetics, such as automotive, electronics and other industries.
