Expansion bolts are commonly used anchoring fasteners. They achieve fixation by expanding the sleeve against the hole wall to generate friction, suitable for anchoring in concrete, masonry and similar substrates. Their specifications shall be determined according to specific application requirements, mainly including bolt diameter, effective length and expansion sleeve dimensions.
Expansion bolt specifications are usually designated by bolt thread diameter. Common sizes include M6, M8, M10, M12, etc., where "M" denotes metric thread and the following number represents the nominal bolt diameter in millimeters.
The length of an expansion bolt is determined by connection requirements, generally based on the thickness of the fastened component, the embedment depth in the substrate and the sleeve length, measured in millimeters.
The expansion sleeve dimension is an important part of the specification, determined by matching the drilled hole diameter with the bolt diameter. It is usually expressed by outer diameter and inner diameter in millimeters.
It should be noted that specific specifications shall be determined according to actual working conditions and design requirements. For selection, professional advice may be sought or relevant standards and specifications referenced.
The following factors should also be considered when selecting expansion bolts:
Material: Expansion bolts are usually made of carbon steel (electro-galvanized or hot-dip galvanized) or stainless steel. The appropriate material shall be chosen according to corrosion resistance and strength requirements of the service environment.
Load capacity: This refers to the maximum pull-out and shear loads the bolt can withstand, depending on bolt diameter, embedment depth, sleeve type, substrate strength and material strength.
Installation conditions: Expansion bolts are installed after drilling into the substrate. The hole diameter, hole depth and hole cleaning quality affect anchoring performance and shall match the sleeve specification.
Installation tools: A matching wrench or power tool is required for installation, and tools suited to the bolt size and type shall be selected to ensure proper tightening.
It should be emphasized that for specific projects and applications, it is recommended to consult professional engineers or refer to relevant standards and specifications to determine suitable expansion bolt specifications, so as to ensure the reliability and safety of the anchoring connection.
