Briefly describe the key points for quality inspection of building fasteners before use
The quality inspection of building fasteners before use is a key link to ensure the safety of scaffolding, and the following points need to be focused on:
VISUAL INSPECTION
Check if there are cracks or deformations in the fasteners (such as bent cover plates or concave bases), and if there are burrs or flying edges at the edges; Whether the bolts and nuts are complete, whether the threads are worn or loose, and whether the washers are fully matched. If there are cracks or severe deformations, it is directly judged as unqualified.
Size and fit
Measure the diameter of the fastener clip with a caliper, which should match the outer diameter of the matching steel pipe (usually 48.3mm). If the gap is too large (>1mm), it will affect the clamping force; Check the opening angle of the fastener. The contact surface between the two upright poles of the right angle fastener should be perpendicular, and the rotating fastener should rotate flexibly without any jamming.
Material and Identification
Check the product certificate and confirm that the material is malleable cast iron (KT33-8) or cast steel, avoiding the use of inferior materials such as gray cast iron; Check for manufacturer identification, production date, and batch. Fasteners without identification or from unknown sources are prohibited from use.
Performance sampling inspection
Randomly select samples for simple testing: when the bolt is tightened to 40-65N · m, check whether it can withstand normal force and whether there are any slipping buckles; The shear resistance of the docking fastener can be tested by manual shaking, and if there is obvious looseness, it is unqualified.
Rust and wear inspection
Fasteners with surface rust area exceeding 1/3 or bolt rust that prevents normal tightening require rust removal and repair before retesting. Those with severe rust should be scrapped directly.
Through the above inspection, unqualified fasteners can be removed to ensure that they meet the safety requirements for load-bearing and connection during use.
