Analysis on Fracture Reasons of Sleeve Limbs of Hollo-Bolt One-Way Bolts

Imported Hollo-Bolt one-way bolts were prone to shearing failure on position of the sleeve limbs during the prefabricated assembly construction. By means of chemical composition analysis, hardness testing, metallographic inspection, scanning electron microscopy observation and neutral salt spray test for the failure Hollo-Bolts, the reasons for failure during bearing test were analyzed. The results show that:the material of slotted sleeves of Hollo-Bolts was relatively soft and lack of reasonable heat treatment process, and the effect of galvanized anti-rust surface treatment was not ideal; as a result of it, the strength of the sleeves reduced, which led to the shear failure of sleeve limbs. Finally,the optimization proposals were put forward according to the reasons.