Failure of Chain Anchor Pins on a Fork Lift Truck

Abstract

This paper documents investigation of the cause of failure of chain anchor pins on a fork lift truck, including recommendations to prevent reoccurrence. The pins failed from hydrogen embrittlement caused by atomic hydrogen being produced as corrosion occurred in the crevice region of the anchor pin. High strength materials such as that used for this pin are susceptible to this type of failure mechanism. To prevent this type of damage, the chains and anchor pins need to be on a regular maintenance, lubrication, and replacement program. The objective is to keep the equipment clean and lubricated to prevent corrosion and minimize wear, in accordance with advice given by BITA, the British Industrial Truck Association and other manufacturers of truck lifts.