Fatigue failure of steel links operating as chain components in a heavy duty draw bench

Steel links used as chain elements in draw benches are subjected to repetitive tensile stressing due to successive loading and un-loading conditions. In addition, friction caused by poor or improper lubrication can be very harmful, due to associated surface degradation and wear/corrosion related processes which play an important role to the integrity and performance of the machine components. Frequent in-service failures of chain links occurred in a copper tube draw bench have led to increased maintenance costs and machine downtime resulting in poor productivity indicators. Samples from fractured components, made of induction hardened structural steel, were brought for a failure analysis investigation. Failure analysis findings suggest strongly that the failure was accomplished by the operation of fatigue mechanism initiated at the inner-eye area of the link and followed by brittle overload fracture. Review of the service history (operating conditions, applied loads), in combination to the examination of a potential substitution of the material to a more fatigue resistant one are recommended as further fatigue damage preventive actions.