Innovation in producing crane rail fishplate using Fe–Mn–Si–Cr based shape memory alloy

Abstract

An Fe–Mn–Si–Cr shape memory alloy is applied to make crane rail fishplates. The shape recovery of the reverse martensite transformation from hcp to fcc is utilised to connect finite lengths of rail. Rails connected by normal steel fishplates gradually become separated at the joint and can be damaged by broken flakes in the gap and dents during heavy duty operation of the crane. To eliminate such problems, a sufficient and controlled compressive stress is required at the joint to resist the stress responsible for creating the gap. A quantitative estimate of the load required to separate the joint has been made to calibrate the compressive stress yielded by the reverse martensite transformation of fishplates. An innovative joining technique that ensures adequate and controlled compressive stress at the joined parts has been developed using a Fe–Mn–Si–Cr shape memory alloy together with sophisticated materials design and installation techniques.