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Products & Technology

Fatigue Resistant Steel Plates AFD™

Thin fatigue-resistant plate for steel structures, contributing to improved bridge safety

To improve the safety of bridges, JFE’s thin anti-fatigue damage steels (AFD steels) for steel structures reduces the fatigue crack propagation rate to 1/2 of the rate of ordinary steel plates.
Microstructure control of the steel is applied to the increase of branching and bending of fatigue cracks, suppressing the stress intensity factor (△K) at fatigue crack tip.
The fatigue resistance of members can be improved by applying AFD steels to members that are particularly susceptible to fatigue crack initiation.

Mechanism of suppression of fatigue crack propagation rate

Dispersion of hard phases in steel microstructure increases bending and branching of fatigue cracks.

Bending and branching of fatigue cracks are increased by microstructure control to disperse fine hard phases.


Distribution of fatigue crack propagation rate

In AFD steel, the fatigue crack propagation rate is reduced to 1/2 or less than the upper limit of ordinary steels by reducing the range of the stress intensity factor (K) around the crack tips.