Low-cycle fatigue behavior for stainless-clad 304+Q235B bimetallic steel

Stainless-clad bimetallic steel is a high-performance steel with the advantages of cost and mechanical resilience. As the low-cycle fatigue characteristics of a material is essential for the seismic performance of structures, this paper investigates the low-cycle fatigue properties of a stainless-clad 304 + Q235B bimetallic steel plate through a series of strain-controlled fatigue tests to gain a comprehensive understanding of the cyclic response, failure mode and fatigue strength of this material. Fatigue test results indicate that most of the fatigue cracks initiate and propagate in the side of substrate layer Q235B carbon steel, and no interface debonding is found till the fracture occurrence of the test coupons. The different applied strain ratios have negligible effects on the fatigue life of the 304 + Q235B bimetallic steel due to the effect of the mean stress relaxation. The level of the observed cyclic hardening shows positively related with the cycled strain amplitude. Comparison of the Coffin-Manson strain-life curves between different steel grades further proves this 304 + Q235B bimetallic steel possesses excellent low cycle fatigue resistance. Finally, the calibration and verification of the nonlinear isotropic/kinematic hardening model parameters for this bimetallic steel are conducted and provide a good description of the experimental results.