Abstract: The creep fracture and thermal fatigue cracking failure of Ni saving low-cost heat-resistant cast steel grate plate for pellet production were studied by observing the fracture morphology, microstructure and mechanical properties. The results show that the transformation of δ→γ+σ occurs during the service process, the proportion of ferrite decreases from 65% to 10%, the proportion of austenite increases from 30% to 85%. The σ harmful phase results in a significant reduction in the yield strength of 106.3 MPa, resulting in grate failure.