Some of them are manifested in the appearance of forgings, such as external cracks, folds, wrinkles, lack or loss of meat, pits, rough surface or orange peel.

2. Some of them are manifested in forgings, such as various macro-structural defects, such as cracks, hairlines, pores, coarse grains, surface decarburization, nonmetallic inclusions and heterogeneous metal inclusions, white spots, segregation, dendrites, residual shrinkage, disordered streamline, non-ferrous metal flow, coarse grain rings, oxide films, etc.

3. Some of them are reflected in the microstructure, such as the precipitation of the second phase;

4. Some quality problems of crane wheel forgings are reflected in forging performance, such as unqualified room temperature strength or plasticity, toughness and fatigue performance, unqualified high temperature performance or cold and hot fatigue performance such as instantaneous strength, persistent strength, persistent plasticity and creep strength;

5. Whether it is manifested in the external parts of crane wheel forgings or in the internal parts and performance quality problems of crane wheel forgings, in most cases, they are interactive, often interrelated, accompanied and vicious circle. For example, overheating or overburning usually causes defects such as coarse grains, forging cracks, decarburization of the surface and reduction of mechanical properties such as plasticity and toughness; Inclusions in materials may cause internal cracks, and the further expansion and development of internal cracks may be exposed as surface cracks of forgings.