Abstract: After the opening of the 0Cr17Ni4Cu4Nb steel electroslag ingot, cracks were found at the corners of the billet. The cause of the billet cracks was analyzed by means of macroscopic observation, chemical composition analysis and metallographic examination. The results show that the content of carbon, nitrogen, nickel and other elements in the cracked steel billet was relatively low, resulting in a higher ferrite content and a wider ferrite band width in the material. The poor plasticity of the ferrite enrichment zone ultimately led to cracking of the steel billet. Increasing the content of elements such as carbon, nitrogen and nickel in steel billets could improve the surface quality of the billets and avoid the occurrence of cracks.