Cause Analysis on Cracks of Adjusting Nuts

Cracks were found inside the adjusting nuts when testing after quenching and tempering treatment, and by means of macroscopic examination, chemical compositions analysis and metallographic examination, the cracking reason was analyzed. The results show that the cracks of the adjusting nuts were quenching cracks which were caused by the obvious banded segregation and more inclusions in microstructure of the adjusting nuts. At the same time, the tempering temperature is too high, and reticular ferrite appeared on both sides of the cracks because of decarburization.