Analysis on Cracking Cause of 7A04 Forging Nut

By means of chemical composition analysis, hardness testing, macro and micro examination, the cause of cracking in the thread roots of a nut was analyzed. The results showed that the cracking was due to the design flaw of nut, the undercut was designed for the parting surface of die forgings, resulting in non-forging organizations in the key parts of thread roots, and the strength was weakened.