Centerline Cracking in Forged Cu-30Ni-0.5Fe Bars

A failure analysis was conducted on Cu30-Ni0.5-Fe forgings, which experienced severe centerline cracking during open die forging operations, exhibiting a failure rate of approximately 15%. The alloy is well understood to have excellent workability at all temperatures. The initial root cause of the cracking was determined to be void evolution resulting from interdendritic porosity present in the input material, which was subsequently exaggerated by forging practices. To remedy the failures, a modified thermomechanical process (TMP) was implemented. Later statistical analysis of the resultant forgings showed little improvement to forgeability using the new TMP. Thus, further analysis was conducted. The raw material was scrutinized, and the effects of alloying elements and apparent porosity on hot workability were assessed.