The Effect of In Situ Forging Process Parameters During Casting on Segregation Types and Mechanical Properties of Al–Cu Alloy Steering Knuckles
摘要
This study employs an in situ forging process during casting to produce Al–Cu alloy steering knuckles. The components underwent X-ray inspection, macroscopic section observation, and metallographic analysis. The results demonstrated that the forging process can effectively improve the quality of squeeze-cast steering knuckles and mitigate internal defects. Under the “pulldown + forging” process conditions, the tensile strength of the alloy reached above 410 MPa when the casting and forging interval was 5 s, 6 s, or 7 s, followed by an elongation of 4%. However, the mechanical properties of the alloy deteriorated when the casting and forging interval time was extended to 8 s and 9 s, with the tensile strength decreasing to 380 MPa and the elongation only reaching 1%. Additionally, the main types of alloy segregation were cloud-like segregation and linear segregation when the casting and forging interval was 5 s, 6 s, and 7 s. Regarding the alloy with a casting and forging interval of 8 s and 9 s, the main type of segregation was block segregation. As the interval between casting and forging increases, the time the alloy spends in the mushy zone before forging becomes longer, leading to the formation of block segregation after forging and a decline in the mechanical properties of the alloy.