Quenched Residual Stress Reduction in Pentagon-Curved Aluminum Alloy Forgings Using the Bulging Process

Area of Science:

• Materials Science
• Mechanical Engineering
• Manufacturing Processes

Background:

• Quenched residual stress in pentagon-curved forgings (PCGs) causes significant machining deformation.
• Geometric characteristics like edge distance ratio (e/D) influence stress levels.

Purpose of the Study:

• To mitigate quenched residual stress in PCGs using the bulging method.
• To investigate the relationship between edge distance ratio (e/D) and stress reduction.
• To determine the optimal bulging ratio for stress alleviation.

Main Methods:

• Development of a thermo-mechanical model incorporating quenched residual stress and e/D.
• Creation of a bulging finite element (FE) model to simulate stress reduction.
• Experimental validation using X-ray diffraction and the contour method.

Main Results:

• Increasing e/D amplifies internal and surface stresses.
• Stress reduction is inversely proportional to e/D; lower e/D yields greater reduction.
• A 2% bulging ratio demonstrated the most significant overall stress reduction.

Conclusions:

• The bulging method effectively alleviates quenched residual stress in PCGs.
• FE model predictions align with experimental measurements, confirming model accuracy.
• Optimizing e/D and utilizing a 2% bulging ratio are key for stress mitigation in PCGs.