Study on geometrical and dimensional changes in isothermal precision forging with complex shape during air cooling process

Abstract

A series of experiments were made to analyse geometrical and dimensional changes of an aluminium alloy ring seat during the air cooling process. Geometrical and dimensional changes were measured by a structured light scanner. The corresponding microstructure evolution of 7A09 aluminium alloy was characterised using thermal simulating experiment, X‐ray diffraction and transmission electron microscopy. Experimental results indicate that geometrical and dimensional changes are closely correlated with the shape of isothermal precision forging during the air cooling process. The main reasons for distortions are non‐uniform thermal field in the workpiece and inhomogeneity of the coefficient of thermal expansion caused by the microstructure evolution.

Keywords:

• Isothermal precision forging
• Air cooling process
• Geometrical and dimensional change

The authors thank National Natural Science Foundation of China (grant no. 50775051) and Youth Technology Speciality Fund of Harbin (grant no. 2008RFQXG052) for their financial support. The authors also thank Postdoctoral Researcher Y. Zhao and Dr M. H. Wang of the Superplasticity and Plasticity Institute of Jilin University for the performing of the structured light measurement, and Professor Y. Q. Song, academician of Chinese academy of sciences for his great support to this research.