鋁合金輪圈鍛造成形性與晶粒演化分析

• Main Authors: Li, Mingchiou, 李銘秋
• Other Authors: Aoh, Jongning
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/25524745957192103308

碩士 === 國立中正大學 === 機械工程學系暨研究所 === 100 === The objective of aluminum alloy forging is to fabricate mechanical components of complicated geometry by direct hot forming of a billet to a near net shape so that less subsequent machining is required. In forging process the key factors are optimal mold design and process parameters. The mold design is also related to the number of passes required during forging process, which has significant influence on the precision of forging, forging defects and mold life. Therefore it is essential to analyze the plastic flow behavior of the billet to predict the possible inhomogeneous deformation, flow separation and dead zone occurred in the workpiece. CAE software is an indispensable tool to integrate and to apply on forging process and mold design to predict the forging results. In this study, up-set forging experiment was conducted on Gleeble tester to acquire Al6061 flow curves as material data base for numerical simulation analysis using SIMUFACT software to simulate the forging process of aluminum alloy wheels. The flow behavior, strain distribution, temperature profile, forging streamline, stagnation and separation phenomenon, during forging of aluminum wheels were explored and compared with those obtained from real forging. The accuracy of the numerical simulation was verified. Detailed metallographic investigation was conducted on the wheel cross section to reveal the material flow pattern and the grain distribution, A grain type distribution map was established. Further modification of the mold was conducted to improve the billet flow during forging process. An optimal material flow enabled uniform strain distribution and more densed streamlines. It also reduced stagnation and separation so that the cracks or defects ca n be reduced or eliminated. In addition, grain size distribution and recrystallization phenomenon were analyzed on the specimen cross-section after Gleeble upset forging experiment. Grain size information obtained from Gleeble test was compared with actual forged piece under same strain, strain rate and temperature conditions. A strain, strain rate, temperature and grain distribution map can be established for the aluminum wheel forging process.