Effect of Lubrication Conditions on the Forming Limit of Deep Drawing of 6061 Aluminum Alloy Sheet

2019 ◽  
Vol 944 ◽  
pp. 85-91
Author(s):  
Yan Qi Wang ◽  
Yong Qi Cheng ◽  
Peng Zhang ◽  
Gan Luo ◽  
Peng Bin Li ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Sheet Metal Forming ◽  
Deep Drawing ◽  
Metal Forming ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Oil Lubrication ◽  
Aluminum Alloy Sheet ◽  
Ptfe Film ◽  
6061 Aluminum Alloy

With the development of lightweight vehicles, aluminum alloy sheets are increasingly used in the automotive field. However, the aluminum alloy sheet has poor forming performance at room temperature. Therefore, how to improve the sheet metal forming performance of aluminum alloy sheet has become one of the current research hotspots. In this paper, the effects of different lubricants on the deep drawing forming properties of 6061 aluminum alloy sheets were studied by cupping experiments. The effects of lubricants on the deep drawing of sheet metal forming and the wall thickness of cups after deep drawing were explored. The results show that under the condition of drawing speed of 3MPa and 200mm/min, the ultimate drawing ratio of the sheet under oil lubrication is 1.92, and the PTFE film is 2.16. Grease and graphite lubrication are respectively 2.12 and 2.03, using PTFE film lubrication can increase by about 10% contrast with the oil lubrication. The measurement of the wall thickness of the cup under the forming limit state shows that the position with the largest reduction rate appears in the rounded transition zone, and the wall portion of the cylindrical member increases with the height of the wall, and the thickness from the bottom of the cup to the bottom of the cup. The edges all show a trend of decreasing first and then increasing.

scholarly journals Forming Limit Research of 5182 Aluminum Alloy Sheet Based on Lou-2013 Ductile Fracture Criterion

2019 ◽  
Vol 55 (16) ◽  
pp. 47 ◽  
Author(s):  
YANG Zhuoyun ◽  
ZHAO Changcai ◽  
DONG Guojiang ◽  
CHEN Guang ◽  
ZHU Liangjin ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Ductile Fracture ◽  
Fracture Criterion ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Aluminum Alloy Sheet ◽  
Ductile Fracture Criterion

scholarly journals Aluminum Alloy Sheet-Forming Limit Curve Prediction Based on Original Measured Stress–Strain Data and Its Application in Stretch-Forming Process

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1129 ◽  
Author(s):  
Lirong Sun ◽  
Zhongyi Cai ◽  
Dongye He ◽  
Li Li
Keyword(s):  
Aluminum Alloy ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Aluminum Alloy Sheet ◽  
Limit Curve ◽  
Forming Process ◽  
Forming Limit Curve ◽  
Stress Strain ◽  
Strain Relation ◽  
Stress Strain Relation

A new method, by directly utilizing original measured data (OMD) of the stress–strain relation in the Marciniak–Kuczynski (M–K) model, was proposed to predict the forming limit curve (FLC) of an aluminum alloy sheet. In the groove zone of the M–K model, by establishing the relations of the equivalent strain increment, the ratio of shear stress to the first principle stress and the ratio of the second principle stress to the first principle stress, the iterative formula was established and solved. The equations of theoretical forming limits were derived in detail by using the OMD of the stress–strain relation. The stretching specimens of aluminum alloy 6016-T4 were tested and the true stress–strain curve of the material was obtained. Based on the numerical simulations of punch-stretch tests, the optimized specimens’ shape and test scheme were determined, and the tests for FLC were carried out. The FLC predicted by the proposed method was more consistent with the experimental results of FLC by comparing the theoretical FLCs based on OMD of the stress–strain relation and of that based on traditional power function. In addition, the influences of anisotropic parameter and groove angle on FLCs were analyzed. Finally, the FLC calculated by the proposed method was applied to analyze sheet formability in the stretch-forming process, and the predicted results of FLC were verified by numerical simulations and experiments. The fracture tendency of the formed parts can be visualized in the forming limit diagram (FLD), which has certain guiding significance for fracture judgment in the sheet-forming process.

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