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Studies on the Friction Stir Welding of Aluminum Alloy Sheets by Using High Speed Steel Tool Inserted Aluminum Alloy

In this study, a novel inserted type of friction welding tool was
proposed, where the circular rod was embedded in its central axis using the
material same as the workpiece, so that it could effectively promote the
friction heat quickly and enhance the welding quality. The welding tool
was made of the high-speed steel, the workpiece with its embedded
material 6061-T6 aluminum alloy. A vertical milling machine equipped
with dynamometer, which could measure the power during the friction stir
welding, was employed as the experimental apparatus. During the welding
process, the K-type thermocouple was used simultaneously in measuring
the welding temperature at the interface of joint. The operating conditions
of welding were as followings: the welding speed of 800 rpm, the tool
inclination of 1¢X and the clamping force 2kN, the tool with 12mm in
diameter and 0.21mm in depth under the downward force about 2 kN. The
experiment was conducted into two stages.
The first stage was a spot welding to investigate the effect of the ratio
of the diameter of embedded material (d) to the diameter of welding tool (D)
on the temperature of the interface of joint, the thickness of plastic flow,
and the failure load of weld. Experimental results revealed that the interface
temperature, the plastic flow thickness, and the failure load of weld are
directly proportional to d/D. In comparison with the welding tool without
insert (d/D = 0), the maximum interface temperature increased about 1.12
times at d/D = 0.83, the plastic flow thickness increased about 1.52 times,
and the failure load of weld increased about 1.45 times. In the second stage,
the feeding process was included to investigate the influence of the
diameter and the thickness of embedded material on the interface
temperature, the plastic flow thickness, and the failure load of weld.
Experimental results revealed that the plastic flow thickness was less than 2
mm when the thickness of embedded material was less than 3 mm.
However, when the thickness of embedded material was larger than 5 mm,
the plastic flow thickness could achieve to 3 mm. Hence, the thickness of
embedded material should be larger than 5mm. Moreover, the effect of the
diameter of embedded material on the interface temperature and the plastic
flow thickness using the feeding process was almost the same as the spot
welding. However, in comparison with the welding tool without insert, the
failure load of weld increased about two times.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0819111-100631
Date19 August 2011
CreatorsSu, Fang-Hua
ContributorsYeau-Ren Jeng, Yuang-Cherng Chiou, Jen Fin Lin, Rong-Tsong Lee
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0819111-100631
Rightsuser_define, Copyright information available at source archive

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