A Study on Micro Tig Tube Welding of Thin Extra Aisi 321 Austenitic Stainless Steel Sheets

Yıl 2018, Sayı: 4, 263 - 270, 04.12.2018

Mehtap Hıdıroglu Orhan Serce Huseyin Karabulut Yusuf Ayan Nizamettin Kahraman

Öz

Exhaust
gas recirculation tubes were used for this study. To make bellows shape from
TIG (Tungsten Inert Gas) welded extra thin tubes hydraulic forming method is
used in industry. For this study, 0.2 mm thick AISI 321 austenitic sheets were
combined by using micro TIG welding method and 11.80 mm in diameter pipes were
produced. For the TIG welding process of thin sheet tubes shaped by liquid
pressure precise welding parameter adjustment is required. With the micro TIG
arc welding technique, healthy weld seams were obtained in three different
power parameters. The effects of this differences on the mechanical properties
and microstructure of the weld joints were experimentally investigated. The
welding speed was kept constant and three different welding current and voltage
values were selected. The images of the weld zone of the samples were taken by
an optical microscope. The microstructures formed in the weld zone were
examined. Micro hardness values of the base metal, HAZ (Heat Affected Zone) and
weld zone were evaluated. Tensile tests of the samples were carried out for
three different parameters. Strength of welding seams is very important in the
hydroforming process. In order to evaluate the strength of the joint, the
welded tube elastomer expansion test was applied. The effect of the expanding
tube wall on the welded joint was evaluated by the expansion test. As a
consequence of the study, the optimum power parameters of the welded joint was
determined by destructive and non-destructive tests.

Anahtar Kelimeler

TIG welding, EGR tubes, Elastomer expansion test

Kaynakça

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