• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.521-526
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• 2017

In the GTA welding process of Al 7075 alloy using different types of filler metals, the tensile test and micro-hardness test were conducted to evaluate the mechanical characteristics. Also, the radiographic test result showed that the weld met the criterion of level 1 in accordance with KS D 0242 for verifying the welding integrity and there were no welding defects. The tensile test result obtained using Al 7075 as a filler metal showed that the material was fractured in the weld zone. The tensile strengths of the materials using Al 7075 and ER 4043 as the filler metal were about 240MPa and 253MPa, their yield strengths were about 132MPa and 120MPa and their elongation percentages were 6.6% and 13%, respectively. The micro-hardness value of the deposited metal zone when using Al 7075 as the filler metal was Hv 132. However, the micro-hardness of the material using ER4043 as the filler metal was about 24% lower than that using Al 7075. When the chemical composition of the filler metal is the same as that of the material itself, fracture can occur in the deposited metal zone. Therefore, it is not desirable to use the same material as the filler metal for the welding of Al 7075 alloy. Moreover, the use of Al-Si based ER 4043 as a filler metal is more desirable than using the same material as a filler metal for welding Al 7075.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.4
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• pp.73-79
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• 2003

The tensile strength test and the analysis for the section of brazing were performed in the cases of materials used for combustion chamber of regeneratively cooled liquid rocket engine. BNi-2 and BNi-7 based on nickel were used for brazing as filler metal. The properties of material and filler metal were analyzed by tensile strength test and metal microscope for 12 specimens. The tensile-strength of brazing for chrome-copper alloy and other kinds of alloy was higher than that of chrome-zirconium-copper alloy and other kinds of alloy The tensile strength in the case of BNi-2 as filler metal was higher than that of BNi-7 because the wetting property of BNi-2 was better than that of BNi-7.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.113-119
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• 2006

Brazing is an important manufacturing process in the fabrication of Heavy Water Reactor fuel rods, in which bearing and spacer pads are joined to Zircaloy-4 cladding tubes. The physical vapor deposition(PVD) technique is currently used to deposit metallic Be on the surfaces of pads as a filler metal. Amorphous Zr-Be binary alloys which are manufactured by rapid solidification process are under developing to substitute the conventional PVD-Be coating. In the present study, brazed joint with PVD and amorphous alloys of $Zr_{1-x}Be_{x}(0.3{\le}x{\le}0.5)$ as filler metals are compared by mechanism, microstructure and hardness. The thickness of brazed joint with amorphous alloys became much smaller than that of PVD-Be. The erosion of base metal did not occur in the brazed joint with amorphous alloys. The brazing mechanism for PVD-Be seems to be Be diffusion into Zr-4 with capillary action resulting from eutectic reaction while that for amorphous alloys are associated with the liquid phase formation in the brazed joint. The brazed joint microstructure with PVD-Be consists of dendrite while that with amorphous alloys is globular. The $Zr_{0.7}Be_{0.3}$ alloy shows the smooth interface with little erosion in the base metal and is recommended a most suitable brazing filler metal for Zircaloy-4.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.98-100
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• 2003

• Proceedings of the KWS Conference
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• 1990.04a
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• pp.103-106
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• 1990

• Proceedings of the KWS Conference
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• 1994.05a
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• pp.103-105
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• 1994

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.231-233
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• 2003

• The Science & Technology
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• v.25 no.2 s.273
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• pp.76-79
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• 1992

• Proceedings of the KWS Conference
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• 1994.05a
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• pp.109-112
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• 1994

• Proceedings of the KWS Conference
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• 1999.05a
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• pp.96-97
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• 1999