순티타늄판의 Nd:YAG 레이저 용접성에 관한 연구(Ⅱ) - 맞대기 용접 특성 - (A Study of Weldability for Pure Titanium by Nd:YAG Laser (Ⅱ) - Welding Properties of Butt Welding -)

서지정보

· 발행기관 : 대한용접접합학회
· 수록지 정보 : 대한용접접합학회지 / 27권 / 6호 / 68 ~ 73페이지
· 저자명 : 김종도, 송무근, 박성하, 곽명섭, 박성하

초록

Recently, as titanium and titanium alloys are being increasingly used in wide areas, there are on-going
researches to obtain high quality weld zone. In particular, growing interest is being drawn to laser welding,
which involves low heat input and large aspect ratio in various welding processes and can facilitate shield
in atmospheric condition compared with electron beam welding.
The first report covered the analysis of embrittlement by the bead color of weld zone through
quantitative analysis of oxygen and nitrogen and measurement of hardness as basic experiment to apply
laser welding to titanium. Results indicated that the element that affect embrittlement the most was
nitrogen, and as embrittlement and oxygenation go on, bead color changed to silver, gold, brown, blue and
gray.
This study performed butt welding of pure titanium and STS304 by using 1kW CW Nd:YAG laser, and
to find out basic physical properties, evaluated welding performance by laser output, welding speed, root
gap and misalignment etc, and examined mechanical properties through tensile stress and Erichsen test. The
reason particles of pure titanium welded metal and HAZ are greater than STS304 is because they are pure
metal and do not include many impure elements that work as nuclei in case of resolidification, thus
becoming coarse columnar crystals eventually. In addition, the reason STS304 requires more energy during
welding than pure titanium is because the particle size of base metal is smaller.

영어초록

Recently, as titanium and titanium alloys are being increasingly used in wide areas, there are on-going
researches to obtain high quality weld zone. In particular, growing interest is being drawn to laser welding,
which involves low heat input and large aspect ratio in various welding processes and can facilitate shield
in atmospheric condition compared with electron beam welding.
The first report covered the analysis of embrittlement by the bead color of weld zone through
quantitative analysis of oxygen and nitrogen and measurement of hardness as basic experiment to apply
laser welding to titanium. Results indicated that the element that affect embrittlement the most was
nitrogen, and as embrittlement and oxygenation go on, bead color changed to silver, gold, brown, blue and
gray.
This study performed butt welding of pure titanium and STS304 by using 1kW CW Nd:YAG laser, and
to find out basic physical properties, evaluated welding performance by laser output, welding speed, root
gap and misalignment etc, and examined mechanical properties through tensile stress and Erichsen test. The
reason particles of pure titanium welded metal and HAZ are greater than STS304 is because they are pure
metal and do not include many impure elements that work as nuclei in case of resolidification, thus
becoming coarse columnar crystals eventually. In addition, the reason STS304 requires more energy during
welding than pure titanium is because the particle size of base metal is smaller.

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