순티타늄판의 Nd:YAG 레이저 용접성에 관한 연구(Ⅲ) - 에지 용접 특성 - (A Study of Weldability for Pure Titanium by Nd:YAG Laser (Ⅲ) - Weld Properties of Edge Welding -)

서지정보

· 발행기관 : 대한용접접합학회
· 수록지 정보 : 대한용접접합학회지 / 27권 / 6호 / 74 ~ 79페이지
· 저자명 : 김종도, 길병래, 송무근, 곽명섭

초록

Titanium and titanium alloy can be reproduced immediately even if oxide films(TiO2) break apart in sea
water. Therefore, since titanium demonstrates large specific strength and outstanding resistance to stress
corrosion cracking, crevice corrosion, pitting and microbiologically influenced corrosion in sea water environment,
it has been widely applied to heat exchanger for ships. In particular, with excellent elongation, pure
titanium may be deemed as optimal material for production of heat exchanger plate which is used with
wrinkles formed for efficient heat exchange.
Conventional plate type heat exchanger prevented leakage of liquid through insertion of gasket between
plates and mechanical tightening by bolts and nuts, but in high temperature and high pressure environment,
gasket deterioration and leakage occur, so heat exchanger for LPG re-liquefaction device etc do not use
gasket but weld heat exchanger plate for use. On the other hand, since welded plate cannot be separated,
it is important to obtain high quality reliable welds. In addition, for better workability and production
performance, lasers that can obtain weldment with large aspect ratio and demonstrate fast welding speed
even in atmospheric condition not in vacuum condition are used in producing products.
So far, 1st report and 2nd report compared and analyzed embrittlement degrees by bead colors of weldment
through quantitative analysis of oxygen and nitrogen and measurement of hardness as fundamental
experiment for the evaluation of titanium laser welding, and evaluated the welding performance and
mechanical properties of butt welding.
This study welded specimens in various conditions by using laser and GTA welding machine to apply
edge welding to heat exchanger, and evaluated the mechanical strength through tensile stress test. As a
result of tensile test, laser weldment demonstrated tensile strength 4 times higher than GTA welds, and
porosity could be controlled by increasing and decreasing slope of laser power at overlap area.

영어초록

Titanium and titanium alloy can be reproduced immediately even if oxide films(TiO2) break apart in sea
water. Therefore, since titanium demonstrates large specific strength and outstanding resistance to stress
corrosion cracking, crevice corrosion, pitting and microbiologically influenced corrosion in sea water environment,
it has been widely applied to heat exchanger for ships. In particular, with excellent elongation, pure
titanium may be deemed as optimal material for production of heat exchanger plate which is used with
wrinkles formed for efficient heat exchange.
Conventional plate type heat exchanger prevented leakage of liquid through insertion of gasket between
plates and mechanical tightening by bolts and nuts, but in high temperature and high pressure environment,
gasket deterioration and leakage occur, so heat exchanger for LPG re-liquefaction device etc do not use
gasket but weld heat exchanger plate for use. On the other hand, since welded plate cannot be separated,
it is important to obtain high quality reliable welds. In addition, for better workability and production
performance, lasers that can obtain weldment with large aspect ratio and demonstrate fast welding speed
even in atmospheric condition not in vacuum condition are used in producing products.
So far, 1st report and 2nd report compared and analyzed embrittlement degrees by bead colors of weldment
through quantitative analysis of oxygen and nitrogen and measurement of hardness as fundamental
experiment for the evaluation of titanium laser welding, and evaluated the welding performance and
mechanical properties of butt welding.
This study welded specimens in various conditions by using laser and GTA welding machine to apply
edge welding to heat exchanger, and evaluated the mechanical strength through tensile stress test. As a
result of tensile test, laser weldment demonstrated tensile strength 4 times higher than GTA welds, and
porosity could be controlled by increasing and decreasing slope of laser power at overlap area.

참고자료

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