• Title/Summary/Keyword: 스테인리스강 탱크

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Characteristics of Fiber Laser Welding on STS304L for GTT MARK III Membrane (GTT MARK III 스테인리스강 STS304L의 파이버 레이저 용접특성)

  • Kim, Jong-Do;Lee, Chang-Je;Song, Moo-Keun
    • Journal of Advanced Marine Engineering and Technology
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    • v.36 no.8
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    • pp.1069-1075
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    • 2012
  • Laser is high density heat source, so it can make high speed welding with minimum heat input possible. Especially the high power fiber laser is recently commercialized and has high beam quality and the smallest system size compared with conventional laser due to it's unique oscillating mechanism. Because of these advantages it's thought that the most suitable heat source for LNG cargo tank welding precess which has to be conducted inside of ships. In this study fiber laser was used for welding of stainless steel for LNG carrier to applicate laser welding technique for shipbuilding industry. 1.2mmt STS304L of austenite stainless steel which apply to cargo tank was used for fiber laser welding. Butt and lap welding was conducted changing laser power, welding speed, then penetration characteristic was analyzed and optimal parameters for each materials. Consequently, we found that same or better mechanical properties were obtained in weld compared to base metal.

Characteristics of Starship System Development (Starship 시스템 개발 특징)

  • Yoo, Jaehan
    • Journal of the Korean Society of Propulsion Engineers
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    • v.25 no.5
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    • pp.53-64
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    • 2021
  • SpaceX has lowered rocket launch cost innovatively and put first stage reuse to the practical use with Falcon 9. Now the company is developing Starship system that is fully reusable with the heaviest payload in the world. So the system can lower the cost much more and fulfull more diverse mission. For the system the company have developed Raptor engine which is a full-flow staged combustion cycle one with methane fuel. And for the full reusability the company is manufacturing and testing the system prototypes with the barely used technologies such as stainless steel tank, belly flop and retropropulsion during descent. In this study the specification, missions and design features of the system are investigated. Also the development processes of Raptor engine and initial 13 Starship prototypes, which have been manufactured very rapidly, are presented.

The Evaluation of Mechanical Properties and Fatigue Life for Domestic 304 Stainless Steel Used as Membrane Material in LNG Storage Tank (LNG저장탱크의 멤브레인용 국산 304 스테인리스강의 기계적성질 및 피로수명 평가)

  • Kim, Hyeong-Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.10
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    • pp.1644-1650
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    • 2001
  • Mechanical properties of domestic 374 stainless steel have been evaluated fur membrane material used in LNG storage tank. LNG tank is operated around -162$^{\circ}C$. The temperature of membrane depends on LNG level. Accordingly, the membrane material is deteriorated by variation of liquid pressure and temperature. Tensile test and fatigue life test were performed at room temperature and -l62$^{\circ}C$ per code requirements. Especially the biaxial fatigue life test was conducted with shaped membrane sheet at a thermal strain of $\Delta$T=190$^{\circ}C$ The test results obtained with the domestic 304 stainless steel showed better properties compared to the values required by code.

Interpretation for Band-Type Indication on Radiography of 9% Ni Steel Welds for LNG Storage Tanks (액화천연가스 저장탱크 9% 니켈강 용접부의 방사선투과시험 필름에 나타나는 밴드형상의 지시 해석)

  • Lee, Seung-Hyun;Lee, Seung-Rim;Lee, Young-Soon
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.5
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    • pp.479-483
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    • 2010
  • 9% nickel alloy steels used for LNG, cryogenic liquid, storage tank are welded with dissimilar Inconel or Hastelloy welding rod and the weldment shows similar characteristic with the dissimilar metal weld of low carbon steel and austenitic stainless steel. Band type indications are sometimes shown on the film during radiography test of the weldments. Thus this study identified whether the indications are non-relevant indications through material, radiographic test, ultrasonic test, liquid penetrant test and microstructure analysis and also proposed radiography film interpretation and cause of band type indications.

Evaluation of Creep-Fatigue Integrity for High Temperature Pressure Vessel in a Sodium Test Loop (소듐 시험루프 내 고온 압력용기의 크리프-피로 건전성 평가)

  • Lee, Hyeong-Yeon;Lee, Dong-Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.8
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    • pp.831-836
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    • 2014
  • In this study, high temperature integrity evaluation on a pressure vessel of the expansion tank operating at elevated temperature of $510^{\circ}C$ in the sodium test facility of the SEFLA(Sodium Thermal-hydraulic Experiment Loop for Finned-tube Sodium-to-Air heat exchanger) to be constructed at KAERI has been performed. Evaluations of creep-fatigue damage based on a full 3D finite element analyses were conducted for the expansion tank according to the recent elevated temperature design codes of ASME Section III Subsection NH and French RCC-MRx. It was shown that the expansion tank maintains its integrity under the intended creep-fatigue loads. Quantitative code comparisons were conducted for the pressure vessel of austenitic stainless steel 316L.

A Study on the Fatigue Strength of Lap Weld of LNG Tank (LNG탱크 겹침용접부의 피로강도에 관한 연구)

  • Kim, Jong-Ho
    • Journal of Ocean Engineering and Technology
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    • v.13 no.3 s.33
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    • pp.29-35
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    • 1999
  • At the design of Mark III membrane type LNG tank, an analytical and experimental approach on the fatigue strengths of membrane and its welds are very important in order to assist designers and surveyors. In this study, fatigue tests of lap weld of Mark III membrane type LNG tank were carried out and cumulative damage factor was calculated in order to estimate the fatigue life by probability density function and rule methods. It contained the following tests and reviews : 1) The fatigue tests of lap weld of stainless steel according to statistical testing method recommended by JSME, 2)Preparation of S-N curve for lap welds considering the statistical properties of the results of fatigue tests. 3) Procedure for estimating the initiation life of fatigue crack of lap welds under variable loads by the rule lf classification society and probability density function, 4) Guideline for inspection of lap welds fo membrane type LNG tank.

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A Study on Low Temperature Strength and Fatigue Strength of Austenitic Stainless Steel for Membrane Type LNG Tank (멤브레인형 LNG 탱크용 오스테나이트계 스테인리스강의 저온강도 및 피로강도에 관한 연구)

  • 이해우;신용택;박정웅;이재원;강창룡
    • Journal of Welding and Joining
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    • v.17 no.3
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    • pp.50-54
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    • 1999
  • Feasibility study of the application of a developed annealed austenitic stainless steel at cryogenic temperature has been performed for membrane tank of LNG ship. Chemical properties of developed stainless steel are compared with a domestic commercial stainless steel and a foreign stainless steel which are used for LNG ships. Tensile properties at cryogenic temperature and fatigue strength at room temperature are measured for but and lap joints which are TIG welded specimens. Developed stainless steel having a small amount of titanium component shows the finest grain size in the HAZ, compared with the other stainless steel studied. Tensile strength, elongation and fatigue strength of the developed stainless steel are equal to those of the foreign stainless steel studied and are higher than the domestic commercial stainless steel studied.

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Comparison on Autogenous Weldability of Stainless Steel using High Energy Heat Source (고에너지 열원에 따른 스테인리스강의 제살용접특성 비교)

  • Kim, Jong-Do;Lee, Chang-Je;Song, Moo-Keun
    • Journal of Advanced Marine Engineering and Technology
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    • v.36 no.8
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    • pp.1076-1082
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    • 2012
  • Today the welding for LNG carrier is known to be possible using arc and plasma arc welding process. But because of the lower energy density, arc welding is inevitable to multi-pass welding for thick plate and has a limit of welding speed compared to laser which is high energy density heat source. When thick plate is welded, weld defect by multi-pass welding and heat-affected zone by high heat-input were formed. Therefore one-pass welding by key-hole has been considered to work out the problems. It is possible for Laser, electron beam, plasma process to do key-hole welding. Nowadays, plasma process has been used for welding membrane of cargo tank for LNG carrier instead of arc process. Recently, many studies have examined to apply laser process to welding of membrane. In this paper, weldability, microstructure and mechanical properties of stainless steel for LNG carrier welded by fiber laser were compared to those by plasma. As a result, although the laser welding has several times faster speed, similar properties and smaller weld and heat affected zone were obtained. Consequently, this study proves the superiority of fiber laser welding for LNG carrier.

A Study on the Weld Part Fracture Toughness of Austenite Type Stainless Steel for Cryogenic Liquid Nitrogen Storage Tank (초저온 액화질소 저장탱크 오스트나이트계 스테인리스강의 용접부의 파괴인성 연구)

  • Kim, Young-Deuk;Choi, Dong-Jun;Park, Hyung-Wook;Cho, Jong-Rae;Bae, Won-Byoung
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.6
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    • pp.802-808
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    • 2011
  • One of the important mechanical properties of cryogenic temperature structure material is fracture toughness. Research on normalization of fracture toughness test method is becoming very important issue with development of cryogenic structural elements. Specially, mechanical properties estimation by each micro-structure of welding department is important because it can cause unstable fracture when use under cryogenic environment in case of welding department. In this study, fracture toughness estimation test was carried out to unloading compliance method and sensitization heat-tread minimized test specimen at liquid nitrogen (77K), liquid helium (4K), 293K temperature to STS-316L base metal and weld metal.