• Title/Summary/Keyword: Real-Time Weld Strength Evaluation

Search Result 26, Processing Time 0.02 seconds

Dissimilar Friction Welding of Elevated Temperature Materials for Pressure Vessels and Its AE Evaluation (압력용기용 고온재의 이종재 마찰용접과 AE평가)

  • Kong, Y.S.;Lee, Y.T.;Yoo, I.J.;Oh, S.K.;Lim, M.B.
    • Journal of Power System Engineering
    • /
    • v.6 no.1
    • /
    • pp.68-73
    • /
    • 2002
  • An opportunity to use the elevated temperature has been recently increasing in various elements of heat facilities or machines such as heat exchanger tubes, pressure vessels, engines of aircraft, boilers and turbines in power plants, and nuclear reactor components, etc. as machinery industry develops. Thus, the development of such elevated-temperature heat-resisting materials and the studies on their elevated-temperature materials friction welding, creep design and analysis have been considered as an important and needful fact. In this paper, friction welding optimization for 1Cr0.5Mo to STS304 and AE applications for the weld quality evaluation were investigated. The important results of this study are as follows : The techniques for dissimilar friction welding optimization of the elevated temperature materials 1Cr0.5Mo and STS304 and its real-time weld quality evaluation by AE were developed, considering on both strength and toughness. Quantitative relationship was identified among welding condition, weld quality and cumulative AE counts.

  • PDF

Study on Friction Welding of SUS431 and SCM21 for External Shaft of Ship (선외기 샤프트용 재료의 마찰용접에 관한 연구)

  • 오세규;이종환;배명주;오명석
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.17 no.4
    • /
    • pp.38-48
    • /
    • 1993
  • A study on friction welding of stainless steel bar(SUS431) to chrome molybdenum steel bar(SCM21) was accomplished experimentally through analysis for relations among friction welding conditions, tension test, hardness test, microstructure test and acoustic emission test. The results obtained are summarized as follows ; 1. Through friction welding of SUS431 bar to SCM21 bar, the optimum welding condition by considering on strength and toughness was found to be the range of heating time of 3-5 sec when the number of rotating speed of 2000rpm, heating pressure of 10kg/$mm^2$, and upsetting time of 4 sec. 2. Quantitative ralationship was identified between heating time($T_1$, sec) and tensile strength (${\sigma},\;kgf/mm^2$) of the friction welded joint and the relation equation is $\sigma$=52.62$T_1{^{0.06}}$. 3. Through AE test, quantitative relationship was confirmed between heating time($T_1$, sec) and total AE(N, counts) during welding, and the relation is computed as follows ; N=30413.6$e^{0.06T1}$. 4. It was confirmed that the quantitative ralationship exists between the tensile strength of the welded joints and AE cumulative counts. And the relation is computed as the following ; ${\sigma}$=16.37(ln N)- 116.4. 5. When ONZ=36500-41500 counts by $OT_1Z$=3~5sec, it was identified by experiment that the range of welded joint tensile strength is 55.6-57.7kgf/$mm^2$/ whose joint efficiency is more than 100%, and it was experimentally confirmed that the real-time nondestructive quality(strength) evaluation for the friction welded joints could be possible by acoustic emission technique.

  • PDF

Optimization of tube-to-bar dissimilar FRW of hydraulic valve spool steels and the weld strength properties and its AE evaluation (유공압 밸브 스풀용 강재의 관 대 봉 이종재 마찰용접의 최적화와 용접강도특성 및 AE평가)

  • 오세규;김현필;장홍근;오명석
    • Journal of Ocean Engineering and Technology
    • /
    • v.11 no.1
    • /
    • pp.24-35
    • /
    • 1997
  • The hydraulic or pneumatic valve spools become essential as the important components on the production of automatic hydraulic or pneumatic as mechanical industry has been rapidly developed. The machining precision is in necessity for manufacturing the valve spools. They could be unstable in the quality by the conventional are welding. And also they have a lot of technical problems in manufacturing because their shapes are generally small. By the precision casting process such as lost wax process, the production cost may be increased. But by the friction welding technique, they will be able to be manufactured without such problems. This paper deals with the development of dissimilar friction welding optimization for the hydraulic or pneumatic valve spool by friction welding and a new approach of on real-time qualify evaluation by AE techniques.

  • PDF

Dissimilar Friction Welding of Engine Exhaustive Valve and High Temperature Creep Prediction and Their Real-Time Evaluation by AE (엔진배기밸브의 내열강 이종재 마찰용접의 최적화와 고온 크리프의 실시간 예측 및 AE에 의한 실시간 평가)

  • Lee, Sang-Guk;Oh, Jung-Hwan;Oh, Sae-Kyoo
    • Journal of Ocean Engineering and Technology
    • /
    • v.13 no.1 s.31
    • /
    • pp.1-10
    • /
    • 1999
  • The engine exhaustive valve became essential as the important element. The dissimmilar welding method of exhaustive valve head to stem was asked for manufacturing the engine exhaustive valve, for which the electric resistance are welding has been conventionally used, resulting in poor quality of the welded joint. In this paper, not only the development of optimizing of friction welding with more reliability and more applicability but also the development of in-process real-time weld qudlity(such as strength and toughness) evaluation technique by acoustic emission for friction welding of the engine exhaustive valve(SUH3-SUH35 dissimilar steels) were perfomed. The high temperature(500, 500, 600$^{circ}$C) creep properties prediction of the friction welded joint of SUH3-SUH35 was investigated relating to the initial strain meethod(ISM) as a new approach, resulting in obtaining an experimental equation of creep life prediction.

  • PDF

Friction Welding of Dissimilar Hot Die Punch Materials and Its Creep Prediction and Quality Evaluation by AE(I) - FRW and AE+ (열간 금형펀치 제작을 위한 이종재 마찰용접과 고온크리프 실시간 예측 및 AE에 의한 품질평가(Ⅰ) -마찰용접과 AE)

  • Park, Il-Dong;Oh, Sae-Kyoo;Kim, Ji-Su
    • Journal of Ocean Engineering and Technology
    • /
    • v.13 no.3 s.33
    • /
    • pp.77-82
    • /
    • 1999
  • The compleete joining method for dissimilar hot die punch materials and its real-time evaluation method are not available at present. Brazing method has been used for joining them, but it is known that the welded joint by the brazing has the lower bonding efficiency and reliability than the diffusion welding. The friction wleding with a diffusion mechanism in bonding was applied in this study. So, this work was carried out to determine the optimal friction welding conditions and to analyze mechanical properties of friction welded joints of hot die punch materials (STD61 for the blade part of hot die punch) to alloy steel (SCM440 for the shank park of hot die punch) such as plunger. In addition, acoustic emission test was carried out during friction welding to evaluate the weld quality.

  • PDF

A Study on Application of Corrugated Invar Strake Edge in the Membrane Cargo Containment of LNG Carriers (LNG선 화물격납용기 Invar strake edge 이음부 형상 개선에 관한 연구)

  • Han, Jong-Man
    • Journal of Welding and Joining
    • /
    • v.27 no.5
    • /
    • pp.74-80
    • /
    • 2009
  • The membrane of the LNG carriers consists of thin strips of INVAR(Fe-36%Ni) steel plates, and the junction between INVAR strips is fabricated by welding. Thousands of the raised edge joints, regularly spaced, are located around all the side of the tank corner near the transverse bulkhead, and TIG welding is manually made on the top of the raised edges. Since the thickness of all the laminated edge plies is extremely thin and the weld position is under a bad accessibility, highly skilled workers are required to perform welding relatively for a long welding time. An alternative scheme for the corner membrane fabrication is proposed in the study to improve the installation workability and thus productivity. The scheme replaces the welded edges with the preformed corrugation ones. A panel strip with regularly-spaced corrugations is installed at the corner instead of the individual flat strip of which edge is vertically raised to be welded with the adjacent strip. In the study, a series of the evaluation on the corrugated edge members was performed to assess the applicability to the real LNG carrier fabrication. Opening displacement at the raised edge was experimentally examined. Elastic stiffness regressed from the displacement was nearly same in both edge types. Edge displacement and local stresses were calculated under hydrostatic pressure and temperature change due to liquefied cargo. Fatigue test was performed on both corrugated and welded edge specimens consisting of two or five plies of invar strips. Fatigue strength of the corrugated specimens was not less than that of the welded specimens.