• 제목/요약/키워드: alloy 617

검색결과 46건 처리시간 0.168초

High Temperature Oxidation Behavior and Mechanical Characteristic of Recrystallized Alloy 617 (재결정에 따른 Alloy 617의 고온 산화 거동 및 기계적 특성)

  • Lim, Jeong Hun;Jo, Tae Sun;Park, Ji Yeon;Kim, Young Do
    • Korean Journal of Metals and Materials
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    • 제48권12호
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    • pp.1078-1083
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    • 2010
  • In this study, high temperature oxidation behavior of Alloy 617 was investigated to evaluate the effect of grain size for Alloy 617. The grain size of grain-refined Alloy 617 (GR617) was reduced to $5{\mu}m$ from $71{\mu}m$ for as-received Alloy 617 (AR617) by recrystallization after cold rolling. After high temperature aging, the oxide layers of AR617 and GR617 consisted of $Cr_2O_3$ external oxide scale and $Al_2O_3$ internal oxide. The external oxide scale resulted in a Cr-depleted zone and a carbide free zone below the scale. The depth of the carbide free zone was deeply formed in GR617. On the other hand, the depth of the internal oxide layer in GR617 was shorter than that in AR617. After a 3-point bending test, crack propagation of GR617 was more restricted than that of AR617 because of the different microstructure of the internal oxide.

An Experimental Investigation on Low Cycle Fatigue Behavior of Alloy 617 Base Metal and Alloy 617/Alloy 617 Weld Joints (Alloy 617 모재와 용접부재의 저사이클피로 거동에 관한 실험적 고찰)

  • Choi, Pil-Ho;Kim, Seon-Jin;Kim, Woo-Gon;Kim, Min-Hwan
    • Journal of Power System Engineering
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    • 제18권5호
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    • pp.115-121
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    • 2014
  • Alloy 617 is the one of the leading candidate materials for intermediate heat exchangers(IHX) of a very high temperature reactor(VHTR) system. Some of the components are joined by many welding techniques and therefore the welded joints are inevitable in the construction of systems. In the present paper, the low cycle fatigue(LCF) behaviors of Alloy 617 base metal(BM) and the gas tungsten arc welded (GTAWed) weld joints(WJ) are investigated experimentally under strain controlled LCF tests. Fully axial total-strain controlled tests have been conducted at room temperature with total strain ranges of 0.6, 0.9, 1.2 and 1.5%. The weld joints have shown a lower fatigue lives compared with base metals at all the testing conditions. The weld joints have shown a higher cyclic stress response behavior than base metal. Both BM and WJ exhibited cyclic strain hardening behavior, depending on the total strain range. In addition, the strain-life parameters for BM and WJ were determined, based on Coffin-Manson equations.

Evaluation of Fatigue Life on Alloy 617 Base Metal and Alloy 617/Alloy 617 Weld Joints under Low Cycle Fatigue Loading (저사이클피로 하중하의 Alloy 617 모재와 용접부재에 대한 피로 수명 평가)

  • Dewa, Rando Tungga;Kim, Seon-Jin;Kim, Woo-Gon;Kim, Min-Hwan
    • Journal of Power System Engineering
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    • 제18권5호
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    • pp.122-128
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    • 2014
  • Generally, the mechanical components and structures are joined by many welding techniques, and therefore the welded joints are inevitable in the construction of structures. The Alloy 617 was initially developed for high temperature applications above $800^{\circ}C$. It is often considered for use in aircraft and gas turbines, chemical manufacturing components, and power generation structures. Especially, the Alloy 617 is the primary candidate for construction of intermediate heat exchanger (IHX) on a very high temperature reactor (VHTR) system. In the present paper, the low cycle fatigue (LCF) life of Alloy 617 base metal (BM) and the gas tungsten arc welded (GTAWed) weld joints (WJ) are evaluated by using the previous experimental results under strain controlled LCF tests. The LCF tests have been performed at room temperature with total strain ranges of 0.6, 0.9, 1.2 and 1.5%. The LCF lives for the BM and WJ have been evaluated from the Coffin-Manson and strain energy based life methods. For both the BM and WJ, the LCF lives predicted by both Coffin-Manson and strain energy based life methods was found to well coincide with the experimental data.

Low Cycle Fatigue Behavior of Alloy617 Weldment at 850℃ (850℃에서의 Alloy 617 용접재의 저사이클 피로 특성)

  • Hwang, Jeong Jun;Kim, Seon Jin;Kim, Woo Gon;Kim, Eung-Seon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • 제41권3호
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    • pp.193-198
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    • 2017
  • Alloy 617 is one of the primary candidate materials to be used in a very high temperature reactor (VHTR) system as an intermediate heat exchanger (IHX). To investigate the low cycle fatigue behavior of Alloy 617 weldments at a high temperature of $850^{\circ}C$, fully reversed strain-controlled fatigue tests were conducted with the total strain values ranging from 0.6~1.5%. The weldment specimens were machined using the weld pads fabricated with a single V-grove configuration by gas tungsten arc welding (GTAW) process. The fatigue life is reduced as the total strain range increases. For all testing conditions, the cyclic stress response behavior of the Alloy 617 weldments exhibited the initial cyclic strain hardening phenomenon during the initial small number of cycles. Furthermore, the overall fatigue cracking and the propagation or cracks showed a transgranular failure mode.

Evaluation of Hydrogen Embrittlement Behavior in INCONEL Alloy 617 by Small Punch Test (소형펀치 시험법을 이용한 INCONEL Alloy 617의 수소취화거동 평가)

  • Seo, Hyon-Uk;Ma, Young-Hwa;Yoon, Kee-Bong
    • Journal of Hydrogen and New Energy
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    • 제21권4호
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    • pp.340-345
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    • 2010
  • For the conversion into hydrogen society, not only studying facilities of hydrogen production, storage, transportation and charging system but also developing technique of ensuring safety are essentially needed. Hence, for the first step of that, evaluated the hydrogen embrittlement of Inconel alloy 617, Ni-based super heat-resisting alloy, by small punch test. Prepared the various specimens through changing electrochemical charging time and measured the toughness degradation of the specimens by small-punch test. The analysis of hydrogen embrittlement behavior were carried out by investigating the fractured surface of specimens. This study has significance on revealing mechanism of hydrogen embrittlement behavior and the factor affecting hydrogen embrittlement in the future study.

Macro and Microscopic Investigation on Fracture Specimen of Alloy 617 Base Metal and Weldment in Low Cycle Fatigue Regime (저사이클 피로 영역에서의 Alloy 617 모재와 용접재의 파괴 시험편에 대한 거시적 및 미시적 관찰)

  • Kim, Seon Jin;Dewa, Rando Tungga;Kim, Woo Gon;Kim, Eung Seon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • 제40권6호
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    • pp.565-571
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    • 2016
  • This paper investigates macro- and microscopic fractography performed on fracture specimens from low cycle fatigue (LCF) testings through an Alloy 617 base metal and weldments. The weldment specimens were taken from gas tungsten arc welding (GTAW) pad of Alloy 617. The aim of the present study is to investigate the macro- and microscopic aspects of the low cycle fatigue fracture mode and mechanism of Alloy 617 base metal and GTAWed weldment specimens. Fully axial total strain controlled fatigue tests were conducted at room temperature with total strain ranges of 0.6, 0.9, 1.2 and 1.5%. Macroscopic fracture surfaces of Alloy 617 base metal specimens showed a flat type normal to the fatigue loading direction, whereas the GTAWed weldment specimens were of a shear/star type. The fracture surfaces of both the base metal and weldment specimens revealed obvious fatigue striations at the crack propagation regime. In addition, the fatigue crack mechanism of the base metal showed a transgranular normal to fatigue loading direction; however, the GTAWed weldment specimens showed a transgranular at approximately $45^{\circ}$ to the fatigue loading direction.

Suggestion and Evaluation of a Multi-Regression Linear Model for Creep Life Prediction of Alloy 617 (Alloy 617의 장시간 크리프 수명 예측을 위한 다중회귀 선형 모델의 제안 및 평가)

  • Yin, Song-Nan;Kim, Woo-Gon;Jung, Ik-Hee;Kim, Yong-Wan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • 제33권4호
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    • pp.366-372
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    • 2009
  • Creep life prediction has been commonly used by a time-temperature parameter (TTP) which is correlated to an applied stress and temperature, such as Larson-Miller (LM), Orr-Sherby-Dorn (OSD), Manson-Haferd (MH) and Manson-Succop (MS) parameters. A stress-temperature linear model (STLM) based on Arrhenius, Dorn and Monkman-Grant equations was newly proposed through a mathematical procedure. For this model, the logarithm time to rupture was linearly dependent on both an applied stress and temperature. The model parameters were properly determined by using a technique of maximum likelihood estimation of a statistical method, and this model was applied to the creep data of Alloy 617. From the results, it is found that the STLM results showed better agreement than the Eno’s model and the LM parameter ones. Especially, the STLM revealed a good estimation in predicting the long-term creep life of Alloy 617.

Taylor Series-Based Long-Term Creep-Life Prediction of Alloy 617 (Taylor 급수를 이용한 617 합금의 장시간 크리프 수명 예측)

  • Yin, Song-Nan;Kim, Woo-Gon;Park, Jae-Young;Kim, Soen-Jin;Kim, Yong-Wan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • 제34권4호
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    • pp.457-465
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    • 2010
  • In this study, a Taylor series (T-S) model based on the Arrhenius, McVetty, and Monkman-Grant equations was developed using a mathematical analysis. In order to reduce fitting errors, the McVetty equation was transformed by considering the first three terms of the Taylor series equation. The model parameters were accurately determined by a statistical technique of maximum likelihood estimation, and this model was applied to the creep data of alloy 617. The T-S model results showed better agreement with the experimental data than other models such as the Eno, exponential, and L-M models. In particular, the T-S model was converted into an isothermal Taylor series (IT-S) model that can predict the creep strength at a given temperature. It was identified that the estimations obtained using the converted ITS model was better than that obtained using the T-S model for predicting the long-term creep life of alloy 617.