• Title/Summary/Keyword: Fe-Ni steel

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Sintering Characteristics of 304 and 316L Stainless Steel Fine Powder (304 및 316L 스테인레스강 미립 분말의 소결 특성)

  • Lim, Tae-Whan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.6
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    • pp.1555-1559
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    • 2008
  • The characteristics of 304 (Fe-18%Cr-12%Ni) and 316L (Fe-18%Cr-13%Ni-2.4%Mo) austenite stainless-steel compacts sintered with $5{\sim}15{\mu}m$ powder were investigated and the results led to the following conclusions: (1) When the sintering time was 3.6ks, the relative density of sintered compacts was $95{\sim}98%$, regardless of any other sintering condition. (2) When a vacuum sintering was done with $5{\mu}m$ stainless steel powders, almost fully-dense sintered compacts were obtained at is = 57.6ks. (3) The amount of residual oxygen in 304 and 316L sintered compacts was $0.5{\sim}0.6%$, regardless of sintering atmosphere. (4) The amount of residual oxygen in the vacuum sintered compact decreased more than 0.3 % due to addition of carbon powder, thereby reducing the formation of oxides. Furthermore, the addition of carbon improved the density of sintered compact, which enables us to make a fully-dense high performance sintered compact.

Evaluation of Corrosion Resistance of Materials for Supercritical Carbon Dioxide Power Plant (초임계 이산화탄소 발전용 소재의 고온 내식성 평가)

  • Chae, Hobyung;Seo, Sukho;Jung, Yong Chan;Lee, Soo Yeol
    • KEPCO Journal on Electric Power and Energy
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    • v.1 no.1
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    • pp.109-113
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    • 2015
  • 초임계 이산화탄소 발전 시스템 구축을 위해서는 고온, 고압의 열악한 환경에 노출되는 터빈, 열 교환기, 압축기와 같은 핵심 부품들의 내식성 평가는 반드시 수행되어야 한다. 이를 위해 후보소재 3종 Ferritic-Martensitic Steel (T92), Austenitic Steel (SS316L), Ni-based Alloy (IN738LC)를 선정하여 고온의 유사 초임계 $CO_2$ 발전 환경에서의 내식성 평가를 진행하였다. $600^{\circ}C$, $700^{\circ}C$의 2개의 온도 구간에서 $CO_2$ 분위기를 조성하여 800 시간 동안 노출시킨 뒤, Weight Change, Surface Morphology, Cross Section, Composition을 분석하였다. Cr-rich Protective Layer를 형성하는 Ni-based Alloy와 Fe/Cr-rich oxide를 형성하는 Austenitic Steel은 우수한 부식 저항성을 보인 반면에 Ferritic-Martensitic Steel은 높은 Weight Change와 Fe-rich Non-Protective Oxide가 관찰되어 상대적으로 낮은 부식 저항성을 보였다.

Characterization of Ni-Fe Alloy Electrodeposited Electrode for Alkaline Water Electrolysis (알칼라인 수전해용 Ni-Fe 합금 전착 전극의 특성)

  • AN, DA-SOL;BAE, KI-KWANG;PARK, CHU-SIK;KIM, CHANG-HEE;KANG, KOUNG-SOO;CHO, WON-CHUL;CHO, HYUN-SEOK;KIM, YOUNG-HO;JEONG, SEONG-UK
    • Transactions of the Korean hydrogen and new energy society
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    • v.27 no.6
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    • pp.636-641
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    • 2016
  • Alkaline water electrolysis is commercial hydrogen production technology. It is possible to operate MW scale plant. Because It used non-precious metal for electrode. But It has relatively low current density and low efficiency. In this study, research objective is development of anode for alkaline water electrolysis with low cost, high corrosion resistance and high efficiency. Stainless steel 316L (SUS 316L) was selected for a substrate of electrode. To improve corrosion resistance of substrate, Nickel (Ni) layer was electrodeposited on SUS 316L. Ni-Fe alloy was electrodeposited on the passivated Ni layer as active catalyst for oxygen evolution reaction(OER). We optimized preparation condition of Ni-Fe alloy electrodeposition by changing current density, electrodeposition time and composition ratio of Ni-Fe electrodeposition bath. This electrodes were electrochemically evaluated by using Linear sweep voltammetry (LSV) and Cyclic voltammetry (CV). The Ni-Fe alloy (Ni : Fe = 1 : 1) showed best activity of OER. The optimized electrode decreased overpotential about 40% at $100mA/cm^2$ compared with Ni anode.

Fabrication of Graded-Boundary Ni/Steel Material by Laser Beam (레이저빔에 의한 조성구배계면 Ni/Steel 재료의 제조)

  • 안재모;김도훈
    • Laser Solutions
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    • v.2 no.1
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    • pp.22-29
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    • 1999
  • This work was carried out as a fundamental experiment to fabricate a Graded-Boundary Ni/Steel material using a laser beam. A Ni sheet was placed on a steel substrate, and then a series of high power $CO_2$ laser beams were irradiated on the surface in order to produce a homogeneous alloyed layer. The processing parameters were : 4 ㎾ laser power, 2m/min traverse speeds, -2mm defocuing, 17 l/min sheiding gas flow rates. The sequential repetition of the laser surface alloying treatment up to 4 times, resulted in about 5mm thick of fair compositional gradient systems. In order to determine the microstructure, phase and compositional profiles in this material, optical microscopy, XRD and EDS were used. The compositions varied from 66% to 0% for Ni and 34% to 100% for Fe in this material The microstructures were typical morphologies of rapid solidification and solid-state cooling. Since compressive stress was formed in the heat affected region due to martensitic transformation, while relative tensile stress was developed in the alloyed region, cracks were formed between the alloyed region and the substrate region.

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The influence of spraying conditions to the coating layer properties of Fe-Cr-Ni-Mo-Si-B alloy using the HVOF (HVOF를 이용한 Fe-Cr-Ni-Mo-Si-B계 고성능 합금 용사층의 특성에 미치는 용사조건의 영향)

  • 권기봉;조대형;장영권;백영남
    • Journal of the Korean institute of surface engineering
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    • v.35 no.1
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    • pp.5-10
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    • 2002
  • This study was performed to investigate the influence of spraying condition to the coating layer properties of Fe-Cr-Ni-Mo-Si-B alloy using the HVOF. The investigations, such as thickness measurement, surface roughness, hardness, friction coefficient, resistance of corrosion were carried out. Matrix is prepared by gritting and coating layer is made of Fe-Cr-Ni-Mo-Si-B alloy powder using HVOF. Alumina gritting layers are superior to steel gritting layers. The less spaying distance, the more coating layer properties confirmed. The optimum spraying condition, in this study, was proved as 13inch spraying distance with feed rate 350rpm (78g/min).

Welding Residual Stress and Strength of Thick 9% Nickel Steel Plate (9% 니켈강 후판 용접부의 강도 및 잔류응력)

  • Kim, Young-Kyun;Kim, Young-Wann;Kim, Jae-Hoon
    • Journal of Power System Engineering
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    • v.18 no.4
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    • pp.85-90
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    • 2014
  • In this paper, the transient thermal and residual stress analysis of the welding of 9% Ni steel plates using the FEA software ABAQUS are presented. The 9% Ni steel plates are welded manually with welding consumables of 70% Ni based Inconel type super-alloys (YAWATA WELD B (M)), producing a multi-pass/multi-layer butt weld. For these materials, temperature dependant mechanical and thermal material properties are used in the analysis. The back gouging is considered in welding process simulation. The FE thermal results are validated by comparing the real fusion profile and heat affected zone (HAZ). In addition, the continuous indentation test was conducted to measure the strength of base metal, HAZ and weld metal.

Effect of dilution on micro hardness of Ni-Cr-B-Si alloy hardfaced on austenitic stainless steel plate for sodium-cooled fast reactor applications

  • Balaguru, S.;Murali, Vela;Chellapandi, P.;Gupta, Manoj
    • Nuclear Engineering and Technology
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    • v.52 no.3
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    • pp.589-596
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    • 2020
  • Many components in the assembly section of Sodium-cooled Fast Reactor are made of good corrosionresistant 316 LN Stainless Steel material. To avoid self-welding of the components with the coolant sodium at elevated temperature, hardfacing is inevitable. Ni-based colmonoy-5 is used for hardfacing due to its lower dose rate by Plasma Transferred Arc process due to its low dilution. Since Ni-Cr-B-Si alloy becomes very fluidic while depositing, the major height of the weld overlay rests inside the groove. Hardfacing is also done over the plain surface where grooving is not possible. Therefore, grooved and ungrooved hardfaced specimens were prepared at different travel speeds. Fe content at every 100 ㎛ of the weld overlay was studied by Energy Dispersive Spectroscopy and also the micro hardness was determined at those locations. A correlation between iron dilution from the base metal and the micro hardness was established. Therefore, if the Fe content of the weld overlay is known, the hardness at that location can be obtained using the correlation and vice-versa. A new correlation between micro hardness and dilution coefficient is obtained at different locations. A comparative study between those specimens is carried out to recommend the optimum travel speed for lower dilution.

Austenite Stability and Mechanical Properties of Nanocrystalline FeNiCrMoMnSiC Alloy Fabricated by Spark Plasma Sintering (방전플라즈마소결로 제조된 나노결정 FeNiCrMoMnSiC 합금의 오스테나이트 안정성과 기계적 특성)

  • Park, Jungbin;Jeon, Junhyub;Seo, Namhyuk;Kim, Gwanghun;Son, Seung Bae;Lee, Seok-Jae
    • Journal of Powder Materials
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    • v.28 no.4
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    • pp.336-341
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    • 2021
  • In this study, a nanocrystalline FeNiCrMoMnSiC alloy was fabricated, and its austenite stability, microstructure, and mechanical properties were investigated. A sintered FeNiCrMoMnSiC alloy sample with nanosized crystal was obtained by high-energy ball milling and spark plasma sintering. The sintering behavior was investigated by measuring the displacement according to the temperature of the sintered body. Through microstructural analysis, it was confirmed that a compact sintered body with few pores was produced, and cementite was formed. The stability of the austenite phase in the sintered samples was evaluated by X-ray diffraction analysis and electron backscatter diffraction. Results revealed a measured value of 51.6% and that the alloy had seven times more austenite stability than AISI 4340 wrought steel. The hardness of the sintered alloy was 60.4 HRC, which was up to 2.4 times higher than that of wrought steel.

Impurity Pick-Up for the Preparation of NiCuZn Ferrite Powder Using Ball Milling Process (NiCuZn Ferrite 분말제조에 있어서 Ball Mill 분쇄 공정 중에 혼입되는 불순물의 함량)

  • 고재천;류병환
    • Journal of the Korean Magnetics Society
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    • v.9 no.4
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    • pp.217-222
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    • 1999
  • The pick up impurity was studied for preparing the NiCuZn ferrite powder by a ball milling method that usually uses in the industrial ceramic process. The raw materials of NiO, CuO, ZnO, and $Fe_2O_3$ powder were weighted according to various spinel composition and mixed for 18 hrs by a wet ball milling method after that the slurry was followed by spray dried and calcined at $700^{\circ}C$ 3 hrs. The calcined NCZF powder was finally ball milled during 65 hrs as same method. The stainless steel ball and jar are used as mixing and milling equipment and the solid concentration of the slurry was 25 vol%. The impurities, stainless steel pickup, were effected by the composition of raw materials especially iron oxide, nickel oxide in the mixing process and by the rate of calcine of NiCuZn ferrite in final milling process. The empirical equation of stainless steel pickup was driven in the wet ball milling system. Finally, the composition of NiCuZn ferrite could be controlled by the empirical equation.

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Morphologies of Brazed NiO-YSZ/316 Stainless Steel Using B-Ni2 Brazing Filler Alloy in a Solid Oxide Fuel Cell System

  • Lee, Sung-Kyu;Kang, Kyoung-Hoon;Hong, Hyun-Seon;Woo, Sang-Kook
    • Journal of Powder Materials
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    • v.18 no.5
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    • pp.430-436
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    • 2011
  • Joining of NiO-YSZ to 316 stainless steel was carried out with B-Ni2 brazing alloy (3 wt% Fe, 4.5 wt% Si, 3.2 wt% B, 7 wt% Cr, Ni-balance, m.p. 971-$999^{\circ}C$) to seal the NiO-YSZ anode/316 stainless steel interconnect structure in a SOFC. In the present research, interfacial (chemical) reactions during brazing at the NiO-YSZ/316 stainless steel interconnect were enhanced by the two processing methods, a) addition of an electroless nickel plate to NiO-YSZ as a coating or b) deposition of titanium layer onto NiO-YSZ by magnetron plasma sputtering method, with process variables and procedures optimized during the pre-processing. Brazing was performed in a cold-wall vacuum furnace at $1080^{\circ}C$. Post-brazing interfacial morphologies between NiO-YSZ and 316 stainless steel were examined by SEM and EDS methods. The results indicate that B-Ni2 brazing filler alloy was fused fully during brazing and continuous interfacial layer formation depended on the method of pre-coating NiO-YSZ. The inter-diffusion of elements was promoted by titanium-deposition: the diffusion reaction thickness of the interfacial area was reduced to less than 5 ${\mu}m$ compared to 100 ${\mu}m$ for electroless nickel-deposited NiO-YSZ cermet.