• Title, Summary, Keyword: low-carbon steel

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Dissimilar Metal Welding of Austenite Stainless Steel and Low Carbon Steel using CW Nd:YAG Laser (CW Nd:YAG 레이저를 이용한 저 탄소강과 오스테나이트계 스테인레스강의 이종금속 용접)

  • Yoo Young Tae;Shin Ho Jun;Ahn Dong-Gyu;Im Kiegon
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.8
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    • pp.17-26
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    • 2005
  • Dissimilar-metal welds(DHWs) are used widely in various industrial applications due to the pratical importance from the technical and economic aspect. However, DMWs have several fabricative and metallurgical drawbacks that can often lead to in-service failures. For example, the most pronounced fabrication faults are hot cracks. Recently, DMWs have used the various of heat source to decrease such as faults. In this paper, the weldability on dissimilar metal welds of Austenite stainless steel and Low carbon steel using a continuous wave Nd:YAG laser was experimentally investigated. Experiments were conducted to determine effects of welding parameters, on eliminating or reducing the extent welding zone formation at dissimilar metal welds and to optimize those parameters that have the most influence parameters such as focus length, power, beam speed, shielding gas, and wave length of laser.

Effects of Alloy Additions and Annealing Parameters on Microstructure in Cold-Rolled Ultra Low Carbon Steels (극저탄소 냉연강판에서 합금원소 및 어닐링조건이 미세조직에 미치는 영향)

  • Jeong, Woo Chang
    • Journal of the Korean Society for Heat Treatment
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    • v.17 no.2
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    • pp.78-86
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    • 2004
  • Effects of the annealing parameters on the formation of ferrites transformed at low temperatures were studied in cold-rolled ultra low carbon steels with niobium and/or chromium. Niobium and chromium were found to be effective in the formation of the low temperature transformation ferrites. The low temperature transformation ferrites more easily formed when both higher annealing temperature and longer annealing time, allowing substitutional alloying elements to distribute between phases, are in combination with faster cooling rate. It was found from EBSD study that the additions of niobium or chromium resulted in the increase in the numbers of high angle grain boundaries and the decrease in those of the low angle grain boundaries in the microstructures. Both granular bainitic ferrite and bainitic ferrite were characterized by the not clearly etched grain boundaries in light microscopy because of the low angle grain boundaries.

Friction and Wear at Dry Sliding Low Carbon Steel Surfaces Under Vacuum Conditions (진공분위기 내에서 건조마찰 미끄럼운동을 하는 저탄소강 표면의 마찰마모 특성)

  • 공호성;윤의성;권오관
    • Tribology and Lubricants
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    • v.10 no.3
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    • pp.29-38
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    • 1994
  • The friction and wear of mild steel at dry sliding surfaces under different vacuum conditions have been investigated to understand the wear mechanisms. For the test, a ball-ondisk typed wear-rig has been built and implemented, allowing control of sliding speed, load and vacuum. Results show that, at a high sliding velocity, friction of low carbon steel (SS41) under a high vacuum is much higher than that of ambient condition and wear is much severer. It is due to lack of effective oxidation film formation on which steel surfaces could protect themselves against the severe wear. It has been shown, however, that there is a critical regime with contact conditions (at a low sliding velocity, a low load, and under a medium vacuum) at which effective, protective films of low carbon steel have been built on the surfaces in a friction process with a self-regulating way, resulting in both very low coefficients of friction (about 0.3) and mild wear. In order to investigate the protective films on steel surfaces, the worn surfaces and the wear debris have been experimentally analyzed with SEM, AES/SAM and XRD. A theoretical analysis of frictional heating at sliding surfaces, and an experimental analysis of the influence of oxidation wear under various vacuum conditions are described. The important variables on which self-formations of protective films at dry sliding surfaces depend, and the wear mechanisms are also investigated.

Constitutive model coupled with damage for carbon manganese steel in low cycle fatigue

  • Huang, Zhiyong;Wang, Qingyuan;Wagner, Daniele;Bathias, Claude
    • Steel and Composite Structures
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    • v.17 no.2
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    • pp.185-198
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    • 2014
  • Carbon-manganese steel A42 (French standards) is used in steam generator pipes of nuclear center and subject to low cycle fatigue (LCF) loads. In order to obtain the material LCF behavior, the tests are implemented in a hydraulic fatigue machine. The LCF plastic deformation and cyclic stress in macroscope have been influenced by the accumulated low cycle fatigue damage. The constitutive kinematic and isotropic hardening modeling is modified with coupling fatigue damage to describe the fatigue behavior. The improved model seems to be good agreement with the test results.

Effects of Mo, V addition on Linear Thermal Expansion Coefficient and Hardness of Low Thermal Expansion Cast Steel (주강계 저열팽창 주조합금의 열팽창 계수와 경도에 미치는 Mo, V 첨가의 영향)

  • Kim, Young-Han;Yoon, Eui-Park;Moon, Byoung-Moon;Hong, Young-Myung
    • Journal of Korea Foundry Society
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    • v.18 no.5
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    • pp.467-473
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    • 1998
  • For enhancing the mechanical properties of LTE (low thermal expansion) cast steel, systematic researches have been carried out. The effects of alloying elements such as vanadium, molybdenum and carbon on the hardness and linear thermal expansion coefficient were investigated. In the range of $0.5{\sim}2.3\;wt%$ carbon, addition of 1.73 wt% carbon caused hardness increase due to the formation of eutectic carbide having high hardness but over the range of 1.73 wt% carbon, hardness was decreased. Thermal expansion coefficient increases with carbon contents. In the LTE cast steel containing 0.6 wt% carbon, hardness increased up to 1.96 wt% vanadium addition. But over the range of 1.96 wt% vanadium hardness was decreased by coarse eutectic carbide. Thermal expansion coefficient of LTE cast steel containing 0.6 wt%carbon moderately increased with increasing vanadium contents. There was no significant variation of hardness and thermal expansion coefficient according to molybdenum content in LTE cast steel.

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The Effect of Microstructure and Mechanical Property with Cooling Rapid in Boron-Treated Low Carbon Low Alloy Steel (저탄소.저합금 보론 첨가강의 냉각속도에 따른 미세조직과 기계적 성질의 영향)

  • Son, J.Y.;Lee, G.D.;Kim, S.G.;Kim, Y.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.207-210
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    • 2008
  • The effects of boron additions in steels have long been recognized as very important, mainly with respect to hardnability of heat treatable steels. we investigated the effect of the microstructure and mechanical properties with cooling condition after heat treatment of the boron-treated(${\fallingdotseq}8{\sim}18ppm$) low carbon(${\fallingdotseq}0.2%C$) low alloy steel. The specimens were austenitised for 10 min at $910^{\circ}C$, cooled for the various periods of time from 10 sec to 30 sec or with water after forming for 15 sec. After cooling, mechanical properties were measured by tensile test and hardness test. For analysis of microstructure, Optical were carried out.

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Dry sliding wear behavior of plain low carbon dual phase steel by strain hardening and oxidation (가공경화와 산화층 형성에 의한 이상조직 저탄소강의 건식 미끄럼 마멸 거동)

  • Yu, H.S.;Kim, Y.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.149-152
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    • 2006
  • Dry sliding wear behavior of low carbon dual phase steel, of which microstructure consists of hard martensite in a ductile ferrite matrix, has been investigated. The wear characteristics of the dual phase steel was compared with that of a plain carbon steel which was normalized at $950^{\circ}C$ for 30min and then air-cooled. Dry sliding wear tests were carried out using a pin-on-disk type tester at various loads of 1N to 10N under a constant sliding speed condition of 0.2m/sec against an AISI 52100 bearing steel ball at room temperature. The sliding distance was fixed as 1000m for all wear tests. The wear rate was calculated by dividing the weight loss measured to the accuracy of $10^{-5}g$ by the specific gravity and sliding distance. The worn surfaces and wear debris were analyzed by SEM, EDS and a profilomter. Micro vickers hardness values of the cross section of worn surface were measured to analyze strain hardening behavior underneath the wearing surfaces. The were rate of the dual phase steel was lower than the plain carbon steel. Oxidation on the sliding surface and strain hardening were attributed for the higher wear resistance of the dual phase steel.

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A Study on the Diffusion Behaviors in Weld Interface of Cr-Mo Steel/Austenitic Stainless Steel (Cr-Mo강/오스테나이트계 스테인리스강 용접재의 용접계면에서의 확산거동에 관한 연구)

  • 김동배;이상율;이종훈;이상용;양성철
    • Journal of Welding and Joining
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    • v.17 no.4
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    • pp.46-52
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    • 1999
  • Some of the pressurized reactor pressure vessels used in many chemical plants are made of low alloy carbon steel plates internally clad with an austenitic stainless steel for improved anti-corrosion properties. In this study, metallurgic structure of the weld interface of A 387 Grade12Class1 low alloy carbon steel claded with A182-F321 austenitic stainless steel after thermal exposure simulation heat treatment was investigated to display a characteristic behavior of dissimilar metal weld interface with thermal exposure during service at high temperature and pressure. EPMA, STEM, vickers-hardness test were performed and the results were correlated with the microstructure. To estimate the depth of the carburized/decarburized bands quantitatively, a model for carbon diffusion was proposed. The validity of the proposed theoretical relationships was confirmed by the directly measured data from the welded parts failed during service.

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Inhomogeneity of Hot Rolling Texture in Cu/Nb Added Ultra Low Carbon Steels

  • Jiang, Ying-Hua;Park, Young-Koo;Lee, Oh-Yeon
    • Korean Journal of Materials Research
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    • v.17 no.12
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    • pp.634-636
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    • 2007
  • The texture and microstructure in Cu/Nb added ultra low carbon steels through the different thickness layer were studied after hot rolling. It was found that the two ultra low carbon steels all show the inhomogeneity of hot rolling texture and the Cu-added ultra low carbon steel was far more inhomogeneous than Nb-added one. In the center layer, the strong ${\alpha}\;fibre,\;{\gamma}\;fibre$ textures and the shear textures including 001<110>, 111<112> were founded. Near the surface, the ${\alpha}\;fibre$ texture and the orientation texture caused by a typical plane-strain deformation condition of bcc metals were observed.

Physical/Chemical Characterization of Ordinary Portland Cement/Ground Granulated Blast Furnace Slag Pastes Containing Low Carbon Steel as Reinforcements

  • Hwang, Jin-Ha
    • Korean Journal of Materials Research
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    • v.13 no.2
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    • pp.94-100
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    • 2003
  • The interface between low carbon steel and blended cement pastes containing slag was investigated using impedance spectroscopy. In addition, the pastes were characterized by several analytical methods (XRD, EDX, electrode potential, pH and ICP). The electrical behavior of the interface in the blended slag systems is correlated to its corresponding pore solution chemistry and the products present in the interface. Passivation occurred at the paste/steel interfaces, in cement pastes up to containing from 0 to 75% slag content. 100% slag paste induced corrosion of the low carbon steel, which could be explained by the influence of sulfur on the system.