• Title/Summary/Keyword: hardening time

Search Result 461, Processing Time 0.032 seconds

Estimation of hardening depth using neural network in LASER surface hardening process (레이저 표면경화공정에서 신경회로망을 이용한 경화층깊이의 측정)

  • 박영준;우현구;조형석;한유희
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1993.10a
    • /
    • pp.212-217
    • /
    • 1993
  • In this paper, the hardening depth in Laser surface hardening process is estimated using a multilayered neural network. Input data of the neural network are surface temperature of five points, power and travelling speed of Laser beam. A FDM(finite difference method) is used for modeling the Laser surface hardening process. This model is used to obtain the network's training data sample and to evaluate the performance of the neural network estimator. The simulational results showed that the proposed scheme can be used to estimate the hardening depth on real time.

  • PDF

TSC Properties of Epoxy Composites due to Hardening Time (경화 시간에 따른 에폭시 복합체의 TSC특성)

  • 장인범;신철기;정일현;박건호;이준웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1995.05a
    • /
    • pp.212-215
    • /
    • 1995
  • The thermally stimulated currents (TSC) are measured to know the behaviour of charging particles of epoxy composites at the temperatures range -160~200[$^{\circ}C$] and to prove the various aspects due to hardening time in this study. It is composites at the narrower the magnititude of peak is and hardening time is a degradation from this.

  • PDF

Low Temperature Plastic Hardening Constitutive Equation for Steels of Polar Class Vessels (빙해선박 강재의 저온 소성경화 구성방정식)

  • Min, Dug-Ki;Heo, Young-Mi;Cho, Sang-Rai
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.49 no.3
    • /
    • pp.227-231
    • /
    • 2012
  • In this study, a plastic hardening constitutive equation for steels of polar class vessels at low temperature is proposed. The equation was derived using the experimental data obtained from tensile tests at room and low temperatures. Tensile tests at low temperature are both costly and time consuming because an expensive cold chamber is necessary and it takes too much time to cool down a specimen to set temperature. Using the proposed plastic hardening constitutive equation the plastic hardening characteristics of steels for polar class vessels at low temperature can be easily predicted from the tensile test results at room temperature.

Rheological Properties of Super Early Hardening Cement Paste Using Set Controlling Agent (응결조절제를 첨가한 초속경 시멘트 페이스트의 유동 특성)

  • Yang Seung-Kyu;Um Tai-Sun;Lee Jong-Ryul
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2005.05b
    • /
    • pp.413-416
    • /
    • 2005
  • The super early hardening cement is widely used for reducing construction period. But there are some problems with handling the cement because the loss of workability is so big to control. In this study, the fluidity properties of super early hardening cement paste was evaluated at early age of hydration by using gel-time determination method. 4 types of set controlling agent were selected and combinations of them were used for gel-time test. As a result, the gel-time of super early hardening cement paste was extended up to 20 minutes by using the combinations of several types set controlling agent.

  • PDF

Investigation on surface hardening and corrosion characteristic by water cavitation peening with time for Al 5052-O alloy (5052-O 알루미늄 합금의 워터 캐비테이션 피닝 시간에 따른 표면 경화와 부식 특성에 관한 연구)

  • Kim, Seong-Jong;Hyun, Koang-Yong
    • Corrosion Science and Technology
    • /
    • v.11 no.4
    • /
    • pp.151-156
    • /
    • 2012
  • The cavity formed by the ultrasonic generation in the fluid with the application of water cavitation peening collides into the metal surface. At this time, the surface modification effect such as the work hardening presents by the compressive residual stress formed due to the localized plastic deformation. In this investigation, the water cavitation peening technology in the distilled water with the lapse of time was applied to 5052-O aluminum alloy for aluminum ship of a high value. So, the optimum water cavitation peening time on the effect for surface hardening and anti-corrosion property was investigated. Consequently, the water cavitatin peening time on excellent hardness and corrosion resistance characteristic presented 3.5 min. and 5.0 min, respectively. The surface hardness in the optimum water cavitation peening time was improved approximately 45% compared to the non-WCPed condition. In addition, corrosion current density was decreased.

On the Role of Kinematic Hardening Rules in Predicting Relaxation Behavior (응력이완 거동의 예측에 대한 이동경화법칙의 역할)

  • Ho, Kwang-Soo
    • Transactions of Materials Processing
    • /
    • v.17 no.8
    • /
    • pp.579-585
    • /
    • 2008
  • Numerous experimental investigations on metallic materials and solid polymers have shown that relaxation behavior is nonlinearly dependent on prior strain rate. The stress drops in a constant time interval nonlinearly increase with an increase of prior strain rate. And the relaxed stress associated with the fastest prior strain rate has the smallest stress magnitude at the end of relaxation periods. This paper deals with the performance of three classes of unified constitutive models in predicting the characteristic behaviors of relaxation. The three classes of models are categorized by a rate sensitivity of kinematic hardening rule. The first class uses rate-independent kinematic hardening rule that includes the competing effect of strain hardening and dynamic recovery. In the second class, a stress rate term is incorporated into the rate-independent kinematic hardening rule. The final one uses a rate-dependent format of kinematic hardening rule.

Time-Dependent Spring-back Prediction of Aluminum Alloy 6022-T4 Sheets Using Time-Dependent Constitutive law (시간 의존성 구성방정식을 이용한 AA6022-T4 판재의 탄성 복원 예측)

  • Park, T.;Ryou, H.;Lee, M.G.;Chung, K.H.;Wagoners, R.H.;Chung, K.
    • Transactions of Materials Processing
    • /
    • v.18 no.6
    • /
    • pp.494-499
    • /
    • 2009
  • The time-dependent constitutive law was utilized based on viscoelastic-plasticity to predict the time-dependent spring-back behavior of aluminum alloy 6022-T4 sheets. Besides nonlinear viscoelasticity, non-quadratic anisotropic yield function, Yld2000-2d, was used to account for the anisotropic yield behavior, while the combined isotropic-kinematic hardening law was used to represent the Bauschinger effect and transient hardening. For verification purposes, finite element simulations were performed for the draw-bending and the results were compared with experimental results.

Time-Dependent Spring-back Prediction of Aluminum Alloy 6022-T4 Sheets Using Time-Dependent Constitutive law (시간 의존성 구성방정식을 이용한 AA6022-T4 판재의 탄성 복원 예측)

  • Park, T.;Ryou, R.;Lee, M.G.;Chung, K.H.;Wagoner, R.H.;Chung, K.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2009.05a
    • /
    • pp.330-333
    • /
    • 2009
  • The time-dependent constitutive law was developed based on viscoelastic-plasticity to describe the time-dependent spring-back behavior of aluminum alloy 6022-T4 sheets. Besides nonlinear viscoelasticity, non-quadratic anisotropic yield function, Yld2000-2d, was used to account for the anisotropic yield behavior, while the combined isotropic-kinematic hardening law was used to represent the Bauschinger effect and transient hardening. For verification purposes, finite element simulations were performed for the draw-bending and the results were compared with experimental results.

  • PDF

Multiscale Modeling of Radiation Damage: Radiation Hardening of Pressure Vessel Steel

  • Kwon Junhyun;Kwon Sang Chul;Hong Jun-Hwa
    • Nuclear Engineering and Technology
    • /
    • v.36 no.3
    • /
    • pp.229-236
    • /
    • 2004
  • Radiation hardening is a multiscale phenomenon involving various processes over a wide range of time and length. We present a multiscale model for estimating the amount of radiation hardening in pressure vessel steel in the environment of a light water reactor. The model comprises two main parts: molecular dynamics (MD) simulation and a point defect cluster (PDC) model. The MD simulation was used to investigate the primary damage caused by displacement cascades. The PDC model mathematically formulates interactions between point defects and their clusters, which explains the evolution of microstructures. We then used a dislocation barrier model to calculate the hardening due to the PDCs. The key input for this multiscale model is a neutron spectrum at the inner surface of reactor pressure vessel steel of the Younggwang Nuclear Power Plant No.5. A combined calculation from the MD simulation and the PDC model provides a convenient tool for estimating the amount of radiation hardening.

Development of early strength type hardening Agent for Surface Soil Stabilization Method (연약지반 표층혼합처리를 위한 조기강도 발현형 고화재의 개발)

  • Ki, Tae-Kyoung;Kim, Ki-Hoon;Lee, Byung-Ki;Kwon, O-Bong;Kim, Kyoung-Min;Park, Sang-Joon
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2013.11a
    • /
    • pp.80-81
    • /
    • 2013
  • There is the increasing number of constructing soil or structure on the soft ground during public works. Usually cement or slag cement has been the traditional material for surface soil stabilization method. Recently, early strength development properties of hardening agent is required for driving abilities of execution equipment and shortening of the construction time. Therefore, the purpose of this study is to develop the early compressive strength hardening agent for surface soil stabilization. The study was confirmed performance and availability of hardening agent using early strength type cement and industrial by-product minerals through early strength development properties in accordance with water cement ratio, content of hardening agent for soft soil.

  • PDF