• Title, Summary, Keyword: Ball Indentation Method

Search Result 17, Processing Time 0.058 seconds

Evaluation of Material Degradation of 1Cr-1Mo-0.25V steel using Ball Indentation Method

  • Seok, Chang-Sung;Kim, Jeong-Pyo;Koo, Jae-Mean
    • Journal of Mechanical Science and Technology
    • /
    • v.18 no.10
    • /
    • pp.1730-1737
    • /
    • 2004
  • The BI (Ball Indentation) method has the potential to assess the mechanical properties and to replace conventional fracture tests. In this study, the effect of aging on mechanical behavior of 1Cr-1Mo-0.25V steels procured by isothermal aging heat-treatment at four different aging times in the range of 0~1820 hours at 630$^{\circ}C$, were investigated using BI system.

A Study on the Evaluation Method of Mechanical Properties by Ball Indentation Method (압입법을 이용한 재료 물성치 평가 기법에 관한 연구)

  • Seok, Chang-Seong;Kim, Jeong-Pyo;Song, Seong-Jin;Kim, Hun-Mo;Kim, Jae-Won;Kim, Su-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.25 no.12
    • /
    • pp.1903-1910
    • /
    • 2001
  • The BI(Ball Indentation) method has a potential to assess the mechanical properties and to replace conventional fracture tests. In this study, the BI test system has been developed to evaluate material properties. Tensile tests, fracture toughness tests, hardness tests and BI tests were performed by the system using four classes of thermally aged specimens. The results of the BI tests were in good agreement with fracture characteristics from a standard fracture test method.

A study on the Evaluation of Material Degradation of 1Cr-1Mo-0.25V Steel using Ball Indentation Method (압입법을 이용한 1Cr-1Mo-0.25V강의 열화도 평가에 관한 연구)

  • Seok, Chang-Sung;Kim, Jeong-Pyo;Ahn, Ha-Neul
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.18 no.4
    • /
    • pp.151-159
    • /
    • 2001
  • As huge energy transfer systems like a nuclear power plant, steam power plant and petrochemical plant are operated for a long time, mechanical properties are changed by degradation. The life time of the systems can be affected by the mechanical properties. BI(Ball Indentation) test has a potential to replace conventional fracture tests like a uniaxial tensile test, fracture toughness test, hardness test and so on. In this paper, we would like to present the ageing evaluation technique by the BI method. The four classes of the thermally aged 1Cr-!mo-0.25V specimens were prepared using an artificially accelerated aging method. Tensile tests, fracture toughness tests, hardness tests and BI tests were performed. The results of the BI tests were in good agreement with fracture characteristics by a standard fracture test method within 5%. The IDE(Indentation Deformation Energy) of a BI technique as a new parameter for evaluating a degradation was suggested and the new IDE parameter clearly depicts the degradation degree.

  • PDF

Estimation of Fracture Toughness of Reactor Pressure Vessel Steels Using Automated Ball Indentation Test

  • Byun, Thak-Sang;Kim, Joo-Hark;Lee, Bong-Sang;Yoon, Ji-Hyun;Hong, Jun-Hwa
    • Proceedings of the Korean Nuclear Society Conference
    • /
    • /
    • pp.129-136
    • /
    • 1997
  • The automated ball indentation(ABI) test was utilized to develop a semi-nondestructive method for estimating the fracture toughness( $K_{JC}$ ) in the transition temperature range. The key concept of the method is that the indentation deformation energy to the load at which the mean ball-specimen contact pressure reaches the fracture stress is related to the fracture energy of the material. ABI tests were performed for the reactor pressure vessel(RPV) base and weld metals at the temperatures of-15$0^{\circ}C$~$0^{\circ}C$ and the fracture toughness (estimated $K_{JC}$ ) was calculated from the indentation load-depth data. For all steels the temperature dependence of the estimated fracture toughness was almost the same as that ASTM $K_{JC}$ master curve The reference temperatures( $T_{o}$)of the steels were determined form the estimated $K_{JC}$ versus temperature curves. The reference temperature was well correlated with the index temperature of 41J Charpy impact energy( $T_{41J}$).).).

  • PDF

A Study on the Evaluation of Material Degradation using Ball Indentation Method (압입법을 이용한 재료 열화의 평가에 관한 연구)

  • Kim, Jeong-Pyo;Seok, Chang-Sung;Ahn, Ha-Neul
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.171-176
    • /
    • 2000
  • As huge energy transfer systems like a nuclear power plant, steam power plant and petrochemical plant are operated for a long time, mechanical properties are changed by degradation. The life time of the systems can be affected by the mechanical properties. BI(Ball Indentation) test has a potential to replace conventional fracture tests like a uniaxial tensile test, fracture toughness test, hardness test and so on. In this paper, we would like to present the aging evaluation technique by the BI method. The four classes of the thermally aged 1Cr-1Mo-0.25V specimens were prepared using an artificially accelerated aging method. Tensile tests, fracture toughness tests, hardness tests and BI tests were performed. The results of the BI tests were in good agreement with fracture characteristics by a standard fracture test method. The IDE(Indentation Deformation Energy) of a BI technique as a new parameter for evaluating a degradation was suggested and the new IDE parameter clearly depicts the degradation degree.

  • PDF

Simulation of Ball Indentation Process by Elasto-Plastic Contact Analysis (탄소성 접촉 해석법을 이용한 볼 압입시험의 시뮬레이션)

  • 이병채;곽병만
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.12 no.2
    • /
    • pp.185-192
    • /
    • 1988
  • Computation of the elasto-plastic solution of ball indentation was carried out by the quadratic programming method. The problem was formulated as an elasto-plastic contact problem under the assumption of small displacement and small deformation and then transformed into a minimization problem. Finite element approximation resulted in a quadratic programming problem. Numerical and experimental study were done with aluminium Al 2024-T351 and commercially pure copper. The computed load-displacement curves were in good agrement with those obtained from experiments. Tabor's relationship for representative strains was also examined. Stress distributions were found to resemble closely those results available in the literature.

Evaluation of Degraded Materials by Automated Ball Indentation(ABI) Technique (압입법을 이용한 재료의 열화도 평가)

  • 김석민;석창성;이승석;권재도
    • Journal of the Korean Society of Safety
    • /
    • v.15 no.1
    • /
    • pp.28-35
    • /
    • 2000
  • As huge energy transfer systems like a nuclear power plant, steam power plant and petrochemical plant are operated for a long time, mechanical properties are changed by degradation. The life time of the systems can be affected by the mechanical properties. So determination of the integrity of the metallic structure is required either to en4sure that failure will not occur during the service life of the components or to evaluate the lifetime extension of the structure. An automated ball indentation(ABI) method was developed as a non-destructive technique for evaluating the integrity of such metallic components. In this paper, we would like to present the aging evaluation technique by the ABI method. The five classes of the thermally aged CF8M specimens were prepared using an artificially accelerated aging method. After holding 100, 300, 900, 1800 and 3600 hours at 43$0^{\circ}C$, the specimens were cooled down using water to room temperature respectively. The tensile test, hardness test, charpy impact test, ABI test were performed. The results of the fracture test were compared with those of ABI test and the new evaluation technique of the integrity of metallic structures was developed.

  • PDF

Prediction of Density Distribution in Sintered Metal Powder Compacts by Indentation Force Equation (압흔하중식에 의한 금속소결분말체내에서의 밀도분포 예측)

  • 박종진
    • Journal of Korean Powder Metallurgy Institute
    • /
    • v.4 no.3
    • /
    • pp.188-195
    • /
    • 1997
  • In most of sintered metal powder compacts, the sintered density distribution is controlled to be as high and uniform as possible to ensure the required mechanical properties. In general, the density distribution in the compacts is not uniform and not easy to measure. In the present study, a method for measuring the density distribution was developed, based on the indentation force equation by which the hardness and the relative density were related. The indentation force equation, expressed as a function of strength constant, workhardening coefficient and relative density, was obtained by finite element analysis of rigid-ball indentation on sintered powder metal compacts. The present method was verified by comparing the predicted density distribution in the sintered Fe-0.5%C-2%Cu compacts with that obtained by experiments, in which the density distribution was directly measured by machining the compacts from the outer surface progressively.

  • PDF

Relationship between Hardness and Relative Ddensity in Sintered Metal Powder Compacts (금속분발소결체의 경도와 상대밀도 관계)

  • 박종진
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • /
    • pp.168-174
    • /
    • 1998
  • In the present study, a method for measuring the relative density by the hardness measurement was proposed for sintered metal powder compacts. It is based on the indentation force equation, by which the relative density is related with the hardness, that was obtained by the finite element analysis of rigid-ball indentation on sintered metal powder compacts. For verifying the method, it was applied to prediction of density distributions in sintered and sintered-and-forged Fe-0.5%C-2%Cu powder compacts.

  • PDF

Residual Stress Analysis of AISI 304 Surface Welding Plate by 3D Finite Element Method (3 차원 유한요소법을 이용한 AISI 304 표면용접평판의 잔류응력해석)

  • Lee, Kyoung-Soo;Kim, Tae-Ryong;Kim, Maan-Won;Park, Jai-Hak
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.390-395
    • /
    • 2008
  • This study is performed to understand three dimensional characteristics of weld residual stress for the surface weld on the stainless steel plate. AISI 304 plate with one path weld on the surface was used as a test specimen. Finite element analysis was done to analyze thermal transient and residual stress due to weld. The result of finite element analysis was validated by previous paper and measurement data. Among various techniques for residual stress measurement, instrumented ball indentation method was applied. The calculated residual stresses by finite element analysis showed good agreement with the measured results.

  • PDF