P R SREENIVASAN | Indira Gandhi Centre for Atomic Research (original) (raw)

Papers by P R SREENIVASAN

Further application of the cleavage fracture stress model for estimating the T 0 of highly embrit... more Further application of the cleavage fracture stress model for estimating the T 0 of highly embrittled ferritic steels The semi-empirical cleavage fracture stress model (CFS), based on the microscopic cleavage fracture stress, r f , for estimating the ASTM E1921 reference temperature (T 0)o f ferritic steels from instrumented impact testing of unpre-cracked Charpy V-notch specimens is further confirmed by test results for additional steels, including steels highly embrittled by thermal aging or irradiation. In addition to the ferrite–pearlite, bainitic or tempered martensitic steels (which was examined earlier), acicular or polygonal ferrite, precipitation-strengthened or additional simulated heat affected zone steels are also evaluated. The upper limit for the applicability of the present CFS model seems to be T 41J *160 to 170 8Co rT 0 or T Qcfs (T 0 estimate from the present CFS model) *100 to 120 8C. This is not a clear-cut boundary, but indicative of an area of caution where generation and evaluation of further data are required. However, the present work demonstrates the applicability of the present CFS model even to substantially embrittled steels. The earlier doubts expressed about T Qcfs becoming unduly non-conservative for highly embrittled steels has not been fully substantiated and partly arises from the necessity of modifications in the T 0 evaluation itself at high degrees of embrittlement suggested in the literature.

Journal of ASTM International, 2012

A recently proposed semi-empirical cleavage fracture stress (CFS) model by the author based on th... more A recently proposed semi-empirical cleavage fracture stress (CFS) model by the author based on the microscopic cleavage fracture stress, σ f , for estimating the ASTM E-1921 reference temperature, T 0 , of ferritic steels from instrumented impact test (IIT) of Charpy V-notch (CVN) specimens without precracking has been demonstrated for steels with room temperature yield strength in the range 400-750 MPa, including irradiated steels. The estimate of T 0 , based on the CFS model, T Qcfs lies within a ± 20 ºC band, being conservative for most of the steels, but less conservative than T QIGC based on the IGC-procedure. CFS model enhances the validity and utility of the CVN IIT by enabling estimation of design-relevant master curve from unprecracked CVN specimens. In this paper, the method is further applied to some steels (both unirradiated and irradiated) reported in the literature most of which have only IIT data and static tensile data available. The method has also been applied to some IIT test results obtained at IGCAR for 9Cr-1Mo steel in various simulated weld-heat affected zone conditions. The results are compared with T QIGC or other estimates like T QBT or T 0 , if available.

A semi-empirical cleavage fracture stress (CFS) model, mainly depending on the CFS, r f , has bee... more A semi-empirical cleavage fracture stress (CFS) model, mainly depending on the CFS, r f , has been derived for estimating the ASTM E1921 reference temperature (T 0 ) and demonstrated for ferritic steels with yield strength in the range 400-750 MPa. This requires only instrumented impact test of CVN specimens without precracking and static yield stress data. The T 0 estimate based on the CFS model, T Qcfs , lies within a 620 C band, being conservative for most of the steels, but less conservative than T QIGC based on the IGCprocedure (see Nomenclature for definition). Applicability and acceptability of the present calibration curves for highly irradiated steels need further examination.

International Journal of Fracture, Jan 1, 2000

International journal of …, Jan 1, 1996

Fatigue & Fracture …, Jan 1, 1996

... 855 Page 2. 856 PR SREENIVASAN et al. u = Poisson's ratio W = specimen width a = ang... more ... 855 Page 2. 856 PR SREENIVASAN et al. u = Poisson's ratio W = specimen width a = angle of rotation of the specimen in the SEM with respect to the electron beam 6 = CTOD Ssl, 6, = elastic and plastic parts of 6 ... Page 4. 858 PR SREENIVASAN et al. ...

Journal of nuclear …, Jan 1, 1996

Dynamic fracture toughness and Charpy impact properties of a normalised and tempered AISI 403 mar... more Dynamic fracture toughness and Charpy impact properties of a normalised and tempered AISI 403 martensitic stainless steel obtained from instrumented impact tests are presented. Procedures for estimating dynamic fracture toughness (K Id ) from the load-time traces obtained in ...

Journal of Nuclear …, Jan 1, 1987

78 Journal of Nuclear Materials 150(1987) 78 -84 North-Holland. Amsterdam EVALUATION OF AGEING-IN... more 78 Journal of Nuclear Materials 150(1987) 78 -84 North-Holland. Amsterdam EVALUATION OF AGEING-INDUCED EMBRITTLEMENT IN AN AUSTENITIC STAINLESS STEEL BY INSTRUMENTED IMPACT TESTING KG SAMUEL, PR SREENIVASAN, SK RAY and P. RODRIGUEZ ...

… Materials Transactions A, Jan 1, 2005

CVN tests, using a modified Schindler procedure to evaluate KJd; the result shows close agreement... more CVN tests, using a modified Schindler procedure to evaluate KJd; the result shows close agreement with that obtained from the PCVN tests. The ASME KIR-curve approach proves to be too conserva-tive compared to the obtained trend of the fracture toughness with temperature. ...

Materials …, Jan 1, 2002

9Cr–1Mo steel in the normalised and tempered condition is used for steam generator structural mat... more 9Cr–1Mo steel in the normalised and tempered condition is used for steam generator structural material in conventional and nuclear power plants. High-temperature creep strength, coupled with adequate corrosion resistance and long-term microstructural stability, has made this ...

International Journal of Fracture, Jan 1, 2000

International journal of …, Jan 1, 2004

International Journal of Fracture 125: 387–403, 2004. © 2004 Kluwer Academic Publishers. Printed ... more International Journal of Fracture 125: 387–403, 2004. © 2004 Kluwer Academic Publishers. Printed in the Netherlands. ... V-notch impact tests using modified Schindler procedure for ... PR SREENIVASAN ∗ , A. MOITRA, SK RAY and SL MANNAN Materials Development Group, Indira Gandhi ...

Transactions of the Indian Institute of Metals(India), Jan 1, 1996

International journal of …, Jan 1, 1993

This paper reports the results of analysis of the load-temperature data obtained from instrumente... more This paper reports the results of analysis of the load-temperature data obtained from instrumented impact tests carried out at various temperatures using half-thick Charpy V-notch specimens of a 3·5% Ni (ASTM A 203D) steel. The material was tested after irradiation and after an ...

International journal of …, Jan 1, 1992

International journal of …, Jan 1, 1996

From instrumented drop-weight tests, the nil ductility transition temperature (T NDT ), and a con... more From instrumented drop-weight tests, the nil ductility transition temperature (T NDT ), and a conservative estimate of dynamic fracture toughness (K Id ), at T NDT for normalised and tempered 9Cr---1Mo steel, are determined to be −25°C and 70 MPa√m, respectively. The latter value agrees ...

Journal of engineering …, Jan 1, 2003

Further application of the cleavage fracture stress model for estimating the T 0 of highly embrit... more Further application of the cleavage fracture stress model for estimating the T 0 of highly embrittled ferritic steels The semi-empirical cleavage fracture stress model (CFS), based on the microscopic cleavage fracture stress, r f , for estimating the ASTM E1921 reference temperature (T 0)o f ferritic steels from instrumented impact testing of unpre-cracked Charpy V-notch specimens is further confirmed by test results for additional steels, including steels highly embrittled by thermal aging or irradiation. In addition to the ferrite–pearlite, bainitic or tempered martensitic steels (which was examined earlier), acicular or polygonal ferrite, precipitation-strengthened or additional simulated heat affected zone steels are also evaluated. The upper limit for the applicability of the present CFS model seems to be T 41J *160 to 170 8Co rT 0 or T Qcfs (T 0 estimate from the present CFS model) *100 to 120 8C. This is not a clear-cut boundary, but indicative of an area of caution where generation and evaluation of further data are required. However, the present work demonstrates the applicability of the present CFS model even to substantially embrittled steels. The earlier doubts expressed about T Qcfs becoming unduly non-conservative for highly embrittled steels has not been fully substantiated and partly arises from the necessity of modifications in the T 0 evaluation itself at high degrees of embrittlement suggested in the literature.

Journal of ASTM International, 2012

A recently proposed semi-empirical cleavage fracture stress (CFS) model by the author based on th... more A recently proposed semi-empirical cleavage fracture stress (CFS) model by the author based on the microscopic cleavage fracture stress, σ f , for estimating the ASTM E-1921 reference temperature, T 0 , of ferritic steels from instrumented impact test (IIT) of Charpy V-notch (CVN) specimens without precracking has been demonstrated for steels with room temperature yield strength in the range 400-750 MPa, including irradiated steels. The estimate of T 0 , based on the CFS model, T Qcfs lies within a ± 20 ºC band, being conservative for most of the steels, but less conservative than T QIGC based on the IGC-procedure. CFS model enhances the validity and utility of the CVN IIT by enabling estimation of design-relevant master curve from unprecracked CVN specimens. In this paper, the method is further applied to some steels (both unirradiated and irradiated) reported in the literature most of which have only IIT data and static tensile data available. The method has also been applied to some IIT test results obtained at IGCAR for 9Cr-1Mo steel in various simulated weld-heat affected zone conditions. The results are compared with T QIGC or other estimates like T QBT or T 0 , if available.

A semi-empirical cleavage fracture stress (CFS) model, mainly depending on the CFS, r f , has bee... more A semi-empirical cleavage fracture stress (CFS) model, mainly depending on the CFS, r f , has been derived for estimating the ASTM E1921 reference temperature (T 0 ) and demonstrated for ferritic steels with yield strength in the range 400-750 MPa. This requires only instrumented impact test of CVN specimens without precracking and static yield stress data. The T 0 estimate based on the CFS model, T Qcfs , lies within a 620 C band, being conservative for most of the steels, but less conservative than T QIGC based on the IGCprocedure (see Nomenclature for definition). Applicability and acceptability of the present calibration curves for highly irradiated steels need further examination.

International Journal of Fracture, Jan 1, 2000

International journal of …, Jan 1, 1996

Fatigue & Fracture …, Jan 1, 1996

... 855 Page 2. 856 PR SREENIVASAN et al. u = Poisson's ratio W = specimen width a = ang... more ... 855 Page 2. 856 PR SREENIVASAN et al. u = Poisson's ratio W = specimen width a = angle of rotation of the specimen in the SEM with respect to the electron beam 6 = CTOD Ssl, 6, = elastic and plastic parts of 6 ... Page 4. 858 PR SREENIVASAN et al. ...

Journal of nuclear …, Jan 1, 1996

Dynamic fracture toughness and Charpy impact properties of a normalised and tempered AISI 403 mar... more Dynamic fracture toughness and Charpy impact properties of a normalised and tempered AISI 403 martensitic stainless steel obtained from instrumented impact tests are presented. Procedures for estimating dynamic fracture toughness (K Id ) from the load-time traces obtained in ...

Journal of Nuclear …, Jan 1, 1987

78 Journal of Nuclear Materials 150(1987) 78 -84 North-Holland. Amsterdam EVALUATION OF AGEING-IN... more 78 Journal of Nuclear Materials 150(1987) 78 -84 North-Holland. Amsterdam EVALUATION OF AGEING-INDUCED EMBRITTLEMENT IN AN AUSTENITIC STAINLESS STEEL BY INSTRUMENTED IMPACT TESTING KG SAMUEL, PR SREENIVASAN, SK RAY and P. RODRIGUEZ ...

… Materials Transactions A, Jan 1, 2005

CVN tests, using a modified Schindler procedure to evaluate KJd; the result shows close agreement... more CVN tests, using a modified Schindler procedure to evaluate KJd; the result shows close agreement with that obtained from the PCVN tests. The ASME KIR-curve approach proves to be too conserva-tive compared to the obtained trend of the fracture toughness with temperature. ...

Materials …, Jan 1, 2002

9Cr–1Mo steel in the normalised and tempered condition is used for steam generator structural mat... more 9Cr–1Mo steel in the normalised and tempered condition is used for steam generator structural material in conventional and nuclear power plants. High-temperature creep strength, coupled with adequate corrosion resistance and long-term microstructural stability, has made this ...

International Journal of Fracture, Jan 1, 2000

International journal of …, Jan 1, 2004

International Journal of Fracture 125: 387–403, 2004. © 2004 Kluwer Academic Publishers. Printed ... more International Journal of Fracture 125: 387–403, 2004. © 2004 Kluwer Academic Publishers. Printed in the Netherlands. ... V-notch impact tests using modified Schindler procedure for ... PR SREENIVASAN ∗ , A. MOITRA, SK RAY and SL MANNAN Materials Development Group, Indira Gandhi ...

Transactions of the Indian Institute of Metals(India), Jan 1, 1996

International journal of …, Jan 1, 1993

This paper reports the results of analysis of the load-temperature data obtained from instrumente... more This paper reports the results of analysis of the load-temperature data obtained from instrumented impact tests carried out at various temperatures using half-thick Charpy V-notch specimens of a 3·5% Ni (ASTM A 203D) steel. The material was tested after irradiation and after an ...

International journal of …, Jan 1, 1992

International journal of …, Jan 1, 1996

From instrumented drop-weight tests, the nil ductility transition temperature (T NDT ), and a con... more From instrumented drop-weight tests, the nil ductility transition temperature (T NDT ), and a conservative estimate of dynamic fracture toughness (K Id ), at T NDT for normalised and tempered 9Cr---1Mo steel, are determined to be −25°C and 70 MPa√m, respectively. The latter value agrees ...

Journal of engineering …, Jan 1, 2003