Application of a local approach to ductile-brittle transition in a low-alloyed steel

Amar, Elmahdi; Pineau, A.

doi:10.1016/0029-5493(87)90233-0

Cited by 19 publications

(3 citation statements)

References 6 publications

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“…Fig. 9b shows that this simplified approach applied to A 508 RPV steel (Amar and Pineau 1987) As already stated, this simplified approach involves strong limitations since it does not account for the modifications in the stress field ahead of a propagating crack and does not account for a possible change in the nature of cleavage initiating sites during crack propagation. Further detailed discussion on the applicability of this simplified approach can be found elsewhere (Pineau and Pardoen, 2007).…”

Section: A Simplified Approachmentioning

confidence: 97%

Modeling ductile to brittle fracture transition in steels—micromechanical and physical challenges

Pineau

2008

Int J Fract

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Both scientists and engineers are very much concerned with the study of ductileto-brittle transition (DBT) in ferritic steels. For historical reasons the Charpy impact test remains widely used in the industry as a quality control tool to determine the DBT temperature. The transition between the two failure modes, i.e. brittle cleavage at low temperature and ductile fracture at the upper shelf occurs also at low loading rate in fracture toughness tests. Recent developments have been made in the understanding of the micromechanisms controlling either cleavage fracture in BCC metals or ductile rupture by cavity nucleation, growth and coalescence. Other developments have also been made in numerical tools such as the finite element (FE) method incorporating sophisticated constitutive equations and damage laws to simulate ductile crack growth (DCG) and cleavage fracture. Both types of development have thus largely contributed to modeling DBT occurring either in impact tests or in fracture toughness tests. This constitutes the basis of a modern methodology to investigate fracture, which is the so-called local approach to fracture. In this study the micromechanisms of brittle cleavage fracture and ductile rupture are firstly shortly reviewed. Then the transition between both modes of failure is investigated. It is shown that the DBT behavior observed in impact tests or in fracture toughness specimens can be reasonably well predicted using modern theories on brittle and ductile fracture in conjunction with FE numerical simulations. The review includes a detailed study of a number of metallurgical parameters contributing to the variation of the DBT temperature. Two main types of steels are considered : (i) quenched and tempered bainitic and martensitic steels used in the fabrication of pressurized water reactors, and (ii) modern high-toughness line-pipe steels obtained by chemical variations and optimized hot-rolling conditions. An attempt is also made to underline the research areas which remain to be explored for improving the strength-toughness compromise in the development of steels.

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Section: A Simplified Approachmentioning

confidence: 97%

Modeling ductile to brittle fracture transition in steels—micromechanical and physical challenges

Pineau

2008

Int J Fract

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“…Substantial research efforts over the last few decades have developed statistical treatments of cleavage fracture based both on macroscopic approaches and on local approaches . The master curve approach has evolved into a standard procedure in characterizing the temperature dependence of the macroscopic fracture toughness over the DBT regime.…”

Section: Introductionmentioning

confidence: 99%

“…Substantial research efforts over the last few decades have developed statistical treatments of cleavage fracture based both on macroscopic approaches [11][12][13][14][15] and on local approaches. [16][17][18][19] The master curve approach 7,12,14 has evolved into a standard procedure 20 in characterizing the temperature dependence of the macroscopic fracture toughness over the DBT regime. American Society of Testing and Materials (ASTM) E-1921 20 prescribes the protocol to measure the reference temperature T 0 required by the master curve to quantify the median fracture toughness (K Jc, median ) over the DBT region.…”

Section: Introductionmentioning

confidence: 99%

A K₀‐based calibration procedure for the Weibull stress cleavage model

Qian

Chen

2013

Fatigue Fract Eng Mat Struct

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This paper presents a simplified calibration procedure for the microscopic Weibull stress model to estimate the cumulative probability of cleavage fracture for ferritic steels. The proposed method requires two discrete values of the macroscopic Weibull scale parameter (K0) in contrast to the two sets of statistically significant fracture toughness data mandated in previous calibration schemes. The proposed approach predicates on the fundamental assumption that the macroscopic toughness, for specimens dominated by cleavage mechanisms, follow the three‐parameter Weibull model outlined in the testing standards. The calibration procedure thus generates two sets of fictitious toughness data corresponding to two sets of specimens with marked differences in crack‐front constraints. The calibrated Weibull parameters agree closely with the calibration results based on the conventional approach for the Euro steels. The proposed calibration also leads to an improved method to determine a limiting load level, beyond which extensive plastic deformation propagates in the specimen.

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Global and Local Approaches of Fracture — Transferability of Laboratory Test Results to Components

Pineau¹

1992

Topics in Fracture and Fatigue

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Application of a local approach to ductile-brittle transition in a low-alloyed steel

Cited by 19 publications

References 6 publications

Modeling ductile to brittle fracture transition in steels—micromechanical and physical challenges

Modeling ductile to brittle fracture transition in steels—micromechanical and physical challenges

A K₀‐based calibration procedure for the Weibull stress cleavage model

Global and Local Approaches of Fracture — Transferability of Laboratory Test Results to Components

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Application of a local approach to ductile-brittle transition in a low-alloyed steel

Cited by 19 publications

References 6 publications

Modeling ductile to brittle fracture transition in steels—micromechanical and physical challenges

Modeling ductile to brittle fracture transition in steels—micromechanical and physical challenges

A K0‐based calibration procedure for the Weibull stress cleavage model

Global and Local Approaches of Fracture — Transferability of Laboratory Test Results to Components

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A K₀‐based calibration procedure for the Weibull stress cleavage model