Intergranular failure in steel: the role of grain-boundary composition

Briant, C. L.; Banerji, Samir K.

doi:10.1179/095066078790136652

Cited by 124 publications

(36 citation statements)

References 18 publications

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“…32) A solute causes embrittlement by reducing the cohesion across the boundary plane. On the other hand, those solutes which enhance covalent bonding normal to the boundary must reduce embrittlement.…”

Section: Avoiding Grain Boundary Embrittlementmentioning

confidence: 99%

Advances in Physical Metallurgy and Processing of Steels. Design of Ferritic Creep-resistant Steels.

Bhadeshia

2001

ISIJ International

202

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Creep resistant steels must be reliable over very long periods of time in severe environments. Their microstructures have to be very stable, both in the wrought and in the welded states. This paper reviews the quantitative methods for the design of steels for elevated temperature applications. A methodology is described for the calculation of complex precipitation reactions over periods extending many tens of years. However, microstructure alone is not enough in the design of alloys. The estimation of the creep rupture stress using a neural network technique is described in the second part of this review. The calculation of the influence of solute-elements on the self-diffusivity of iron, which features in many creep equations, is an emerging area in alloy design. The methodology for such calculations is reviewed in the final section of the paper.KEY WORDS: creep strength; power plant; carbides; martensite; bainite.

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Section: Avoiding Grain Boundary Embrittlementmentioning

confidence: 99%

Advances in Physical Metallurgy and Processing of Steels. Design of Ferritic Creep-resistant Steels.

Bhadeshia

2001

ISIJ International

202

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“…Quenching and tempering are well-established means to strengthen these steels, which are achieved mainly due to precipitation of fine alloy carbides during tempering. 3,4) The highest strength level in alloy steels of this type can be obtained by martensite structure in untempered condition; this structure, however, is rarely used in direct applications due to its associated high internal stresses developed during the martensitic transformation, which severely impairs ductility and toughness of the material. [5][6][7] The process of tempering is able to considerably reduce these stresses without changing the basic features of the martensitic structure.…”

Section: Introductionmentioning

confidence: 99%

“…Numerous investigations have been carried out to understand the effect of microstructure on the temper embrittlement phenomena. 1,3,5,8) There exists a series of attempts to detect the temper embrittlement regime of these alloy steels using variation of impact toughness with tempering temperature. 1,3,5) Current design concepts necessitate database on fracture toughness for this engineering components, however, literature related to temper embrittlement phenomenon with respect to the variation of fracture toughness with tempering temperature do not exist to the best knowledge of the authors.…”

Section: Introductionmentioning

confidence: 99%

Effect of Tempering on Mechanical Properties of V-added AISI 4335 Steel

2010

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“…17) It is generally believed that the impurities segregate to the prior austenite grain boundaries, reduce their cohesive strength and, hence, cause intergranular fracture along the prior austenite grain boundaries. 12,18,19) Also, a few other studies have reported that precipitation of carbides (Fe 3 C) on the ferrite grain boundaries results in a transient build-up of impurities at the ferrite/carbide interfaces and, hence, causes intergranular fracture along the ferrite grain boundaries. [20][21][22] Although it is known that the presence of impurities in a segregated state is essential to cause TE, the exact mechanism of TE is still not clearly understood.…”

Section: Introductionmentioning

confidence: 99%

“…are responsible for causing temper embrittlement (TE) in steels. [12][13][14][15][16] The TE is manifested by a decrease in the notched-bar fracture energy 15) or by an increase in the ductile-brittle transition temperature. 17) It is generally believed that the impurities segregate to the prior austenite grain boundaries, reduce their cohesive strength and, hence, cause intergranular fracture along the prior austenite grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

The Segregation Behavior of Phosphorus in Ti and Ti+Nb Stabilized Interstitial-Free Steels.

et al. 2000

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The phenomenon of cold work embrittlement (CWE) in the P-added high strength interstitial-free steels has been associated with the segregation of P to the ferrite grain boundaries. This segregation by P is believed to decrease the cohesive strength of the grain boundaries by weakening their bonding. Hence, the resistance of the steel to brittle fracture, i.e., intergranular fracture, is greatly decreased. The goal of the present study was to investigate the segregation behavior of P during the different stages of processing (prior to and after coiling, and after cold rolling and annealing) in Ti and Ti+Nb stabilized interstitial-free steels. It was found that a considerable amount of segregation of P to the ferrite grain boundaries occurred during the coiling process in Ti-stabilized interstitial-free steels. However, with the addition of Nb in the Ti+Nb-stabilized interstitial-free steels, the segregation of P was decreased in the as-coiled condition. The P content on the ferrite grain boundaries in the final cold rolled and annealed condition was found to depend on two factors; (1) the segregation of P in the as-coiled condition, and (2) availability of Ti to form phosphides during the annealing process. It was confirmed in this study that the addition of P decreases the CWE resistance of the steel. Furthermore, it appears that the CWE resistance of the TiϩNb-stabilized interstitial-free steels is improved by the presence of solute Nb on the ferrite grain boundaries.KEY WORDS: segregation; ULC Steels; cold work embrittlement; thermomechanical processing.is essential to cause TE, the exact mechanism of TE is still not clearly understood.The phenomenon of temper embrittlement in ULC steels has been also documented and is called secondary work (SWE) or cold work (CWE) embrittlement. [23][24][25][26][27][28][29][30] The CWE phenomenon is defined as the susceptibility of the sheet material to intergranular fracture during the secondary working of a deeply drawn part or while in service. The CWE phenomenon is attributed to the segregation of P to the ferrite grain boundaries which is believed to reduce their cohesive strength and, hence, cause intergranular fracture along the ferrite grain boundaries. 23,29,30) It has been shown that the Nb-containing steels have a better CWE resistance than the Ti-containing steels. 24,31) This has been attributed to the partial stabilization of C in the Nb-containing steels. It is believed that carbon increases the grain boundary cohesion and increases the CWE resistance. [32][33][34] Furthermore, Erhart and Grabke have shown that as the C concentration on the grain boundaries is increased, the concentration of P on the grain boundaries is decreased which would also improve the CWE resistance. 35) Although it is known that the segregation of P to the ferrite grain boundaries causes CWE, its segregation behavior during the different stages of thermomechanical processing of interstitial-free steels is not known. In this study, the segregation behavior of P during the different stage...

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Intergranular failure in steel: the role of grain-boundary composition

Cited by 124 publications

References 18 publications

Advances in Physical Metallurgy and Processing of Steels. Design of Ferritic Creep-resistant Steels.

Advances in Physical Metallurgy and Processing of Steels. Design of Ferritic Creep-resistant Steels.

Effect of Tempering on Mechanical Properties of V-added AISI 4335 Steel

The Segregation Behavior of Phosphorus in Ti and Ti+Nb Stabilized Interstitial-Free Steels.

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