Use of the DWTT Energy for Predicting Ductile Fracture Behavior in Controlled-Rolled Steel Line Pipes

Wilkowski, G.; Maxey, W.A.; Eiber, R.J.

doi:10.1179/cmq.1980.19.1.59

Cited by 33 publications

(20 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These testing methods have correlated well with the actual fracture propagation behavior of conventional pipeline steels that have a CVN USE below 100 J. [7,8] This correlation has become less obviousness, however, with phenomena such as the rising upper shelf, [9] separation, [10] and abnormal fracture appearance [3] occurring during DWTT, because the toughness of pipeline steels has been greatly improved through manufacturing advancements such as controlled rolling and accelerated cooling. As a way to solve this problem, Chevron notch or static precracked DWTT specimens, the notch of which is adjusted so that the fracture-initiation energy is lower than that of the standard pressed-notch DWTT specimen, are used for testing high-toughness pipeline steels.…”

Section: Introductionmentioning

confidence: 98%

Effects of Mo, Cr, and V Additions on Tensile and Charpy Impact Properties of API X80 Pipeline Steels

Han

Shin

Seo

et al. 2009

Metall Mater Trans A

View full text Add to dashboard Cite

In this study, four API X80 pipeline steels were fabricated by varying Mo, Cr, and V additions, and their microstructures and crystallographic orientations were analyzed to investigate the effects of their alloying compositions on tensile properties and Charpy impact properties. Because additions of Mo and V promoted the formation of fine acicular ferrite (AF) and granular bainite (GB) while prohibiting the formation of coarse GB, they increased the strength and upper-shelf energy (USE) and decreased the energy transition temperature (ETT). The addition of Cr promoted the formation of coarse GB and hard secondary phases, thereby leading to an increased effective grain size, ETT, and strength, and a decreased USE. The addition of V resulted in a higher strength, a higher USE, a smaller effective grain size, and a lower ETT, because it promoted the formation of fine and homogeneous of AF and GB. The steel that contains 0.3 wt pct Mo and 0.06 wt pct V without Cr had the highest USE and the lowest ETT, because its microstructure was composed of fine AF and GB while its maintained excellent tensile properties.

show abstract

Section: Introductionmentioning

confidence: 98%

Effects of Mo, Cr, and V Additions on Tensile and Charpy Impact Properties of API X80 Pipeline Steels

Han

Shin

Seo

et al. 2009

Metall Mater Trans A

View full text Add to dashboard Cite

show abstract

“…[3] Because of the longer crack propagation path in DWTT specimens, DWTT absorbed energy was known to be a more reliable parameter to evaluate the propagation resistance to dynamic ductile fracture (DDF) of line-pipe steels than CVN absorbed energy. [9,10,11] However, there still remain problems including uncertainties in the selection criteria of the notch shape of DWTT specimens. In the case of thick steels of over 19 mm in thickness, the test temperature is indiscriminately lowered after the specimen thickness is reduced to 19 mm, which also leads to uncertainties for reliable evaluation of absorbed energy or transition temperature.…”

Section: Introductionmentioning

confidence: 99%

Effects of Notch Shape and Specimen Thickness on Drop-Weight Tear Test Properties of API X70 and X80 Line-Pipe Steels

Shin

Hwang

Lee

et al. 2007

Metall Mater Trans A

View full text Add to dashboard Cite

In the present study, effects of notch shape and specimen thickness on drop-weight tear test (DWTT) properties of API X70 and X80 line-pipe steels fabricated by varying hot-rolling conditions were investigated. The DWTT was conducted on the rolled steels, and the results were discussed in comparison with the Charpy V-notch (CVN) impact test and crack-tip opening angle (CTOA) test data. The DWTT results indicated that the steels rolled in the singlephase region had the higher upper shelf energy (USE) than the steel rolled in the two-phase region, because their microstructures were composed of acicular ferrite (AF). The DWTT energy transition temperature (ETT) of the steel rolled in the two-phase region was the lowest, because it had a finer effective grain size and the lowest volume fraction of hard secondary phases. Chevron notch (CN) DWTT energy density did not increase much with increasing specimen thickness, whereas pressed notch (PN) DWTT energy density increased by 1 to 3 J/ mm 2 , because the total energy of the CN DWTT increased less than that of the PN DWTT due to the larger stress concentration at the CN. The ETT increased with increasing specimen thickness due to the increase in constraint state, and the ETT of the CN DWTT was slightly lower than that of PN DWTT. The measured CTOA showed better correlation with the DWTT propagation energy than with the CVN or DWTT total energy because it was related to the crack propagation speed. The value of sin (2CTOA) reliably showed a linearly proportional relation with the DWTT propagation energy density.

show abstract

“…O Drop Weight Tear Test (DWTT) é um método de avaliação da tenacidade empregado para assegurar que o aço usado na fabricação de tubos não esteja sujeito à propagação de fratura frágil quando em serviço, ou seja, caso ocorra uma fratura à temperatura mínima de operação, ela se propagará de modo dúctil [1]. No entanto, tem sido verificado que aços modernos para dutos, produzidos via laminação controlada seguida de resfriamento acelerado, que exibem elevadas resistência mecânica e tenacidade em ensaios de impacto Charpy (entre 200 e 350 J no patamar superior) e, especialmente, espessuras acima de 25 mm, podem não apresentar o mesmo comportamento à fratura que os aços convencionais, quando submetidos ao DWTT [2][3][4].…”

Section: Introductionunclassified

Avaliação Da Tenacidade De Aço De Elevada Resistência Mecânica Por Ensaio De DWTT

Faria¹,

Santos²,

Alé³

et al. 2018

ABM Proceedings

View full text Add to dashboard Cite

ResumoO Drop Weight Tear Test (DWTT) é comumente empregado para avaliar a capacidade de um material impedir a propagação de fratura frágil na temperatura de projeto. Esse ensaio quando aplicado a aços modernos de elevada tenacidade, produzidos via resfriamento acelerado, para aplicação em dutos, pode não exibir o mesmo comportamento à fratura dos aços convencionais, por apresentar um tipo de fratura anormal, denominada fratura inversa. Esse tipo de fratura, por sua vez, invalida os resultados de DWTT segundo os critérios estabelecidos pela API RP 5L3. Neste trabalho, são apresentados os resultados obtidos em ensaio de DWTT, utilizando corpos de prova full-size e sub-size, de um aço de elevada tenacidade, produzido com distintas condições de processamento termomecânicas evidenciando o fenômeno de fratura inversa. De uma forma geral, observou-se uma correlação entre os resultados de DWTT e as propriedades mecânicas em tração. Os testes também apontaram que a geometria do corpo-de-prova (full-size ou sub-size) possui uma influência direta no resultado do ensaio de DWTT. Palavras-chave: DWTT; Fratura inversa; Aço de elevada tenacidade; API RP 5L3 EVALUATION OF TOUGHNESS IN PLATES STEEL OF HIGH STRENGTH BYDWTT TESTING Abstract Drop Weight Tear Test (DWTT) is commonly used to determine the material ability to arrest brittle fracture at the design temperature. Modern steels with high toughness, produced by accelerated cooling for applications in linepipes not always exhibit the same fracture behavior of conventional steels when submitted to this test. However, this fracture type invalidates the results of DWTT according to criteria established by API RP 5L3. In the present study, DWTT in full-size and a sub-size specimens were conducted on a high toughness steel, produced with different thermomechanical processing conditions, and the inverse fracture occurring in the hammer-impacted region was evaluated. In a general manner, a correlation between DWTT results and tensile mechanical properties was observed. The tests also show that the geometry of the specimen (full-size or sub-size) has a direct influence on DWTT results.

show abstract

Use of the DWTT Energy for Predicting Ductile Fracture Behavior in Controlled-Rolled Steel Line Pipes

Cited by 33 publications

References 1 publication

Effects of Mo, Cr, and V Additions on Tensile and Charpy Impact Properties of API X80 Pipeline Steels

Effects of Mo, Cr, and V Additions on Tensile and Charpy Impact Properties of API X80 Pipeline Steels

Effects of Notch Shape and Specimen Thickness on Drop-Weight Tear Test Properties of API X70 and X80 Line-Pipe Steels

Avaliação Da Tenacidade De Aço De Elevada Resistência Mecânica Por Ensaio De DWTT

Contact Info

Product

Resources

About