0
Research Papers: Materials and Fabrication

Application of Weibull Stress Criterion to Brittle Fracture Assessment of Heat-Affected Zone-Notched Welds With Residual Stress

[+] Author and Article Information
Yusuke Seko

Tokyo Gas Co., Ltd.,
Yokohama, Japan
e-mail: y.seko@tokyo-gas.co.jp

Yasuhito Imai

Tokyo Gas Co., Ltd.,
Yokohama, Japan
e-mail: yasu-imai@tokyo-gas.co.jp

Masaki Mitsuya

Tokyo Gas Co., Ltd.,
Tokyo, Japan
e-mail: mitsuya@tokyo-gas.co.jp

Noritake Oguchi

Tokyo Gas Co., Ltd.,
Tokyo, Japan
e-mail: yuri-o@tokyo-gas.co.jp

Fumiyoshi Minami

Osaka University,
Osaka, Japan
e-mail: minami@mapse.eng.osaka-u.ac.jp

Contributed by the Pressure Vessel and Piping Division of ASME for publication in the JOURNAL OF PRESSURE VESSEL TECHNOLOGY. Manuscript received April 8, 2015; final manuscript received September 15, 2015; published online October 15, 2015. Assoc. Editor: Haofeng Chen.

J. Pressure Vessel Technol 138(2), 021404 (Oct 15, 2015) (8 pages) Paper No: PVT-15-1058; doi: 10.1115/1.4031662 History: Received April 08, 2015; Revised September 15, 2015

A constraint loss correction procedure using the Weibull stress criterion is specified in ISO 27306. However, this standard is applicable only to structural steel components with defects, not to welded joints. Therefore, we propose a method for estimating the brittle fracture limit of a weld with a notch in the heat-affected zone (HAZ) and residual stress based on the Weibull stress criterion. Three-point bending (3PB) tests and wide-plate (WP) tension tests of HAZ-notched welds made of 780-MPa class high-strength steel were conducted at −40 °C. The minimum critical crack tip opening displacement (CTOD) of the WP specimen fracturing at the coarse-grained region of the HAZ (CGHAZ) was approximately four times that of the 3PB specimen. Then, the effects of specimen geometry, residual stress, crack-front shape, and HAZ microstructure classification on the Weibull stress were investigated by using a finite element analysis (FEA). The results of these analyses showed that the specimen geometry, the welding residual stress, and HAZ microstructure affect the Weibull stress of HAZ-notched welds as crack driving force. Based on above results, the CTOD–Weibull stress curves for 3PB and WP specimens fracturing at CGHAZ were calculated by using an FEA. It was confirmed that the brittle fracture limit of an HAZ-notched weld with residual stress could be predicted from the Weibull stress criterion because predicted critical CTOD of WP specimens obtained by Weibull stress included experimental critical CTOD of WP specimens.

Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.

References

BS 7910:2005, 2005, Guide to Methods for Assessing the Acceptability of Flaws in Fusion Welded Structures, British Standard Institution, London, UK.
WES 2805-1980, 1980, Method of Assessment for Defects in Fusion Welded Joints With Respect to Brittle Fracture, The Japan Welding Engineering Society, Tokyo, Japan.
Bermin, F. M. , 1983, “ A Local Criterion for Cleavage Fracture of a Nuclear Pressure Vessel Steel,” Metall. Trans. A, 14(11), pp. 2277–2287. [CrossRef]
Mudry, F. , 1987, “ A Local Approach to Cleavage Fracture,” Nucl. Eng. Des., 105(1), pp. 65–76. [CrossRef]
ISO 27306, 2009, Method of Constraint Loss Correction of CTOD Fracture Toughness for Fracture Assessment of Steel Components, International Organization for Standardization, Geneva, Switzerland.
Minami, F. , 1996, “ Fracture Toughness Requirement for Fracture Performance Evaluation of Welded Joints Based on the Local Approach,” 15th ASME International Conference on Offshore Mechanics and Arctic Engineering, Florence, Italy, June 16–20, pp. 193–202.
Minami, F. , 1997, “ Prediction of Specimen Geometry Effect on Fracture Resistance of HAZ-Notched Welds by Local Approach,” Mis-Matching of Interfaces and Welds, GKSS Research Centre, Geesthacht, Germany, pp. 319–330.
Sakimoto, T. , 2012, “ Constraint Loss Correction Between SENB and SENT for Welded Joint Specimens Based on Weibull Stress Criterion,” 22nd International Offshore and Polar Engineering Conference, Rhodes, Greece, June 17–22, pp. 147–152.
Gunnert, R. , 1962, “ Measuring of Residual Stresses and Strains,” International Institute of Welding, Villepinte, France, Technical Report No. IIW-X-288-62.
BS 7448, 1991, Fracture Mechanics Toughness Tests, Part 1, British Standard Institution, London, UK.
API RP 2Z-2005, 2005, Recommended Practice for Preproduction Qualification for Steel Plates for Offshore Structures, American Petroleum Institute, Washington, DC.
Satoh, K. , 1988, “ HAZ Fracture Toughness Testing and Utilization of Toughness Data to Structural Integrity,” 7th International Conference on Offshore Mechanics and Arctic Engineering, Houston, TX, pp. 495–502.
Minami, F. , 1992, “ Estimation Procedure for the Weibull Parameters Used in the Local Approach,” Int. J. Fract., 54(3), pp. 197–210.
Yamashita, Y. , and Minami, F. , 2010, “ Constraint Loss Correction for Assessment of CTOD Fracture Toughness Under Welding Residual Stress. Part I: Methodology Using the Equivalent CTOD Ratio,” Eng. Fract. Mech., 77(12), pp. 2213–2232. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Cross section of welded joint

Grahic Jump Location
Fig. 2

Nominal stress–strain curves of base and weld metals

Grahic Jump Location
Fig. 3

Distribution of transverse residual stress measured by released-strain method

Grahic Jump Location
Fig. 4

Geometry of test specimens: (a) 3PB specimen and (b) WP specimen

Grahic Jump Location
Fig. 5

Fracture surfaces of (a) 3PB specimen and (b) WP tension specimen

Grahic Jump Location
Fig. 6

Critical CTOD of 3PB and WP specimens at brittle fracture initiation

Grahic Jump Location
Fig. 7

Relationship between critical CTOD value and total CGHAZ size for HAZ-notched specimen

Grahic Jump Location
Fig. 8

FE model of (a) 3PB and (b) WP specimens

Grahic Jump Location
Fig. 9

Microstructure distribution for FEA

Grahic Jump Location
Fig. 10

True stress–true plastic strain curves of materials used for FEA

Grahic Jump Location
Fig. 11

Crack opening stress distribution at CTOD = 0.019, 0.043, and 0.085 mm

Grahic Jump Location
Fig. 12

Effect of specimen geometry on the Weibull stress

Grahic Jump Location
Fig. 13

Results of introducing residual stress: (a) welding plate model after generating welding residual stress and (b) distribution of transverse residual stress

Grahic Jump Location
Fig. 14

Effect of residual stress on Weibull stress for 3PB and WP specimens

Grahic Jump Location
Fig. 15

Effects of compressive residual stress generated by fatigue loading on Weibull stress for 3PB and WP specimens

Grahic Jump Location
Fig. 16

Crack-front shape of each model

Grahic Jump Location
Fig. 17

Effects of crack-front shape on Weibull stress for 3PB specimens

Grahic Jump Location
Fig. 18

Microstructure distribution B

Grahic Jump Location
Fig. 19

Effects of microstructure distribution on Weibull stress for 3PB and WP specimens

Grahic Jump Location
Fig. 20

Relationship between CTOD and Weibull stress for 3PB and WP specimens fracturing at CGHAZ

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In