0
Research Papers: Materials and Fabrication

Prediction of Ductile-to-Brittle Transition Under Different Strain Rates in Undermatched Welded Joints

[+] Author and Article Information
Masahito Mochizuki1

Member of JSME, HPi-J, JWS, and AWS of Department of Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japanmmochi@mapse.eng.osaka-u.ac.jpDepartment of Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japanmmochi@mapse.eng.osaka-u.ac.jp

Masao Toyoda

Member of JSME, HPi-J, JWS, and AWS of Department of Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, JapanDepartment of Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan

1

Corresponding author.

J. Pressure Vessel Technol 133(3), 031401 (Mar 29, 2011) (8 pages) doi:10.1115/1.4002670 History: Received November 12, 2006; Revised August 25, 2009; Published March 29, 2011; Online March 29, 2011

A welded joint generally has heterogeneity of strength, material, and fracture toughness. It is important to understand the characteristics of the strength and fracture of welded joints while considering the heterogeneous effect. In particular, the material behavior becomes more complicated when the welded joint with strength heterogeneity is subjected to dynamic rapid loading; for example, the welded heat-affected zone of pipeline steels is softened and welded underground pipelines are affected by a rapid ground sliding in an earthquake. In this paper, the characteristics of the strength and fracture of an undermatched joint under dynamic loading are studied by round-bar tension tests and thermal elastic-plastic analyses. The results show that the strength and fracture characteristics of the undermatched joints should be evaluated based on the effects of the strain rate and the temperature, including the temperature rise during dynamic loading. The tensile strength and the yield stress of the undermatched joints increase with the strain rate and with the decreasing temperature. The strength of the undermatched zone approaches that of the base metal when the thickness of the undermatched zone becomes smaller, and it does not depend on the strain rate. Finally, it is found that the stress-strain distribution affects fracture characteristics such as ductile-to-brittle transition behavior. The fracture characteristics are explained and predicted from the results of stress-strain relations obtained by numerical analysis.

FIGURES IN THIS ARTICLE
<>
Copyright © 2011 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Conditions of heat treatment in diffusion bonding

Grahic Jump Location
Figure 2

Configuration of round-bar tension specimens of the undermatched joint and the definition of relative thickness: (a) undermatched joint and (b) relative thickness change of undermatched joint

Grahic Jump Location
Figure 3

Vickers hardness distribution along the longitudinal direction in the undermatched joint (X=0.3)

Grahic Jump Location
Figure 4

Relation between the yield stress and relative thickness in undermatched joints

Grahic Jump Location
Figure 5

Relation between the tensile strength and relative thickness in undermatched joints

Grahic Jump Location
Figure 6

Relation between the reduction of area and relative thickness in undermatched joints

Grahic Jump Location
Figure 7

Relation between the reduction of area at the interface of the materials and the relative thickness in undermatched joints

Grahic Jump Location
Figure 8

Comparison of ductile-to-brittle transition behavior in undermatched joints

Grahic Jump Location
Figure 9

Schematic of shift of the ductile-to-brittle transition temperature in undermatched joints: (a) effect of plastic constraint and (b) effect of strain rate and temperature rise

Grahic Jump Location
Figure 10

Comparison of the stress-strain curves and temperature rise in the round-bar tension specimen of undermatched joints obtained by experiment and FE analysis: (a) X=0.15 (100 mm/s at RT) and (b) X=1.0 (100 mm/s at −40°C)

Grahic Jump Location
Figure 11

Critical maximum loading stress for cleavage fracture in HT50 steel

Grahic Jump Location
Figure 12

Relation between the equivalent plastic strain and stress triaxiality for ductile fracture in HT50 steel

Grahic Jump Location
Figure 13

Critical lines of ductile fracture and brittle fracture and stress-strain behavior for undermatched joints (relative thickness X=0.15): (a) static loading and (b) dynamic loading

Grahic Jump Location
Figure 14

Critical lines of ductile fracture and brittle fracture and stress-strain behavior for undermatched joints (relative thickness X=1.0): (a) static loading and (b) dynamic loading

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