Evalution of Micro-Fracture Mechanisms and Fracture Toughness of Cryogenic Structural Steels and Weldment

Keita Ohnishi; Tetsuo Shoji; Hideaki Takahashi

doi:10.1299/kikaia.52.170

Evalution of Micro-Fracture Mechanisms and Fracture Toughness of Cryogenic Structural Steels and Weldment

Keita Ohnishi, Tetsuo Shoji, Hideaki Takahashi

New Industry Creation Hatchery Center (NICHe)

Research output: Contribution to journal › Article

Abstract

In order to evaluate the fracture toughness of structural steels for superconducting magnets of fusion reactor, elastic-plastic fracture toughness testing was performed at 4.2 K on AISI 310S base metal, weld metal and 20 Mn steel. Fracture toughnesses were evaluated by a single specimen technique using the Key Curve reported previously. Elastic-plastic fracture toughness J_1C and tearing modulus T_mat of weld metal were significantly lower than those of base metal. As the result of AE measurement, microfracturing was detected at the early stage of loading, and pop-in cracking was observed at the later stage. Fractographic and metallographic examination of fracture surfaces and fracture paths revealed a difference in dimple sizes between the weld metal and the base metal, and also micro void formation ahead of a growing crack tip, which resulted in smaller crack opening angle of the weld metal than the base metal. Finally, the significance of crack growth analysis of the weld metal was emphasized to ensure the structural integrity of superconducting magnet.

Original language	English
Pages (from-to)	170-173
Number of pages	4
Journal	Transactions of the Japan Society of Mechanical Engineers Series A
Volume	52
Issue number	473
DOIs	https://doi.org/10.1299/kikaia.52.170
Publication status	Published - 1986 Jan 1

Keywords

Acoustic Emission
Elastic-Plastic Fracture Toughness
Fracture
J-Integral
Key Curve Method
Structure Steels. Cryogenic Temperature
Superconducting Magnet
Weld Metal

ASJC Scopus subject areas

Materials Science(all)
Mechanics of Materials
Mechanical Engineering

Access to Document

10.1299/kikaia.52.170

Fingerprint Dive into the research topics of 'Evalution of Micro-Fracture Mechanisms and Fracture Toughness of Cryogenic Structural Steels and Weldment'. Together they form a unique fingerprint.

Cite this

@article{cd233c981cfe46b09a77ae4ffb7b0048,

title = "Evalution of Micro-Fracture Mechanisms and Fracture Toughness of Cryogenic Structural Steels and Weldment",

abstract = "In order to evaluate the fracture toughness of structural steels for superconducting magnets of fusion reactor, elastic-plastic fracture toughness testing was performed at 4.2 K on AISI 310S base metal, weld metal and 20 Mn steel. Fracture toughnesses were evaluated by a single specimen technique using the Key Curve reported previously. Elastic-plastic fracture toughness J1C and tearing modulus Tmat of weld metal were significantly lower than those of base metal. As the result of AE measurement, microfracturing was detected at the early stage of loading, and pop-in cracking was observed at the later stage. Fractographic and metallographic examination of fracture surfaces and fracture paths revealed a difference in dimple sizes between the weld metal and the base metal, and also micro void formation ahead of a growing crack tip, which resulted in smaller crack opening angle of the weld metal than the base metal. Finally, the significance of crack growth analysis of the weld metal was emphasized to ensure the structural integrity of superconducting magnet.",

keywords = "Acoustic Emission, Elastic-Plastic Fracture Toughness, Fracture, J-Integral, Key Curve Method, Structure Steels. Cryogenic Temperature, Superconducting Magnet, Weld Metal",

author = "Keita Ohnishi and Tetsuo Shoji and Hideaki Takahashi",

year = "1986",

month = jan,

day = "1",

doi = "10.1299/kikaia.52.170",

language = "English",

volume = "52",

pages = "170--173",

journal = "Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A",

issn = "0387-5008",

publisher = "Japan Society of Mechanical Engineers",

number = "473",

}

TY - JOUR

T1 - Evalution of Micro-Fracture Mechanisms and Fracture Toughness of Cryogenic Structural Steels and Weldment

AU - Ohnishi, Keita

AU - Shoji, Tetsuo

AU - Takahashi, Hideaki

PY - 1986/1/1

Y1 - 1986/1/1

N2 - In order to evaluate the fracture toughness of structural steels for superconducting magnets of fusion reactor, elastic-plastic fracture toughness testing was performed at 4.2 K on AISI 310S base metal, weld metal and 20 Mn steel. Fracture toughnesses were evaluated by a single specimen technique using the Key Curve reported previously. Elastic-plastic fracture toughness J1C and tearing modulus Tmat of weld metal were significantly lower than those of base metal. As the result of AE measurement, microfracturing was detected at the early stage of loading, and pop-in cracking was observed at the later stage. Fractographic and metallographic examination of fracture surfaces and fracture paths revealed a difference in dimple sizes between the weld metal and the base metal, and also micro void formation ahead of a growing crack tip, which resulted in smaller crack opening angle of the weld metal than the base metal. Finally, the significance of crack growth analysis of the weld metal was emphasized to ensure the structural integrity of superconducting magnet.

AB - In order to evaluate the fracture toughness of structural steels for superconducting magnets of fusion reactor, elastic-plastic fracture toughness testing was performed at 4.2 K on AISI 310S base metal, weld metal and 20 Mn steel. Fracture toughnesses were evaluated by a single specimen technique using the Key Curve reported previously. Elastic-plastic fracture toughness J1C and tearing modulus Tmat of weld metal were significantly lower than those of base metal. As the result of AE measurement, microfracturing was detected at the early stage of loading, and pop-in cracking was observed at the later stage. Fractographic and metallographic examination of fracture surfaces and fracture paths revealed a difference in dimple sizes between the weld metal and the base metal, and also micro void formation ahead of a growing crack tip, which resulted in smaller crack opening angle of the weld metal than the base metal. Finally, the significance of crack growth analysis of the weld metal was emphasized to ensure the structural integrity of superconducting magnet.

KW - Acoustic Emission

KW - Elastic-Plastic Fracture Toughness

KW - Fracture

KW - J-Integral

KW - Key Curve Method

KW - Structure Steels. Cryogenic Temperature

KW - Superconducting Magnet

KW - Weld Metal

UR - http://www.scopus.com/inward/record.url?scp=0022497616&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0022497616&partnerID=8YFLogxK

U2 - 10.1299/kikaia.52.170

DO - 10.1299/kikaia.52.170

M3 - Article

AN - SCOPUS:0022497616

VL - 52

SP - 170

EP - 173

JO - Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A

JF - Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A

SN - 0387-5008

IS - 473

ER -