Slow strain rate tensile test properties of iron-based superalloy SUH660 in hydrogen gas

Research output: Contribution to journalArticle

Abstract

To investigate dependence of strain rate of tensile test for iron-based superalloy SUH660 (A286), tensile tests were conducted for the specimens in 70 MPa hydrogen gas and air at 150°C. Nominal stress-nominal strain curve of each strain rate in 70 MPa hydrogen gas showed same behavior to maximum load via yield point in comparison with that in air, however, each elongation at breaking point in 70 MPa hydrogen was a little shorter than that in air. The values of tensile strength didn't depend on the strain rate in 70 MPa hydrogen as well as those in air. In addition, the difference in tensile strength wasn't observed between that in 70 MPa hydrogen gas and that in air for the strain rate. However, it's proved that relative reduction of area in 70 MPa hydrogen to that in air was significantly affected by strain rate of tensile test. Those values were 80%, 51%, and 32% in the case of strain rate 5.0×10-5, 7.5×10-6, and 1.25×10-6 s-1, respectively. The morphology of fracture surface also changed from dimple to quasi-cleavage (QC), with a decrease in strain rate. Simulation of hydrogen gas diffusion form surface to inside during experiment showed that the hydrogen diffusion layer of specimen with QC fracture surface (RRA 51%, strain rate 7.5×10-6 s-1) was only 0.25 mm in depth. That implies that hydrogen content at crack tips is much higher than that of simulation due to hydrogen concentration by a couple of defects. That tendency seems to become stronger with a decrease in strain rate.

Original languageEnglish
Pages (from-to)338-345
Number of pages8
JournalTetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan
Volume104
Issue number6
DOIs
Publication statusPublished - 2018 Jun 1
Externally publishedYes

Fingerprint

heat resistant alloys
tensile tests
Superalloys
strain rate
Strain rate
Hydrogen
Iron
Gases
iron
hydrogen
gases
air
Air
tensile strength
cleavage
Tensile strength
gaseous diffusion
Diffusion in gases
crack tips
yield point

Keywords

  • A286
  • Dimple
  • Hydrogen embrittlement
  • Quasi-cleavage fracture
  • Reduction of area
  • Relative reduction of area
  • Slow strain rate tensile test
  • SUH660

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Metals and Alloys
  • Materials Chemistry

Cite this

@article{1f5a592e63a847c1900896c6df476792,
title = "Slow strain rate tensile test properties of iron-based superalloy SUH660 in hydrogen gas",
abstract = "To investigate dependence of strain rate of tensile test for iron-based superalloy SUH660 (A286), tensile tests were conducted for the specimens in 70 MPa hydrogen gas and air at 150°C. Nominal stress-nominal strain curve of each strain rate in 70 MPa hydrogen gas showed same behavior to maximum load via yield point in comparison with that in air, however, each elongation at breaking point in 70 MPa hydrogen was a little shorter than that in air. The values of tensile strength didn't depend on the strain rate in 70 MPa hydrogen as well as those in air. In addition, the difference in tensile strength wasn't observed between that in 70 MPa hydrogen gas and that in air for the strain rate. However, it's proved that relative reduction of area in 70 MPa hydrogen to that in air was significantly affected by strain rate of tensile test. Those values were 80{\%}, 51{\%}, and 32{\%} in the case of strain rate 5.0×10-5, 7.5×10-6, and 1.25×10-6 s-1, respectively. The morphology of fracture surface also changed from dimple to quasi-cleavage (QC), with a decrease in strain rate. Simulation of hydrogen gas diffusion form surface to inside during experiment showed that the hydrogen diffusion layer of specimen with QC fracture surface (RRA 51{\%}, strain rate 7.5×10-6 s-1) was only 0.25 mm in depth. That implies that hydrogen content at crack tips is much higher than that of simulation due to hydrogen concentration by a couple of defects. That tendency seems to become stronger with a decrease in strain rate.",
keywords = "A286, Dimple, Hydrogen embrittlement, Quasi-cleavage fracture, Reduction of area, Relative reduction of area, Slow strain rate tensile test, SUH660",
author = "Akihiko Fukunaga",
year = "2018",
month = "6",
day = "1",
doi = "10.2355/tetsutohagane.TETSU-2017-084",
language = "English",
volume = "104",
pages = "338--345",
journal = "Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan",
issn = "0021-1575",
publisher = "Iron and Steel Institute of Japan",
number = "6",

}

TY - JOUR

T1 - Slow strain rate tensile test properties of iron-based superalloy SUH660 in hydrogen gas

AU - Fukunaga, Akihiko

PY - 2018/6/1

Y1 - 2018/6/1

N2 - To investigate dependence of strain rate of tensile test for iron-based superalloy SUH660 (A286), tensile tests were conducted for the specimens in 70 MPa hydrogen gas and air at 150°C. Nominal stress-nominal strain curve of each strain rate in 70 MPa hydrogen gas showed same behavior to maximum load via yield point in comparison with that in air, however, each elongation at breaking point in 70 MPa hydrogen was a little shorter than that in air. The values of tensile strength didn't depend on the strain rate in 70 MPa hydrogen as well as those in air. In addition, the difference in tensile strength wasn't observed between that in 70 MPa hydrogen gas and that in air for the strain rate. However, it's proved that relative reduction of area in 70 MPa hydrogen to that in air was significantly affected by strain rate of tensile test. Those values were 80%, 51%, and 32% in the case of strain rate 5.0×10-5, 7.5×10-6, and 1.25×10-6 s-1, respectively. The morphology of fracture surface also changed from dimple to quasi-cleavage (QC), with a decrease in strain rate. Simulation of hydrogen gas diffusion form surface to inside during experiment showed that the hydrogen diffusion layer of specimen with QC fracture surface (RRA 51%, strain rate 7.5×10-6 s-1) was only 0.25 mm in depth. That implies that hydrogen content at crack tips is much higher than that of simulation due to hydrogen concentration by a couple of defects. That tendency seems to become stronger with a decrease in strain rate.

AB - To investigate dependence of strain rate of tensile test for iron-based superalloy SUH660 (A286), tensile tests were conducted for the specimens in 70 MPa hydrogen gas and air at 150°C. Nominal stress-nominal strain curve of each strain rate in 70 MPa hydrogen gas showed same behavior to maximum load via yield point in comparison with that in air, however, each elongation at breaking point in 70 MPa hydrogen was a little shorter than that in air. The values of tensile strength didn't depend on the strain rate in 70 MPa hydrogen as well as those in air. In addition, the difference in tensile strength wasn't observed between that in 70 MPa hydrogen gas and that in air for the strain rate. However, it's proved that relative reduction of area in 70 MPa hydrogen to that in air was significantly affected by strain rate of tensile test. Those values were 80%, 51%, and 32% in the case of strain rate 5.0×10-5, 7.5×10-6, and 1.25×10-6 s-1, respectively. The morphology of fracture surface also changed from dimple to quasi-cleavage (QC), with a decrease in strain rate. Simulation of hydrogen gas diffusion form surface to inside during experiment showed that the hydrogen diffusion layer of specimen with QC fracture surface (RRA 51%, strain rate 7.5×10-6 s-1) was only 0.25 mm in depth. That implies that hydrogen content at crack tips is much higher than that of simulation due to hydrogen concentration by a couple of defects. That tendency seems to become stronger with a decrease in strain rate.

KW - A286

KW - Dimple

KW - Hydrogen embrittlement

KW - Quasi-cleavage fracture

KW - Reduction of area

KW - Relative reduction of area

KW - Slow strain rate tensile test

KW - SUH660

UR - http://www.scopus.com/inward/record.url?scp=85048051567&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85048051567&partnerID=8YFLogxK

U2 - 10.2355/tetsutohagane.TETSU-2017-084

DO - 10.2355/tetsutohagane.TETSU-2017-084

M3 - Article

VL - 104

SP - 338

EP - 345

JO - Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan

JF - Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan

SN - 0021-1575

IS - 6

ER -