Hydrogen Embirttlement in Weldox 1300 and Hardox 500
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Upon trying to reach higher strengths, when designing steels, inevitably susceptibility to one
type of cracking known as hydrogen cracking increases. In present work, this complexity with
regard to high strength structural steel of Weldox 1300 and wear plate of Hardox 500 was
Effect of low temperature tempering (200 ) and hard leveling on hydrogen embrittlement was
qualitatively explored by fracture toughness testing. Tests were performed on SENB specimens of two types of Weldox 1300 in air and 3.5% NaCl solution. In-situ testing of as-quenched Weldox caused K value for crack growth initiation to drop to almost 20% of that for reference specimen tested in air. However, Weldox 1300 in tempered and leveled condition exhibited considerably improved resistance against hydrogen cracking by almost 50% compared to asquenched condition.
It is believed that formation of transit carbides acting as strong traps due to tempering, and alteration in dislocations’ structure and level of tensile residual stresses thanks to combined effects of tempering and leveling have considerable impact on crack growth kinetics which results in improved resistance. The influence of tempering and leveling was not investigated separately.
Additionally, by using four-point-bending test it was attempted to screen a method suitable for study of hydrogen embrittlement. Test variables were tried to be adjusted to meet the failure criteria. Precharged samples were subjected to bending stresses and left in outdoor atmosphere. Hydrogen measurement after passing 41 days on one of the samples containing a stress concentrator showed that hydrogen had been trapped and still present into the sample. Although hydrogen measurement showed the effect of stress fields on hydrogen trapping, test results along with FEM simulation indicated that such a test method might not be practicable for this special combination of materials and expectations.
Place, publisher, year, edition, pages
Hydrogen Damage, Hydrogen Embrittlement, Linear Elastic Fracture Toughness, Low Temperature Tempering
Mechanical Engineering Materials Engineering
IdentifiersURN: urn:nbn:se:kth:diva-143334OAI: oai:DiVA.org:kth-143334DiVA: diva2:706283
Subject / course
Materials and Process Design
Master of Science - Materials Science and Engineering
Efsing, Pål, Professor
Eliasson, Anders, Associate Professor
To access the full report please contact Department of Solid Mechanics, Teknikringen 8 D, 1st and 2nd floor.2014-05-212014-03-192014-05-21Bibliographically approved