Role of Nb in the failure of dual-phase steel in heterogeneous welds

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25510%2F20%3A39916170" target="_blank" >RIV/00216275:25510/20:39916170 - isvavai.cz</a>

Result on the web

<a href="https://www.sciencedirect.com/science/article/abs/pii/S1350630720308384?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/abs/pii/S1350630720308384?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.engfailanal.2020.104708" target="_blank" >10.1016/j.engfailanal.2020.104708</a>

Result language

angličtina

Original language name

Role of Nb in the failure of dual-phase steel in heterogeneous welds

Original language description

The use of Cr-Ni austenitic steel interlayers is an effective solution for heterogeneous welds, especially in combination with high-carbon steels. High contact-fatigue resistance and resistance to impact loads are required in the case of railway crossing applications. The failure of Nb-alloyed cast Cr-Ni austenitic steel used as an insert in the flash butt resistance weld of Hadfield steel with carbon steel is the subject of the presented analyses. The identification of the failure mechanism is based on light and scanning electron microscopy and energy dispersive X-ray analyses, including electron backscattered analyses. The initiation of hot-crack defects is detected in the heat affected zone (HAZ). In contrast to the usual conditions for the formation of hot cracks in the HAZ, cracks are found solely outside the superheating zone. The decisive influence of Nb-based intermetallics formed at the phase interface of delta-ferrite and the austenitic matrix is indicated. The eutectics formation between niobium carbonitrides and the austenitic matrix is assumed to be responsible for the hot-cracking susceptibility of austenitic steel. The particular combination of the temperature gradient together with the chemical gradient leading to a localization of the critical zone is documented. The paper describes the influence of carbon redistribution at the weld interface on the morphology of delta-ferrite in different layers of the heat-affected zone. Induced structural differences are associated with Nb-particle formation. Fractographic analyses show the formation of low-melting phases in the critical layer of the HAZ. The influence of secondary phases, especially Nb-eutectic, on the degradation of austenitic steel plasticity is documented.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

20501 - Materials engineering

Project

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Continuities

S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Engineering Failure Analysis

ISSN

1350-6307

e-ISSN

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Volume of the periodical

116

Issue of the periodical within the volume

october 2020

Country of publishing house

GB - UNITED KINGDOM

Number of pages

13

Pages from-to

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UT code for WoS article

000567791900008

EID of the result in the Scopus database

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