Cracking of ferritic stainless steel tubes during production process

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378297%3A_____%2F15%3A00455714" target="_blank" >RIV/68378297:_____/15:00455714 - isvavai.cz</a>

Alternative codes found

RIV/25794787:_____/15:#0000616

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Cracking of ferritic stainless steel tubes during production process

Original language description

From the economic reasons many products originally made from austenite stainless steel are nowadays made from ferritic stainless steel. Ferritic steels have relatively low yield strength and the work hardening is limited. They cannot be hardened by heat treatment and only moderately hardened by cold working. Commercially made stainless steel tubes from ferritic steel, used for industrial plumbing was examined on presence of cracks. The cracking was present on the inner side of the convoluted tube shape. The tube manufacturing process consisted of continual bending of the sheet to tube shape, weld the tube, then of cold shaping by pulling through rib-forming frames, which is done in several steps. Then thermal treatment applies to the nearly finished product to remove stress remaining in the structure. Prime suspect was deformation beyond the ductility of used material. However the stress-strain tensile testing does not approved this hypothesis. Several samples of failed material were taken together with reference, and were examined by optical microscopy, and X-Ray Diffraction structure analysis. The structure of the cracked tubes does not show the signs of deformation over the limit, except the location near to the crack itself. Interestingly enough the failed material showed more homogenous structure than the original one. Needle like structures were found when the material is “overetched”, on these structures concentration of stress under bending occur. This structure was identified as δ-ferrite, however its presence in α-ferrite matrix is unclear.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

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OECD FORD branch

20506 - Coating and films

Project

<a href="/en/project/LO1219" target="_blank" >LO1219: Sustainable advanced development of CET</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2015

Confidentiality

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

Article name in the collection

METAL 2015. Conference proceedings

ISBN

978-80-87294-62-8

ISSN

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e-ISSN

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Number of pages

5

Pages from-to

768-772

Publisher name

TANGER

Place of publication

Ostrava

Event location

Brno

Event date

Jun 3, 2015

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

000374706100122