PSI - Issue 17

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 17 (2019) 526–531

ICSI 2019 The 3rd International Conference on Structural Integrity Analysis of cracks propagated in a tee pipe fitting C. Medrea a,* , E. Pappa a , D.G. Papageorgiou a,b , C. Stergiou a a Department of Mechanical Engineering, University of West Attica, 250 Thivon & Petrou Ralli Str.,12244, Egaleo, Greece b Stassinopoulos-Uddeholm, Steel Trading S. A., 20 Athinon Str. 18540 Piraeus, Greece ICSI 2019 The 3rd International Conference on Structural Integrity Analysis of cracks propagated in a tee pipe fitting C. Medrea a,* , E. Pappa a , D.G. Papageorgiou a,b , C. Stergiou a a Department of Mechanical Engineering, University of West Attica, 250 Thivon & Petrou R lli Str.,12244, Egaleo, Greece b Stassinopoulos-Uddeholm, Steel Trading S. A., 20 Athinon Str. 18540 Piraeus, Greece The work investigates the cracks propagated in a tee pipe fitting, part of desulphurization units of an oil refinery company. The part was extracted from an assembly that was manufactured and installed by the refinery maintenance department. The research covers the typical experimental procedure of failure analysis and focused on the cracks examination. Historical data were recorded. The chemical composition of the material was verified. The component was examined and photographed as received. A superheated inlet steam meets a lower temperature inlet steam, mixes on specific areas and comes out of a common outlet. A network of cracks was detected on the mixing areas. Samples were selected and prepared according to the analysis procedure. Both outer and inner surfaces of the fragmented tee pipe were inspected with penetrant liquid. The crack origin and propagation were detected and fracture mode was identified. Selected specimens were macro etched and inspected visually, revealing numerous welding defects. Tee pipe fitting failed on the mixing area. It cracked by thermal fatigue due to simultaneous effect of stress and temperature. Furthermore, poor welding facilitated the crack process. The work investigates the cracks propagated in a tee pipe fitting, part of desulphurization units of an oil refinery company. The part was extracted from an assembly that was manufactured and installed by the refinery maintenance department. The research covers the typical experimental procedure of failure analysis and focused on the cracks examination. Historical data were recorded. The chemical co position of the material was verified. The component was examined and photographed as received. A superheated inlet steam meets a lower temperature inlet steam, mixes on specific areas and comes out of a common outlet. A network of cracks was detected on the mixing areas. Samples were selected and prepared according to the analysis procedure. Both outer and inner surfaces of the fragmented tee pipe were inspected with penetrant liquid. The crack origin and propagation were detected and fracture mode was identified. Selected specimens were macro etched and inspected visually, revealing numerous welding defects. Tee pipe fitting failed on the mixing area. It cracked by thermal fatigue due to simultaneous effect of stress and temperature. Furthermore, poor welding facilitated the crack process. Abstract Abstract

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers.

Keywords: thermal fatigue; tee pipe fitting; incololy 800H steel; petroleum refinery; desulphurization unit; poor welding; Keywords: thermal fatigue; tee pipe fitting; incololy 800H steel; petroleum refinery; desulphurization unit; poor welding;

1. Introduction 1. Introduction

Petroleum refineries get various types of fuels and have an important position in the global financial growth (Kraus, 2011). Due to the increasing economical requirements, refining facilities enhance production efficiency and consequently minimize their operational cost. The refinery processes the crude oil, by heating it in furnaces (Fig. 1); then through fractionating columns (or distillation towers) convert it into various oil fractions, according to the Petroleum refineries get various types of fuels and have an important position in the global financial growth (Kraus, 2011). Due to the increasing economical requirements, refining facilities enhance production efficiency and consequently minimize their operational cost. The refinery processes the crude oil, by heating it in furnaces (Fig. 1); then through fractionating columns (or distillation towers) convert it into various oil fractions, according to the

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. * Carmen Medrea. Tel.: +302107651041; fax: +302105381165. E-mail address: cmedrea@uniwa.gr * Carmen Medrea. Tel.: +302107651041; fax: +302105381165. E-mail address: cmedrea@uniwa.gr

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 10.1016/j.prostr.2019.08.070