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ML00051 - Apr.2020

Chloride SCC of 316 Heat Exchanger Plate

Micrography of the plate material presenting a granular austenitic structure, free from precipitation.

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of the material presenting a austenitic , free from precipitation.
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Material

Austenitic Stainless Steel
  • UNS S31600
  • NF EN NF EN 10088 X2CrNiMo17-12-2
  • AISI 316
Ds

Description

This 316 cold formed thin worked during a short time transfering the heat between hot water (temperature around 140°C) and high salinity crude oil. The combination of , high chloride content and a material that is susceptible to (CSCC) was responsible for the failure.

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Chemistry (% in weight)

Product Analysis

0.038C; 0.36Si; 1.16Mn; 0.029P; 0.006S; 17.4Cr; 10.0Ni; 1.9Mo; 0.19Cu.

Associated Images
Aspect of the heat exchanger plate showing the rupture of the plate in multiple cracks, starting at the side of the crude oil with high salinity.
729
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Aspect Before AnalysisDf - Cracking
Macrography of the surface of the cracked heat exchanger plate, manufactured in austenitic stainless steel.
159
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Macro Oxalic Acid Electrolytic EtchedDf - Cracking
Micrography of the plate material presenting a granular austenitic structure, free from precipitation.
122
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Eletrolytically Etched Micrography by OMDf - Austenite
Micrographic detail of the austenitic microstructure of the heat exchanger plate, free from carbides that suggest the adoption of a material in a solution annealed condition, although the high hardness level indicates cold working.
109
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Eletrolytically Etched Micrography by OMDf - Austenite
Micrography presenting the transgranular morphology of the stress corrosion cracks of the austenitic plate. EDS analysis at the plate surface indicated high Cl peaks.
111
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Eletrolytically Etched Micrography by OMDf - Corrosion Cracking
Micrographic detail of a branch transgranular crack typical of CSCC. Moreover, there is no evidence of intergranular precipitation.
99
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Micrography by OM using A262 Method ADf - Corrosion Cracking