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ML00128 - Apr.2018

MIC of a Stored Hydraulic Cylinder

Aspect of the hydraulic cylinder surface presenting white stains in a region where the damage was still in the begining.

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Aspect of the hydraulic cylinder surface presenting white stains in a region where the was still in the begining.
M

Material

Low Carbon Steel
  • DIN 1.0562
  • EN 10253-2 grade P355N
Ds

Description

After three months stored in a tropical environment under a plastic cover, the plated cylinder presented stains and regions of detachment of the layer under deposits. The metallurgical characterization evidenced two metallic layers ( and Cr), as specified. The deposits (fouling) were generated by microorganism and a was responsible for the . The Ni layer was still and the substrate was not exposed yet.

C

Chemistry (% in weight)

Mild Steel + Ni and Cr layers

0.2C.

Associated Images
Scanning electron microscopy image of the chromium plated cylinder surface, presenting deposits and localized dissolution under deposits. There are different stages of corrosion in this region, observed in low magnification. Small areas of attack and a shallow pitting with deposits that were analyzed by EDS and revealed the presence of S.
903
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Surface Aspect by SEMDf - Localized Corrosion
Aspect of the hydraulic cylinder, new, stored in tropical conditions under a plastic cover, that allowed a condensation condition and damage.
92
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Aspect Before AnalysisDf - General View
Aspect of the hydraulic cylinder surface presenting white stains in a region where the damage was still in the begining.
73
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Aspect Before AnalysisDf - External Surface
Aspect of the hydraulic cylinder surface presenting white stains and black oxides in a region that started a localized dissolution under deposit.
72
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Aspect Before AnalysisDf - Corrosion
Detail of the cylinder external surface, with deep dissolution as the worst damage morphology.
65
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Aspect Before AnalysisDf - Corrosion
As polished micrographic aspect of the longitudinal section of the cylinder, at the surface, in a region where the damage is in the begining. It is possible to see that there are two layers at the surface. A first Ni layer, 300HV average hardness, over the low carbon steel substrate, 200HV average hardness, and a chromium plated layer, 1100HV average hardness and several discontinuities.
62
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Micrography by OMDf - Longitudinal Section
Micrographic aspect of the Cr layer at the surface presenting incipient damage. Microcracks of the Cr layer, associated to small pits.
62
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Micrography by OMDf - Cracks
Micrographic aspect, after Nital etching, of the longitudinal section of the cylinder, at the surface, in a region where the damage is in the begining. There are two layers at the surface. A first Ni layer, 160 microns thick and 300HV average hardness, over the low carbon steel substrate, 200HV average hardness, and a chromium plated layer, 250 microns thick and 1100HV average hardness.
59
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Corrosion
Micrographic detail of the longitudinal section of the cylinder, at the surface, in a region where the Cr layer is detaching.
56
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Corrosion
Micrographic aspect of the longitudinal section of the cylinder steel substrate, presenting a ferritic-pearlitic structure.
207
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the ferritic-pearlitic structure of the cylinder steel substrate.
41
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of the longitudinal section of the cylinder , at the surface, where it was not yet damaged. The steel substrate is in the bottom of the figure, the Ni layer is in the center and the Cr layer is in the top of the figure.
38
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Ni layer
Micrography of the interface between the steel substrate and the first Ni layer. The Ni layer, 160 microns thick and 300HV hardness, is uniform and presents no discontinuities.
37
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Ni layer
Micrography of the interface between the Ni layer (bottom) and the Cr layer (top of the figure). The Cr layer, 250 microns thick and 1100HV hardness, presents small pores and cracks (that appear like black shadows, not focused).
36
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Hard Chromium Layer
Detail of a localized dissolution at the surface of the chromium plated cylinder. Note the dimension of the corrosion pitting, shallow.
33
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Aspect Before AnalysisDf - At the Surface
Scanning electron microscopy image of the chromium plated surface in a position where the cylinder was not damaged, showing the surface finishing.
35
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Surface Aspect by SEMDf - At the Surface
Scanning electron microscopy image of the chromium plated cylinder in a region of localized dissolution under deposit. Inside the shallow pitting the Cr structure with a network of layers is revealed by the etching effect promoted by microbiollogically induced corrosion.
35
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Surface Aspect by SEMDf - Corrosion
Scanning electron microscopy image in detail of the chromium plated cylinder surface in a region of localized dissolution. The surface shows several microcracks promoted by the effects of the microbiollogically induced corrosion. Inside the corroded pit the network of the chromium layer is evidenced by the MIC attack.
48
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Surface Aspect by SEMDf - Corrosion