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ML00038 - Apr.2017

Cast SS Tube for High Temperature Service

Micrography, in the as polished condition, of the TUBE REMOVED FROM SERVICE, centrifugally cast, in the transverse section, presenting external surface oxides and voids.

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, in the condition, of the , centrifugally cast, in the , presenting oxides and .
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Material

Heat Resistant Steel
  • ASTM A 297 grade HP
Ds

Description

The HP centrifugally cast had suffered (microstructural evolution, and ) after one year operating in temperatures from 650°C to 950°C. The of the is compared with the microstructure of a new material.

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Chemistry (% in weight)

New Tube

0.40C; 1.14Si; 1.37Mn; 0.025P; 0.035S; 24.47Cr; 33.98Ni; 0.04Mo; 0.02Ti; 1.29Nb.

Tube Removed from Service

0.42C; 1.42Si; 1.36Mn; 0.025P; 0.039S; 24.84Cr; 33.92Ni; 0.05Mo; 0.03Ti; 1.29Nb.

Associated Images
Micrography of the transverse section of the NEW TUBE, in the center of the thickness, showing the austenitic structure with primary carbides network.
410
VIEW
ML00038 / Apr.2017
Cast SS Tube for High Temperature Service
M - Heat Resistant SteelP - Centrifugally Cast PipeAp - SiderurgyCd - Creep
Cm - Glyceregia Etched Micrography by OMDf - Austenitic with Primary Carbides
Micrography of the transverse section of the NEW TUBE, close to the external surface, showing the austenitic structure with primary carbides network.
59
VIEW
ML00038 / Apr.2017
Cast SS Tube for High Temperature Service
M - Heat Resistant SteelP - Centrifugally Cast PipeAp - SiderurgyCd - Creep
Cm - Glyceregia Etched Micrography by OMDf - Close to the External Surface
Macrography of the NEW TUBE, centrifugally cast, in the transverse section, presenting columnar grains close to the external surface.
50
VIEW
ML00038 / Apr.2017
Cast SS Tube for High Temperature Service
M - Heat Resistant SteelP - Centrifugally Cast PipeAp - SiderurgyCd - Creep
Cm - Kalling Etched MacroDf - Transverse Section
The micrography in the as polished condition of the NEW TUBE shows that there are no casting defects close to the external surface.
49
VIEW
ML00038 / Apr.2017
Cast SS Tube for High Temperature Service
M - Heat Resistant SteelP - Centrifugally Cast PipeAp - SiderurgyCd - Creep
Cm - Micrography by OMDf - Close to the External Surface
The micrography in the as polished condition of the NEW TUBE shows that there are no casting defects in the center of the thickness.
47
VIEW
ML00038 / Apr.2017
Cast SS Tube for High Temperature Service
M - Heat Resistant SteelP - Centrifugally Cast PipeAp - SiderurgyCd - Creep
Cm - Micrography by OMDf - Transverse Section
Micrography of the transverse section of the TUBE REMOVED FROM SERVICE, in the center of the thickness, showing the austenitic structure with primary carbides network and secondary precipitation.
59
VIEW
ML00038 / Apr.2017
Cast SS Tube for High Temperature Service
M - Heat Resistant SteelP - Centrifugally Cast PipeAp - SiderurgyCd - Creep
Cm - Glyceregia Etched Micrography by OMDf - Intragranular Secondary Precipitation
Micrography of the transverse section of the TUBE REMOVED FROM SERVICE,close to the external surface, showing the austenitic structure with coalesced carbides and secondary precipitation.
40
VIEW
ML00038 / Apr.2017
Cast SS Tube for High Temperature Service
M - Heat Resistant SteelP - Centrifugally Cast PipeAp - SiderurgyCd - Creep
Cm - Glyceregia Etched Micrography by OMDf - Close to the External Surface
Macrography of the TUBE REMOVED FROM SERVICE, centrifugally cast, in the transverse section, presenting thickness loss and macrostructure deterioration.
33
VIEW
ML00038 / Apr.2017
Cast SS Tube for High Temperature Service
M - Heat Resistant SteelP - Centrifugally Cast PipeAp - SiderurgyCd - Creep
Cm - Kalling Etched MacroDf - Transverse Section
Micrography, in the as polished condition, of the TUBE REMOVED FROM SERVICE, centrifugally cast, in the transverse section, presenting external surface oxides and voids.
35
VIEW
ML00038 / Apr.2017
Cast SS Tube for High Temperature Service
M - Heat Resistant SteelP - Centrifugally Cast PipeAp - SiderurgyCd - Creep
Cm - Micrography by OMDf - Voids
The micrography in the as polished condition of the TUBE REMOVED FROM SERVICE shows that after one year operating in high temperature the material opens voids in the center of the thickness. Even the secondary carbide is coalesced.
36
VIEW
ML00038 / Apr.2017
Cast SS Tube for High Temperature Service
M - Heat Resistant SteelP - Centrifugally Cast PipeAp - SiderurgyCd - Creep
Cm - Micrography by OMDf - Transverse Section