Back to Martensitic Stainless Steel
ML00017 - Apr.2017

Casting Defect in CA6NM

Linear indication in the sample, after metallographic preparation. The "cracking" is a casting defect.

3

65
Linear indication in the sample, after metallographic preparation. The "" is a defect.
M

Material

Martensitic Stainless Steel
  • UNS J91540
  • ASTM A 743 grade CA6NM
Ds

Description

The water turbine blade was inspected during maintenance and a linear indication was detected by . The defective region was removed and analyzed in the laboratory. The metallurgical analysis showed that the indication is an internal defect ( and shrinkage) opened to the surface during fabrication (machining).

C

Chemistry (% in weight)

Product Analysis

0.05C; 0.48Si; 0.90Mn; 0.033P; 0.017S; 13.1Cr; 3.5Ni; 0.52Mo.

Associated Images
Casting defect identified in the micrographic section, as polished, of the sample removed from the blade. The total lenght of the defect detected by magnetic particle during inspection is 10 mm.
1041
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Micrography by SEMDf - Void
Aspect of the magnetic particle result in the sample cut from the blade. The yellow scale is in mm.
76
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Aspect Before AnalysisDf - Crack
Linear indication in the sample, after metallographic preparation. The "cracking" is a casting defect.
65
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Kalling Etched MacroDf - Crack
Micrographic detail of the defect (void in the right side of the figure), as polished. In the left side it is the surface of the water blade and there are some non metalic inclusions in this region.
54
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Micrography by OMDf - Void
Micrographic detail non metalic inclusions in the region where there are casting defects. As polished.
47
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Micrography by OMDf - Non Metallic Inclusions
Blade microstructure. Tempered martensite, (probably) retained austenite and delta ferrite islands.
55
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Kalling Etched Micrography by OMDf - Delta Ferrite Islands
Blade microstructure. Previous austenite coarse grains.
46
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Kalling Etched Micrography by OMDf - Coarse Structure
Blade microstructure. Tempered martensite, (probably) retained austenite and delta ferrite islands.
47
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Kalling Etched Micrography by OMDf - Delta Ferrite Islands
Region of a casting void in the blade.
33
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Kalling Etched Micrography by OMDf - Void
Region of a casting void in the blade. As polished.
33
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Micrography by SEMDf - Void
Blade structure close to the region where the voids were detected.
40
VIEW
ML00017 / Apr.2017
Casting Defect in CA6NM
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Casting Defect
Cm - Kalling Etched Micrography by OMDf - Non Metallic Inclusions