LASER CLADDING OF SHIP COMPONENTS MICROSTRUCTURAL EVALUATION

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LASER CLADDING OF SHIP COMPONENTS
MICROSTRUCTURAL EVALUATION

• 17 January 2003
• BIJAYA ADAK
• DR. PHILIP NASH

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Overview

• Microstructural Evaluation of Laser Cladded
  Sample
• (Provided by IITRI)
• Brief Overview of HY100 and Propeller Bronze
• Paper Studies
• Laser Cladding of Low Carbon Steel
• Laser Cladding of Nickel Aluminum Bronze
• Web Sites of Interest on Laser Cladding and
  References

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Microstructural Evaluation of Laser Cladded
Sample (Provided by IITRI)

• Sample provided by IITRI is under evaluation.
• Plan for
• Optical Microscope
• Sample prepared. Etching and evaluation planned
  for next week.
• XRD
• Sample was evaluated.
• The structure appears to be either Nickel solid
  solution with Ni3Al or just Ni3Al.
• Planned to evaluate the surface of the clad on
  SEM (no grinding and polishing) to see if there
  are solidification porosity in the
  inter-dendritic regions.
• SEM
• Sample was evaluated.

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Dr. Nashs Comments on XRD results
The structure appears to be either Nickel solid
solution with Ni3Al or just Ni3Al. There is a
very strong (100) texture which is typical of
rapidly solidified Ni-base alloys parallel to the
dendrite growth direction. This leads to an
unusually high (200) peak and also in this case
(100) peak. Remember that the (100) peak is a
superlattice line due to ordering. I would like
to see the surface of the clad in the SEM (no
grinding and polishing). If there are (100)
dendrites we may be able to see solidification
porosity in the interdendritic regions. The peaks
you have can be roughly indexed as (100), (111),
(200), (220), (300), (311) and (400) . More
accurate indexing requires accurate peak angles
which you can get from the software. It is
possible that the last peak is not (400) and I
think it would be worth looking from 110 to 135
degrees if that is possible with a slow scan rate
to see if there is another peak with good
intensity. This may yield information as to
whether there is an ordered and disordered phase
present (you should see peak splitting). Looking
at the data you have there is no evidence of peak
splitting but this becomes more pronounced at
higher angles.
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SEM Micrography of Clad Surface
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• HY 100 Steel
• Composition
• C 0.17
• Mn 0.3
• Cu 0.13
• Si 0.22
• Ni 2.35
• Cr 1.32
• Sn 0.013
• Mo 0.25
• Fe Balance
• Mechanical Property
• Highly Ductile
• Medium Strength
• Very High Fracture Toughness

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• Propeller Bronze (CDA 958 )
• Composition
• Cu 81
• Ni 5
• Al 9
• Fe 4
• Mechanical Property
• High strength
• Ductile
• Highly Corrosion and cavitation Resistant
• Very Tough
• Application
• CDA 958 is primarily used for (quiescent) salt
  water
• applications and common pump components and for
• butterfly valves for the Navy.

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PAPER STUDIES
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Laser Cladding of Low Carbon Steel

• Substrate Low Carbon Steel (lt0.2 C)
• -Ductile
• -Low Cost
• Clad Material Hadfield Steel (1.2 C, 12 Mn)
• -Extremely tough
• -Wear and shock resistant
• -Very sensitive to plastic deformation
• The Cladded Material combines the advantages of
  Hadfield Steel and properties of low carbon
  steel.
• Clad Material Delivery System Powder Injection
• Laser System Used CO2 Laser (1-3 kw Power)

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Results The optimum parameters were Power
1600 W Speed 1cm/sec Feed Rate 8gm/min Dia.
Of the beam 2.5mm The Clad Region can be
divided into three parts a) Unaffected
Substrate b) HAZ- Carbon dissolution occurred
during the austenization. Due to self-
quenching, Martensite was formed from Austenite
with a non-uniform distribution. Formation of
Martensite was favoured near the melting
zone. c) Cladding - Irregularly oriented
dendritic structure. Mainly Austenitic phase
with a very little amount of Ferrite.
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Shortcoming Substrate (Low Carbon Steel) is
relatively soft as compared to the Clad Material
(HF Steel). Due to the inhomogeneous plastic
deformation during Cold Working, numerous no. of
cracks were observed on the Cladded Surface which
resulted in Orange Peel Effect.
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Laser Cladding of Nickel Aluminum Bronze

• Substrate UNS C95000 (80.3Cu, 8.75Al, 4.8Ni,
  4.4Fe, 1.4Mn,)
• Clad Material (Wire) ErCuNiAl (80.8Cu, 9Al,
  4.6Ni, 4Fe, 1 Mn,)
• Objective
• Determination of the effect of processing
  parameter (heat input) on the microstructure and
  properties of Nickel Aluminum Bronze .
• Laser System Used CO2 Laser (5 kw Power)
• Only the deposited material and the reheated part
  of the deposited material were investigated. HAZ
  was not considered in the investigation.

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• Microstructural Evaluation
• Etchant composition
• - 5gm Fecl3
• -15 ml Hcl
• -60 ml Ethanol
• Microstructure Consisted of
• - Martensite
• - Ferrite
• Grain Boundary Allotriomorphs
• Widmanstattens a sideplates
• Inter-granular Widmanstattens a Precipitates
• Lathe Martensite

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• Deposit Microstructure
• At the lowest heat input (42.5 J/mm), fully
  Martensitic microstructure was found. As the heat
  input increases, amount of Ferrite increases.
  Depending upon the heat input the morphology of
  Ferrite was different.
• Reheated Zone Microstructure
• Microstructure consisted of mixture of
  Martensite and Ferrite (in different
  morphologies). Coarseness increases with
  increase in heat input. At 390 J/mm and 595 J/mm
  a clear equi-axed zone was observed adjacent to
  the fusion line.

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• Resultant Properties
• Corrosion
• Laser Cladded sample with 68J/mm heat input
  showed the highest corrosion resistance and
  incubation period. As the heat input increases,
  the corrosion resistance decreases but it did not
  affect the incubation period.
• Stress Corrosion Cracking property was not
  affected by the heat input.
• Martensite was attacked more than the Grain
  Boundary Allotriomorphs Ferrite and
  Widmanstattens a sideplates during the long term
  corrosion experiment.
• Bend Test
• Ductility of Clad Material was much less than
  the Unclad Material. Cracks on the Clad Material
  were audible and more severe than the unclad
  specimen.
• Hardness
• Deposit Highest hardness level (HV of 540)
  achieved at 62.5 J/mm due to secondary
  precipitation hardening effect.

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• Contn
• It was mentioned that using Helium as a shielding
  gas allowed for larger amount of material
  deposition compared to Argon.

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Web Sites of Interest on Laser Cladding

• Fraunhofer Institute for Lasertechnology
  ILThttp//www.ilt.fhg.de/index_e.html
• Applications and Benefits of Direct Diode Laser
  Nuvonyx Inc.
• http//www.nuvonyx.com/slide20show/sld001.htm

References

• Hadfield Steel Coatings on Low Carbon Steel by
  Laser Cladding, Pelletier.J.M et. al , Materials
  Science and Engineering A202 (1995), pp. 142-147
• The Effect of heat input on the Microstructure
  and Properties of Nickel Aluminum Bronze Laser
  Clad with a consumable of Composition
  Cu-9.0Al-4.6Ni-3.9Fe-1.2Mn, Hyatt.C.V,
  Magee.K.H, Betancourt.T, Metallurgical and
  Materials Transactions A, Vol 29A, June 1998, pp.
  1677-1690