Properties and Performance of a
High Chromium Nickel Alloy
Filler Metal: 52iFiller Metal: 52iDouglas G. Baldrey1, Catherine M. Brown2, James B. Burns1, Thomas E.
Capobianco1, Heather M. Mohr1, David S. Morton1, Tyler E. Moss1, John V. Mullen1, Larry Paul3, Elaine West1, and
George A. Young1
1Bechtel Marine Propulsion Corporation, Knolls Atomic Power Laboratory, Niskayuna, NY 123092Bechtel Marine Propulsion Corporation Bettis Atomic Power Laboratory, West Mifflin, PA 15122
3Outokumpu VDM USA LLC, Richburg, SC 29706
Scope of Work
• Physical and Thermal Properties
• Elastic and Mechanical Properties
• Weldability
• Environmentally Assisted Cracking• Environmentally Assisted Cracking
– Low Temperature Crack Propagation
– Corrosion Fatigue in Primary Water
– Primary Water Stress Corrosion
• Metallurgical Stability
2
Materials and Welding Processes• 3 Heats of material assessed
• Property data primarily on A-GTAW
– Weld pads and v-grooves
• Limited testing of shielded-metal-arc welds
• Weldability testing also on M-GTAW and GMAW• Weldability testing also on M-GTAW and GMAWTable I. Comparison of the Composition of Each Heat of Material in wt.%
Heat Cr Fe Nb Mn Ti S P C N
MLTS-2 26.83 3.05 2.51 3.19 0.17 0.0014 0.003 0.032 0.009
187775 26.98 2.55 2.58 3.04 0.37 0.0010 0.002 0.040 0.039
126373 26.97 2.55 2.29 2.97 0.30 0.0010 0.003 0.043 0.017
Specification* 26.0
28.0
2.0
3.0
2.2
2.4
2.5
3.5
0.2
0.4 <0.002 <0.008
0.03
0.05
0.015
0.040
*Most recent values based on current testing
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Physical PropertiesDensity, CTE, specific heat, conductivity are typical of Ni-Cr alloys
4
Elastic Properties<100> weld texture influences modulus
5
Mechanical Properties (1)• Typical tensile
properties given
from multiple
heats and tests
• Room T YS~65
ksi, UTS ~95 ksi,
80
90
100
70
80
90
100
110
% E
lon
ga
tio
n a
nd
Re
du
ctio
n i
n A
rea
Str
en
gth
(k
si)
Typical Tensile PropertiesEffect of Stress Relief: 'L' GTAW
UTS
30 hrs / 1050°F
As Welded
ksi, UTS ~95 ksi,
>50% RA and
~40% EL
• No detrimental
effect of PWHT
(1050°F / 30
hours)6
30
40
50
60
70
0
10
20
30
40
50
60
70
0 100 200 300 400 500 600 700 800 900
% E
lon
ga
tio
n a
nd
Re
du
ctio
n i
n A
rea
Str
en
gth
(k
si)
Temperature (oF)
YS
%RA
%El
30 hrs / 1050°F
Mechanical Properties (2)GTAW and SMAW properties comparable. Little effect
of orientation with exception of lower ‘T’ %Elongation
80
90
100
80
90
100
110
% E
lon
ga
tio
n a
nd
Re
du
ctio
n i
n A
rea
As-Welded 'L' Tensile PropertiesEffect of Process: GTAW vs. SMAW
UTS
SMAW
GTAW80
90
100
80
90
100
110
% E
lon
ga
tio
n a
nd
Re
du
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n i
n A
rea
Typical Tensile PropertiesEffect of Orientation: GTAW
UTS
T
30
40
50
60
70
0
10
20
30
40
50
60
70
0 100 200 300 400 500 600 700 800 900
% E
lon
ga
tio
n a
nd
Re
du
ctio
n i
n A
rea
Str
en
gth
(k
si)
Temperature (oF)
YS
%RA
%El
GTAW
7
20
30
40
50
60
70
0
10
20
30
40
50
60
70
0 100 200 300 400 500 600 700 800 900
% E
lon
ga
tio
n a
nd
Re
du
ctio
n i
n A
rea
Str
en
gth
(k
si)
Temperature (oF)
YSYS
%RA
%El
T
L
Weldability (1)Good resistance to solidification cracking, Spec limit on
Nb changed to improve on Heat 187775
8
Weldability (2)
EN52i data (red bars)show good resistance toDDC and solidificationcracking relative to otherNi-Cr filler metals
# of
cracks
# of
cracks# of
9
# of
cracks
# of
cracks
Weldability (3)Vendor experience consistently good. Comparable to ‘good
welding’ EN82H. GTAW, SMAW, GMAW.
Table III. Summary of Industrial Experience with EN52i
User Process Comments
B&W (Barberton)
Automatic GMAW and manual
GTAW cladding and groove EN52i can directly replace
EN82H B&W (Barberton) GTAW cladding and groove
welds EN82H
B&W (Mount Vernon) Automatic GTAW cladding
EN52i has similar weldability,
bead texture, bead tie-in, and
puddle control as EN82H
Hamill Manufacturing Manual GTAW for dissimilar
metal weld joints
EN52i has the same welding
characteristics as EN82H
Electric Boat GTAW pipe welds with Alloys
600 and 690
Excellent flow and tie-in with
EN52i
Newport News Shipyard GTAW pipe welds with Alloys
600 and 690
Excellent flow and tie-in with
EN52i
Arc Applications GTAW steam generator tube
plug development
No significant difference
between EN52i and EN82H
10
LTCP ResistanceVery high toughness in air. LTCP resistance ≥ EN82H
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Corrosion Fatigue in Primary WaterComparable to A690 & EN82H, benefit relative to 304L SS
12
Primary Water SCC (1)At Least 50X Benefit Relative to EN82H
13
Primary Water SCC (2)Samples only show pockets of SCC & cracks do not extend more
than 1 grain. Methodology to report CGR as 100% engagement
with no consideration of grain to grain incubation bias EN52i
rates high � 50X benefit is conservative. See paper by Moss et
al., these Proceedings
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Primary Water SCC (3)Composite material testing confirms >50X benefit, no increase in
growth after 24 months(!), cracks slow/arrest in 1st 52i bead
15
680°F
KI=30 ksi√in
Metallurgical StabilitySeveral Ni-Cr Alloys could be susceptible to long range
ordering. Testing on 52i to date (3000 hours) shows no
evidence of LRO.
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Conclusions (1)• Physical properties consistent with other nickel-chromium
weld filler metals.
• Typical of most FCC ‘austenitic’ weld filler metals, EN52i welds display significant <100> type texture. Consequently Young’s modulus can display anisotropy.
• The tensile strength of EN52i is moderate (~65 ksi) and ductility is high (%Elongation and %RA ≥ 30%).ductility is high (%Elongation and %RA ≥ 30%).– The tensile properties are insensitive to typical post weld heat
treatments (~1050°F / 30 hours)
– Tensile properties are comparable between GTAW and SMAW
– Little effect of L vs. T orientation
• Both in-house and vendor experience with EN52i indicates very good weldability. Vendor experience confirms that welding parameters developed for EN82H can be directly used for EN52i.
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Conclusions (2)• High fracture toughness in air and more resistant to Low
Temperature Crack Propagation (LTCP) than EN82H.
• Corrosion fatigue testing shows crack growth rates consistent with Alloy 690 & EN82H and superior to 304L stainless steel.
• The primary water SCC resistance of EN52i is far superior to EN82H. Aggressive testing, 680°F near Ni/NiO stability indicate ≥ 50X slower rates in EN52i relative to EN82H. – This benefit is likely conservative, based on adjusting the crack – This benefit is likely conservative, based on adjusting the crack
growth to 100% engagement and does not account for an incubation time for cracking to propagate into new grains.
– Composite specimen testing confirms this benefit as shown by SCC in the E-182 / EN52i samples markedly slowing their rate or possibly arresting in the first weld bead diluted with EN52i.
• Testing between 631-878°F (333-470°C) for times up to 3,000 hours indicated good metallurgical stability with no hardening that would suggest susceptibility to long range ordering.
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