Principal Features

STELLITE® alloy-like wear resistance and HASTELLOY® alloy-like corrosion resistance in a single, highly weldable material
ULTIMET® alloy (UNS R31233) provides a unique blend of properties. From a wear standpoint, it behaves like the STELLITE® alloys with lower carbon contents. From a corrosion standpoint, it possesses many of the attributes of the C-type and G-type HASTELLOY® materials, in particular outstanding resistance to chloride-induced pitting and crevice corrosion. Its mechanical and welding characteristics are much closer to those of the HASTELLOY® alloys than those of the STELLITE® alloys, whose low ductilities can be problematic.

While ULTIMET® alloy has been used successfully in the form of wrought products, its largest applications have involved weld overlays, made with solid wire consumables and arc-welding processes such as GMAW (MIG) and GTAW (TIG).

*Please contact our technical support team if you have technical questions about this alloy.

Nominal Composition

Weight %
Cobalt Balance
Chromium 26
Nickel 9
Molybdenum 5
Iron 3
Tungsten 2
Manganese 0.8
Silicon 0.3
Nitrogen 0.08
Carbon 0.06

Iso-Corrosion Diagrams

Each of these iso-corrosion diagrams was constructed using numerous corrosion rate values, generated at different acid concentrations and temperatures. The blue line represents those combinations of acid concentration and temperature at which a corrosion rate of 0.1 mm/y (4 mils per year) is expected, based on laboratory tests in reagent grade acids. Below the line, rates under 0.1 mm/y are expected. Similarly, the red line indicates the combinations of acid concentration and temperature at which a corrosion rate of 0.5 mm/y (20 mils per year) is expected. Above the line, rates over 0.5 mm/y are expected. Between the blue and red lines, corrosion rates are expected to fall between 0.1 and 0.5 mm/y.

Comparative 0.1 mm/y Line Plots

To compare the performance of ULTIMET® alloy with that of other materials, it is useful to plot the 0.1 mm/y lines. In the following graphs, the lines for ULTIMET® alloy are compared with those of two popular, austenitic stainless steels (316L and 254SMO), and two nickel alloys (625 and C-22®), in hydrochloric and sulfuric acids. The tests in hydrochloric acid were limited to a concentration of 20% (the azeotrope). At hydrochloric acid concentrations up to 15%, the performance of ULTIMET® alloy exceeds that of alloy 625, and in sulfuric acid, the performance of ULTIMET® alloy matches that of alloy 625 at many concentrations.

Selected Corrosion Data

Hydrochloric Acid

Conc. Wt.% 50°F 75°F 100°F 125°F 150°F 175°F 200°F 225°F Boiling
10°C 24°C 38°C 52°C 66°C 79°C 93°C 107°C
1 - - - - - - - - <0.05
1.5 - - - - - - - - -
2 - - - - - - - - -
2.5 - - - - <0.01 <0.01 <0.01 - 43.85
3 - - - - - - - - -
3.5 - - - - - - - - -
4 - - - - - - - - -
4.5 - - - - - - - - -
5 - - - - 0.01 5.75 - - -
7.5 - - - - - - - - -
10 - <0.01 0.16 0.80 1.74 - - - -
15 - 0.15 0.73 1.83 4.75 - - - -
20 - 0.17 0.56 1.04 2.58 - - - -

All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254.
Data are from Corrosion Laboratory Job 181-90.
All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.

Nitric Acid

Conc. Wt.% 50°F 75°F 100°F 125°F 150°F 175°F 200°F 225°F Boiling
10°C 24°C 38°C 52°C 66°C 79°C 93°C 107°C
10 - - - - - - - - <0.01
20 - - - - - - - - <0.01
30 - - - - - - - - 0.01
40 - - - - - - - - 0.03
50 - - - - - - - - 0.07
60 - - - - - - 0.03 - 0.12
65 - - - - - - 0.04 - 0.15
70 - - - - - - 0.06 - 0.18

All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254.
Data are from Corrosion Laboratory Job 182-90.
All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.

Phosphoric Acid

Conc. Wt.% 125°F 150°F 175°F 200°F 225°F 250°F Boiling
52°C 66°C 79°C 93°C 107°C 121°C
10 - - - -   - <0.01
20 - - - -   - 0.01
30 - - - -   - 0.01
40 - - - -   - 0.03
50 - - - <0.01 - - 0.14
60 - - - 0.01 - 0.01 0.25
70 - - - 0.01 0.01 0.02 0.46
80 - - - 0.01 0.07 0.55 10.95
85 - - - 0.01 0.07 0.57 30.58

All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254.
Data are from Corrosion Laboratory Job 183-90.
All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.

Sulfuric Acid

Conc. Wt.% 75°F 100°F 125°F 150°F 175°F 200°F 225°F 250°F 275°F 300°F 350°F Boiling
24°C 38°C 52°C 66°C 79°C 93°C 107°C 121°C 135°C 149°C 177°C
1 - - - - - - - - - - - 0.13
2 - - - - - <0.01 - - - - - 0.27
3 - - - - - - - - - - - -
4 - - - - - - - - - - - -
5 - - - <0.01 - 0.01 - - - - - 1.26
10 - - - - - 0.43 - - - - - 1.92
20 - - - <0.01 0.01 1.83 - - - - - 4.48
30 - - - <0.01 1.36 3.58 - - - - - 10.54
40 - <0.01 <0.01 0.29 2.25 - - - - - - 20.94
50 - <0.01 - 0.96 - - - - - - - -
60 - <0.01 <0.01 1.48 - - - - - - - -
65 - - 0.63 - - - - - - - - -
70 - <0.01 0.55 - - - - - - - - -
80 - <0.01 1.02 1.64 - - - - - - - -
85 - 0.03 - - - - - - - - - -
90 <0.01 0.26 1.68 - - - - - - - - -
96 <0.01 0.21 1.76 2.24 - - - - - - - -

All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254.
Data are from Corrosion Laboratory Jobs 159-90 and 8-91.
All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.

Reagent Grade Solutions, mm/y

Chemical Conc. wt. % 100°F 125°F 150°F 175°F 200°F Boiling
38°C 52°C 60°C 79°C 93°C
Acetic Acid 99 - - - - - <0.01
Hydrochloric Acid 1 - - - - - 0.05
2.5 - - <0.01 <0.01 <0.01 43.85
5 - - 0.01 - - -
10 0.16 0.80 1.74 - - -
15 0.73 1.83 - - - -
20 0.56 1.04 - - - -
Nitric Acid 10 - - - - - <0.01
20 - - - - - <0.01
30 - - - - - 0.01
40 - - - - - 0.03
50 - - - - - 0.07
60 - - - - 0.03 0.12
65 - - - - 0.04 0.15
70 - - - - 0.06 0.18
Phosphoric Acid 10 - - - - - <0.01
20 - - - - - 0.01
30 - - - - - 0.01
40 - - - - - 0.03
50 - - - - <0.01 0.14
60 - - - - 0.01 0.24
70 - - - - 0.01 0.45
80 - - - - 0.01 10.92
85 - - - - 0.01 30.58
Sulfuric Acid 1 - - - - - 0.13
2 - - - - <0.01 0.27
5 - - <0.01 - 0.01 1.26
10 - - - - 0.43 1.92
20 - - <0.01 0.01 1.83 -
30 - - <0.01 1.36 - -
40 <0.01 <0.01 0.29 2.25 - -
50 <0.01 - 0.96 - - -
60 <0.01 <0.01 1.48 - - -
70 <0.01 0.55 - - - -
80 <0.01 1.02 - - - -
90 0.26 1.68 - - - -
96 0.21 1.76 - - - -

Galling Resistance

Erosion Resistance

Abrasion Wear

AWM = All weld metal WO = Weld overlay WRT = Wrought

Resistance to Pitting and Crevice Corrosion

ULTIMET® alloy exhibits very high resistance to chloride-induced pitting and crevice attack, forms of corrosion to which the austenitic stainless steels are particularly prone.

To assess the pitting resistance of ULTIMET® alloy relative to other corrosion-resistant materials, it has been subjected to tests in Green Death (11.5% H2SO4 + 1.2% HCl + 1% FeCl3 + 1% CuCl2). Experiments wereperformed at various temperatures (in increments of 5°C) to determine the lowest temperature at which pitting occurs in a 24 h test period (the so-called Critical Pitting Temperature for Green Death). The results were as follows:

Alloy Critical Pitting Temperature
- °F °C
ULTIMET® 248 120
C-22® 248 120
C-276 230 110
625 167 75
6B 113 45
316L 77 25

Resistance to Stress Corrosion Cracking

Sulfide Stress Cracking

  • Wrought ULTIMET alloy has been tested according to NACE TM0177, which defines sulfide stress cracking as a room temperature phenomenon, resulting from hydrogen embrittlement.
  • The TM0177 tests involved 5% NaCl + 0.5% glacial acetic acid, saturated with H2S, proof-ring apparatus, and samples coupled to carbon steel and stressed to the point of yield.
  • ULTIMET alloy was able to withstand these conditions, both annealed and cold-reduced (15%), indicating good resistance to hydrogen embrittlement.

H2S – Induced Stress Corrosion Cracking

  • Cracking at elevated temperatures in environments containing H2S is defined as a form of stress corrosion cracking.
  • Wrought ULTIMET alloy has been tested in 20% NaCl + 0.517 MPa (75 psi) H2S + 4.83 MPa (700 psi) CO2, with and without 0.5 g/l sulfur, at 121°C and 177°C; the tests were conducted according to the recommendations of ASTM Standard G 39, the fixtures being made of ULTIMET alloy, to prevent galvanic effects.
  • Like other materials, ULTIMET alloy was prone to cracking in the cold-reduced condition, but resistant to H2S-induced stress corrosion cracking in the annealed condition, at these temperatures.

Resistance to Seawater Crevice Corrosion

Seawater is probably the most common aqueous salt solution. Not only is it encountered in marine transportation and offshore oil rigs, but it is also used as a coolant in coastal facilities. Listed are data generated as part of a U.S. Navy study at the LaQue Laboratories in Wrightsville Beach, North Carolina (and published by D.M. Aylor et al, Paper No. 329, CORROSION 99, NACE International, 1999). Crevice tests were performed in both still (quiescent) and flowing seawater, at 29°C, plus or minus 3°C. Two samples (A & B) of each alloy were tested in still water for 180 days, and likewise in flowing water. Each sample contained two possible crevice sites. The results indicate that ULTIMET® alloy is even more resistant to crevice corrosion in seawater than C-276 alloy.

Alloy Quiescent Flowing
- No. of Sites Attacked Maximum Depth of Attack, mm No. of Sites Attacked Maximum Depth of Attack, mm
316L A:2, B:2 A:1.33, B:2.27 A:2, B:2 A:0.48, B:0.15
254SMO A:2, B:2 A:0.76, B:1.73 A:2, B:2 A:0.01, B:<0.01
625 A:2, B:2 A:0.18, B:0.04 A:2, B:2 A:<0.01, B:<0.01
C-276 A:1, B:1 A:0.10, B:0.13 A:0, B:0 A:0, B:0
C-22® A:0, B:0 A:0, B:0 A:0, B:0 A:0, B:0
ULTIMET® A:0, B:0 A:0, B:0 A:0, B:0 A:0, B:0

Corrosion Resistance of Welds

One of the most important product forms of ULTIMET® alloy is welding wire, since many applications involve ULTIMET® weld overlays. These overlays are, of course, subject to dilution from the substrate material, often a steel or stainless steel. To provide some idea of the influence of dilution upon the corrosion resistance of ULTIMET® weld overlays, a study was undertaken whereby pre-diluted consumables were made by the aspiration casting process, and all-weld-metal (AWM) samples made by deposition on chilled copper blocks. Thus, it was possible to conduct regular (rather than one-sided) corrosion tests in acid solutions on homogeneous samples, diluted with specific substrate materials.

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ULTIMET® Alloy Corrosion Rate, mm/y
3% HCl, 66°C (150°F)
Boiling 65% HNO3
Boiling 2% H2SO4
Undiluted 0.68 0.15 0.41
Diluted with 9.1%/G10400 1.80 0.30 0.69
Diluted with 9.1%/S31603 1.42 0.25 0.58
Diluted with 16.7%/G10400 2.13 0.30 0.84
Diluted with 16.7%/S31603 2.08 0.23 0.48

Physical Properties

Physical Property British Units Metric Units
Density RT
0.306 lb/in.3
RT
8.47 g/cm.3
Electrical Resistivity RT 34.3 µohm.in RT 0.87 µohm.m
200°F 35.2 µohm.in 100°C 0.89 µohm.m
400°F 36.7 µohm.in 200°C 0.93 µohm.m
600°F 38.2 µohm.in 300°C 0.96 µohm.m
800°F 39.6 µohm.in 400°C 1.00 µohm.m
1000°F 40.9 µohm.in 500°C 1.03 µohm.m
- - 600°C 1.05 µohm.m
Thermal Conductivity RT
87 Btu.in/h.ft2.°F
RT 12.3 W/m.°C
200°F
95 Btu.in/h.ft2.°F
100°C 13.8 W/m.°C
400°F
109 Btu.in/h.ft2.°F
200°C 15.6 W/m.°C
600°F
123 Btu.in/h.ft2.°F
300°C 17.5 W/m.°C
800°F
138 Btu.in/h.ft2.°F
400°C 19.4 W/m.°C
1000°F
155 Btu.in/h.ft2.°F
500°C 21.5 W/m.°C
- - 600°C 23.9 W/m.°C
Thermal Diffusivity RT
0.005 in.2/s
RT
0.033 x 10-6cm2/s
200°F
0.005 in.2/s
100°C
0.035 x 10-6cm2/s
400°F
0.006 in.2/s
200°C
0.038 x 10-6cm2/s
600°F
0.007 in.2/s
300°C
0.042 x 10-6cm2/s
800°F
0.007 in.2/s
400°C
0.045 x 10-6cm2/s
1000°F
0.007 in.2/s
500°C
0.047 x 10-6cm2/s
- - 600°C
0.050 x 10-6cm2/s
Mean Coefficient of Thermal Expansion 78-200°F 7.2 µin/in.°F 26-100°C 13.0 µm/m.°C
78-400°F 7.5 µin/in.°F 26-200°C 13.4 µm/m.°C
78-600°F 7.8 µin/in.°F 26-300°C 14.0 µm/m.°C
78-800°F 8.0 µin/in.°F 26-400°C 14.3 µm/m.°C
78-1000°F 8.2 µin/in.°F 26-500°C 14.8 µm/m.°C
78-1200°F 8.4 µin/in.°F 26-600°C 15.0 µm/m.°C
78-1400°F 8.8 µin/in.°F 26-700°C 15.4 µm/m.°C
78-1600°F 9.1 µin/in.°F 26-800°C 16.1 µm/m.°C
Specific Heat 100°F 0.110 Btu/lb.°F RT 456 J/kg.°C
200°F 0.112 Btu/lb.°F 100°C 470 J/kg.°C
400°F 0.116 Btu/lb.°F 200°C 482 J/kg.°C
600°F 0.121 Btu/lb.°F 300°C 504 J/kg.°C
800°F 0.127 Btu/lb.°F 400°C 525 J/kg.°C
1000°F 0.133 Btu/lb.°F 500°C 545 J/kg.°C
- - 600°C 573 J/kg.°C
Dynamic Modulus of Elasticity RT
33.2 X 106psi
RT 229 GPa
200°F
32.6 X 106psi
100°C 224 GPa
400°F
31.2 X 106psi
200°C 216 GPa
600°F
29.9 X 106psi
300°C 208 GPa
800°F
28.6 X 106psi
400°C 199 GPa
1000°F
27.4 X 106psi
500°C 192 GPa
1200°F
26.1 X 106psi
600°C 184 GPa
Melting Range 2430-2470°F - 1332-1354°C -

RT= Room Temperature

Impact Strength

These impact strengths were generated using Charpy V-notch samples, machined from mill annealed plate of thickness 12.7 mm (0.5 in).

Test Temperature Impact Strength
°F °C ft-lbf J
RT RT 130 176
-40 -40 125 169
-80 -62 119 161
-320 -196 68 92

RT= Room Temperature

Tensile Strength and Elongation

Form Test Temperature Thickness/ Bar Diameter 0.2% Offset Yield Strength Ultimate Tensile Strength Elongation
°F °C in mm ksi MPa ksi Mpa %
Sheet RT RT 0.063 1.6 72 496 138 951 42
Sheet 200 93 0.063 1.6 58 400 135 931 50
Sheet 400 204 0.063 1.6 45 310 134 924 62
Sheet 600 316 0.063 1.6 43 296 130 896 75
Sheet 800 427 0.063 1.6 41 283 120 827 76
Plate RT RT 0.25-1.5 6.4-38.1 79 545 148 1020 36
Plate 200 93 0.25-1.5 6.4-38.1 70 483 143 986 40
Plate 400 204 0.25-1.5 6.4-38.1 55 379 143 986 61
Plate 600 316 0.25-1.5 6.4-38.1 48 331 138 951 70
Plate 800 427 0.25-1.5 6.4-38.1 45 310 133 917 70
Plate 1000 538 0.25-1.5 6.4-38.1 38 262 125 862 70
Plate 1200 649 0.25-1.5 6.4-38.1 37 255 99 683 66
Plate 1400 790 0.25-1.5 6.4-38.1 39 269 76 524 70
Plate 1600 871 0.25-1.5 6.4-38.1 28 193 51 352 77
Plate 1800 982 0.25-1.5 6.4-38.1 16 110 31 214 100
Bar RT RT 0.5-2.0 12.7-50.8 76 524 147 1014 38
Bar 200 93 0.5-2.0 12.7-50.8 70 483 140 965 49
Bar 400 204 0.5-2.0 12.7-50.8 52 359 140 965 66
Bar 600 316 0.5-2.0 12.7-50.8 44 303 132 910 77
Bar 800 427 0.5-2.0 12.7-50.8 43 296 131 903 84
Bar 1000 538 0.5-2.0 12.7-50.8 40 276 114 793 79

RT= Room Temperature

Hardness

In the annealed condition, ULTIMET alloy is not very hard. However, it has a high work-hardening rate, and even stretching of sheets and flattening of plates during mill processing can increase its hardness. The hardnesses in this table were measured on mill sheets, and indicate how rapidly the alloy hardens upon cold working.

Condition Hardness, HRC
Mill Annealed 30
10% Cold-Work 40
20% Cold-Worked 43
40% Cold-Worked 49

HRC = Hardness Rockwell “C”.

Welding and Fabrication

ULTIMET® alloy is very amenable to the Gas Metal Arc (GMA/MIG), Gas Tungsten Arc (GTA/TIG), and Shielded Metal Arc (SMA/Stick) welding processes. Matching filler metals (i.e. spools, reels, coils, and cut straight lengths of solid wire, and coated electrodes) are available for these processes. Guidelines for weld surfacing with ULTIMET® alloy are detailed in a separate Haynes International document “ULTIMET® Weld Overlay Guidelines“. Other arc processes have been used to weld ULTIMET® alloy; for more information on consumable availability for these other processes, please consult Haynes International.

Wrought products of ULTIMET® alloy are supplied in the Mill Annealed (MA) condition, unless otherwise specified. This solution annealing procedure has been designed to optimize the alloy’s corrosion resistance and ductility. Following all hot forming operations, the material should be re-annealed, to restore optimum properties. The alloy should also be re-annealed after any cold forming operations that result in an outer fiber elongation of 7% or more. The annealing temperature for ULTIMET® alloy is 1177°C (2150°F), and water quenching is advised (rapid air cooling is feasible with structures thinner than 10 mm (0.375 in). A hold time at the annealing temperature of 10 to 30 minutes is recommended, depending on the thickness of the structure (thicker structures need the full 30 minutes).

ULTIMET® alloy can be hot worked and cold-worked. However, it is very strong, and work-hardens rapidly during cold-working. The alloy may therefore require frequent, intermediate anneals, if cold-working is employed. Please consult Haynes International for more details.

While cold-work does not usually affect the resistance of ULTIMET® alloy to general corrosion, and to chloride-induced pitting and crevice attack, it can affect resistance to stress corrosion cracking. For optimum corrosion performance, therefore, the re-annealing of cold-worked parts (following an outer fiber elongation of 7% or more) is important.

Welding Data

Typical Transverse Tensile Data, Weldments

FormWeld TypeTest Temperature0.2% Offset Yield StrengthUltimate Tensile StrengthElongation

Form Weld Type Test Temperature 0.2% Offset Yield Strength Ultimate Tensile Strength Elongation
- - °F °C ksi* ksi* %
Plate 1/2 in. (12.7mm) thick GTAW RT RT 89 127 11
GMAW (Short) RT RT 98 121 6
500 260 65 121 19
1000 538 53 114 28
GMAW (Spray) RT RT 93 133 11
500 260 67 121 19
1000 5.38 65 113 30
SMAW RT RT 97 135 9
Plate 3/4 (19.1mm) thick GMAW (Short) RT RT 86 123 10
500 260 62 116 20
1000 538 45 98 26
GMAW (Spray) RT RT 90 136 15
500 260 64 121 23
1000 538 50 113 32
SMAW RT RT 87 130 13
1000 538 48 109 32

*ksi can be converted to MPa (megapascals) by multiplying by 6.895.

Typical Tensile Data, All-Weld Metal

Weld Type Test Temperature 0.2% Offset Yield Strength Ultimate Tensile Strength Elongation
- °F °C ksi* ksi* %
GTAW RT - 95 133 10
GMAW (Short) RT - 89 132 17
GMAW (Spray) RT - 85 123 18
SMAW RT - 93 13 16
1000 - 61 100 31

Typical Impact Strength, Weldments

Weld Type V-Notch Impact Strength Room Temperature
- ft.-lb. J
GTAW 94 127
SMAW 42 57

Typical Bend Test Data, Welded Plate

Weld Type Face Bend Side Bend
- 2T 3T 2T 3T
GMAW (Short) Failed Passed Failed Passed
GMAW (Spray) Failed Passed Failed Passed
SMAW - Passed - -

Duplicate specimens, 3/4 in. (19.10 mm) thick. Tested using AWS Specification 5.11 as a guide.

Specifications and Codes

Specifications

ULTIMET® (R31233)
Sheet, Plate & Strip SB818/B818
Billet, Rod & Bar B815
Coated Electrodes -
Bare Welding Rods & Wire -
Seamless Pipe & Tube -
Welded Pipe & Tube -
Fittings -
Forgings -
DIN No. 2.4681CoCr26Ni9Mo5W
TÜV -
Others NACE MR0175/MR0103ISO 15156

Codes

ULTIMET® (R31233)
ASME Section l -
Section lll Class 1 -
Class 2 -
Class 3 -
Section Vlll Div. 1 800°F (427°C)
Div. 2 -
Section Xll -
B16.5 -
B16.34 -
B31.1 -
B31.3 -
VdTÜV (doc #) -

1Plate, Sheet, Bar

Disclaimer

Haynes International makes all reasonable efforts to ensure the accuracy and correctness of the data displayed on this site but makes no representations or warranties as to the data’s accuracy, correctness or reliability. All data are for general information only and not for providing design advice. Alloy properties disclosed here are based on work conducted principally by Haynes International, Inc. and occasionally supplemented by information from the open literature and, as such, are indicative only of the results of such tests and should not be considered guaranteed maximums or minimums.  It is the responsibility of the user to test specific alloys under actual service conditions to determine their suitability for a particular purpose.

For specific concentrations of elements present in a particular product and a discussion of the potential health affects thereof, refer to the Safety Data Sheets supplied by Haynes International, Inc.  All trademarks are owned by Haynes International, Inc., unless otherwise indicated.

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