Liburdi Engineering Limited

Liburdi Engineering Ltd Liburdi Turbine Services Inc Liburdi Automation Inc Liburdi Dimetrics Corp

Dundas, Ontario Davidson, North Carolina St Petersburg, Russia

Liburdi Group of Companies

Dundas, Ontario Canada

Davidson, NC, USA

2Turbomachinery

Conference Houston, TX September 13-17, 2009

PowerGen

Conference Las Vegas, NV December 7-10, 2009

3Superalloys

4Typical Gas Turbine Component Materials

Turbine Stationary300SS, 400SSN-155, M509, HS-188,L605X-40, X-45, FSX-414, ECY-768IN738, R80, GTD222, GTD444

Turbine Rotating

Waspalloy, U-500, U520, U700, U710, U720, INX750, IN738, Rene80, GTD111, M247, M002,PWA1483, CMSX4, ReneN5

Piping, tubing, valves, etc.Steel

Compressor CasingsGrey Cast IronCarbon Steel

Turbine ShellsDuctile Cast Iron

Compressor Wheels/DisksNi-Cr-MO-VForging

Turbine Wheels/DiscsNi-Cr-MO-V Steel Cr-Mo-V Forging12Cr StainlessDiscalloyA286IN718

CompressorSome 300SS403, 410, 422, 450 StainlessIN718Ti64 titanium

Combustor300SSHastelloy-X, RA-33 L-605IN-600, IN-617Nimonic 75, Nimonic 263Haynes 230

5SUPERALLOYS

1. Definition and Properties2. Strengthening Mechanisms

- Solid Solution Hardening- Precipitation Hardening and Heat Treatment- Grain Boundary Hardening and Control

3. Surface Stability: Oxidation and Hot Corrosion

6SUPERALLOY DEFINITION

Superalloys have remarkable mechanical strength at high temperatures -- up to 80% of their incipient melting point.

Superalloys exhibit the highest surface stability in air at elevated temperatures of engineering alloys.

Superalloys are also exotic as they can contain up to 12 elements And they can have as many elements specifically excluded.

7ALLOY PROPERTIES

Metals and their alloys have varying strength andoxidation resistance (and cost)

Alloys used for Turbine Blades/Buckets

8MECHANICAL PROPERTIES

Fe/Ni-based superalloys are economical, high strength forging alloys for low and intermediate temperatures

Ni-based superalloys can withstand high creep stresses at intermediate and high temperatures

Co-based superalloy are castable, weldable, and useful at very high temperature and corrosive environments

9Compositions and Properties - Nickel Based Alloys

Sheet alloys like Hasteloy X have low Aluminum + Titanium content have excellent formability

Forged alloys like Udimet 520, Nimonic105, X750 have a moderate Aluminum + Titanium content, have good mechanical properties but are forgeable. Used for intermediate-temperature buckets.

Cast alloys like CMSX, GTD111, IN738, MM247 have a high Aluminum + Titanium content, have excellent mechanical properties at elevated temperature and are used for the highest temperature blades.

10

SUPERALLOY PROPERTIES

Excellent mechanical properties in the service temperature and stress range that gas turbine blades operate in, even after prolonged service

Excellent creep strength

Useful mechanical strength

Good fatigue and thermal fatigue properties

Adequate ductility and toughness (low crack growth rates)

Useful thermal expansion characteristics

Excellent resistance to oxidation and corrosion

Alloy additions form self-healing protective scales

Fabricability (forging, casting, welding, machining, coating)

11

SUPERALLOY DESIGN

Solvent can be cobalt, iron or nickel (usually a mixture of nickel and cobalt)

Oxidation protection provided by aluminum & chromium

Solutes, molybdenum, niobium, rhenium, tantalum, tungsten

Precipitation formers: aluminum, titanium, niobium

Grain strengtheners: carbon, hafnium, zirconium, boron

Tramp elements: silver, boron, silicon

12

Cast Nickel Based Alloy Compositions

Alloy Ni Cr Co Mo W Ta Cb Al Ti Fe Mn Hf C B Zr Others

Ni-Base Alloys

Alloy 713C 74 12.5 0.0 4.2 0.0 0.0 2.0 6.1 0.8 0.0 0.0 0.0 0.12 0.012 0.10

B-1900 64 8.0 10.0 6.0 0.0 4.0 0.0 6.0 1.0 0.0 0.0 0.0 0.10 0.015 0.10

C-1023 58 15.5 10.0 8.5 0.0 0.0 0.0 4.2 3.6 0.0 0.0 0.0 0.16 0.006 0.00

CMSX- 2 66 8.0 4.6 0.6 7.9 5.8 0.0 5.6 0.9 0.0 0.0 0.0 0.00 0.000 0.00

GTD-111 60 14.0 9.5 1.5 3.8 2.8 0.0 3.0 4.9 0.0 0.0 0.0 0.10 0.01 0.03

GTD-222 51 22.5 19.0 0.0 2.0 1.0 0.8 1.2 2.3 0..0 0.0 0.0 0.10 0.010 0.01

IN-100 60 10.0 15.0 3.0 0.0 0.0 0.0 5.5 4.7 0.0 0.0 0.0 0.18 0.014 0.06 1.0 V

IN-738LC 61 16.0 8.5 1.7 2.6 1.7 0.9 3.4 3.4 0.0 0.0 0.0 0.11 0.010 0.05

IN-939 48 22.5 19.9 0.0 2.0 1.4 1.0 1.9 3.7 0.0 0.0 0.0 0.15 0.009 0.09

IN-792 61 12.4 9.0 1.9 3.8 3.9 0.0 3.1 4.5 0.0 0.0 0.0 0.12 0.020 0.10

MarM-002 61 9.0 10.0 0.0 10 2.5 0.0 5.5 1.5 0.0 0.0 1.5 0.14 0.015 0.05

MarM-247 60 8.3 10.0 0.7 10 3.0 0.0 5.5 1.0 0.0 0.0 1.5 0.10 0.015 0.05

PWA-1483 61 12.8 9.0 1.9 3.8 4.0 0.0 3.6 4.0 0.0 0.0 0.0 0.07 0.0 0.0

Rene-N5 62 7.0 8.0 2.0 5.0 7.0 0.0 6.2 0.0 0.0 0.0 0.2 0.0 0.0 0.0 3.0 Re

13

PRECIPITATION STRENGTHENING

Superalloys are strengthened by carbide and gamma-prime () precipitates Substitution of aluminium for nickel in lattice results in phase of the

composition Ni3Al. Titanium and niobium can substitute for aluminium in The volume fraction of phase formed is a function of the hardener content

Increasingcreep

strength

Increasing volume

phase in Ni-based superalloy

14

Gamma Prime () Strengthening (cont.)

Cuboidal primary phase

Spherical secondary phase

15

PRECIPITATION STRENGTHENING

For a given volume of in nickel superalloy, maximum strength is developed at anoptimum precipitate size

Heat treatments are used to create the optimum precipitate size(s).

In reality, it is both the size and spacing between precipitates that is responsible for strength.

16

ALLOY HEAT TREATMENT

17

GRAIN BOUNDARY HARDENING: BY CARBIDES

MC carbides form at high temperature and precipitate throughout the matrix with little influence on strength

M23C6 or M6C particles form preferentially along grain boundaries during aging cycles and service exposure

The particles inhibit grain boundary sliding and add to strength however there is an optimum carbon addition level (0.1-0.2%) beyond which properties degrade

Grain boundary carbide particles in IN939 alloy

18

GRAIN SIZE STRENGTHENING

Fine grain sizes provide high tensile and fatigue strengths, BUT lower creep strengths result

Fatigue of IN718, IN901 and Waspaloy

Creep of IN738

19

GRAIN ORIENTATION ADVANCED CASTING TECHNOLOGIES

Equiaxed

Directionally Single Cry

stal (SC)(polycrystalline] Solidified (DS) [monocrystalline]

20

GRAIN ORIENTATION

Grain boundaries are the weakest-link in polycrystalline superalloy behaviour. If the stresses are highly uniaxial, and the service temperature is very high, significant improvements can be made through controlling grain-boundary orientation or eliminating them altogether during casting.

equiaxed columnar single crystalPolycrystal DS Directional SX

Solidification

21

TRENDS IN TURBINE BLADE ALLOYS and GRAIN ORIENTATION

22

COMPARATIVE DS, SX AND POLYCRYSTAL PROPERTIES

23

SURFACE STABILITY: OXIDATION AND HOT CORROSION Engineering alloys are not stainless, they all form oxide

scales in air. Scale formation rate is a function of temperature and

environment Some native scales are not protective (Fe, Mg) Some native scales are protective (Al, Cr, Ti) Alloying enough protective element into non-

protective can impart protection (ie: 12+% chromium into iron makes stainless steel)

Protective elements can be added to base alloy or clad over as a coating

24

NATIVE OXIDE SCALES HIERARCHY FOR SUPERALLOYS AND COATINGS

Al2O3 Very Protective NiAl2O4 NiTa2O6

CrTaO4 Cr2O3 Protective

NiCr2 O4 CoCr2O4 NiTiO3

NiO Not helpfulCoOTiO2W, Mo, refractory oxides

25

Advanced Design Turbine Blades (Industrial Frame Engines Now Using Aero Cooling, Aero Alloys)

Manufacturer/Model First Stage Turbine Blade / Bucket

Alstom-GT24/26Single Crystal, Ni-BaseMatrix CooledVPS-NiCoCrAlY with APS-TBC

GE-Frame 7FADirectionally Solidified, GTD111Serpentine Cooling w/TurbulatorsLPPS-CoCrAlY/DVC-TBC, Plus Internal Coatings

Siemens V84.3ASingle Crystal PWA1480VPS-CoNiCrAlYSi

Plus Internal Coatings

Siemens- Westinghouse 501G

Directionally Solidified CM247Serpentine, Film & Showerhead VPS-NiCoCrAlY/TBC

GE LM2500+RR RB211 GT

Single Crystal N5 (GE), CMX4 (RR)Serpentine, Film & Showerhead PT Al Coating plus internal Coating (LM2500+)

Slide Number 1Slide Number 2SuperalloysTypical Gas Turbine Component MaterialsSUPERALLOYSSUPERALLOY DEFINITIONALLOY PROPERTIESMECHANICAL PROPERTIESCompositions and Properties - Nickel Based AlloysSUPERALLOY PROPERTIESSUPERALLOY DESIGNCast Nickel Based Alloy CompositionsPRECIPITATION STRENGTHENINGGamma Prime () Strengthening (cont.)PRECIPITATION STRENGTHENINGALLOY HEAT TREATMENTGRAIN BOUNDARY HARDENING:BY CARBIDESGRAIN SIZE STRENGTHENINGGRAIN ORIENTATION ADVANCED CASTING TECHNOLOGIESGRAIN ORIENTATIONSlide Number 21COMPARATIVE DS, SX AND POLYCRYSTAL PROPERTIESSURFACE STABILITY:OXIDATION AND HOT CORROSIONNATIVE OXIDE SCALES HIERARCHY FOR SUPERALLOYS AND COATINGSAdvanced Design Turbine Blades(Industrial Frame Engines Now Using Aero Cooling, Aero Alloys)