Frame 6B Users Group 2009 Cincinnati, OH Tuesday, June 9, 2009

PRACTICAL EXPERIENCE WITH THE DEVELOPMENT OF

SUPERALLOY REJUVENATION

Jonathan Joannides and Lloyd Cooke

Liburdi Turbine Services, Inc. 400 Highway 6 North

Dundas, Ontario, Canada, L9H 7K4

Introduction

• Rejuvenation was a process pioneered by Liburdi 25 years ago to:– Restore the component microstructure– Allow reuse of parts (rather than replacement)– Save the operator money

• This presentation will give an overview of how each of these goals is accomplished

Trends in turbine blade alloys

Introduction of Blade Alloys

History / Timeline

Alloys with Successful Rejuvenation Heat Treatments

ALLOY COMPONENTS ALLOY COMPONENTS

310 SS RT45 2nd stg NGV MarM002 RB211, Spey HP2

A286 Turbo-expander blades, Frame 3A, Frame 5A MarM247 W501F, 501K

C1023 Avon Vanes N155 RT45 1st stg NGV, RT56 vane

FSX414 Stage 1 Vanes Nimonic105 Avon, Spey

GTD111 Frame 3, 5, 6, 7, 9 Blades, PGT 5, 10, 16, 25 Nimonic115 Avon

GTD222 Stage 2 Vanes Nimonic263 Combustion hardware

Hastelloy X Combustion hardware Nimonic80A EAS-1 PT, AEI AP1 PT, Spey LP2

IN617 Combustion hardware Rene80 V84.3A1, LM1600, LM2500

IN700 DJ290R, W501AA, W101, W191 Udimet500 Industrial Frame Stage 3 Blades, RT45 stg 2, NP PGT10, NP PGT16 LPT blades

IN738

11N2, ELM116, LM1600, NP PGT LPT blades, Avon, Olympus HPT, Tornado CT2, EM610, V84.2, V94.2, W251, W501-D5A, W501F,

TB5000 CT2, TB5400 CT2

Udimet520 MHI 701D, W501-D5A, W101, W191

X45 Turbine Vanes

IN792 Avon, RB211 X750 W101, W191

IN939 DJ270G, Tornado CT1, V84.2, DC990, V series vanes Other Alloys 416 SS , C242 (Nimocast 242), C6Y Alloy,

M252, Nimonic108, Nimonic90, Rene77, S590

Gamma Prime Microstructure

IN738 – Medium DistributionNim105 – Lean Distribution

MarM002 – “As New” MarM002 – “Service-Aged”

Service-Induced Damage

• Rejuvenation repairs the highlighted forms of damage

– Microstructural aging

– Surface attack

– Tip wear– Creep– LCF

Why Rejuvenate ?

• F Class Repair Technologies Bucket “Full-Life” Repair and Rejuvenation– Plan A – Creep strength of buckets depletes each service interval –

replace parts at 48,000 or 72,000 hours– Plan B – Restore creep strength at the end of each service interval –

extend life of set for additional service intervals

Stress-Rupture Test Results

05

1015202530354045

NEW 24,000 48,000 72,000 96,000

Service Intervals

Plan A Plan B

New Part minimum test specification

Rejuvenation - Goal

• Goal of REJUVENATION is to bring the microstructure and mechanical properties back to a “like new” condition. This will allow a full life service interval just like a new part.

• Heat treatment is not just one simple heat treatment but usually a system of various heat treatments tailored to each alloy

• The Full Rejuvenation Processing• Solutioning step• Aging step(s)

• Hot Isostatic Pressing (HIP)

Rejuvenation

• Full vs. partial heat treatment – depends on if component is taken to full solution temp

• Liburdi Turbine Services utilizes Full Rejuvenation Heat Treatments

on all parts

• Partial heat treat used when coatings not removed• Partial used for aircraft blades not intended for high hours use

Rejuvenation

service run: before heat treatment

rejuvenation heat treatment

conventional heat treatment

as-manufactured condition

Service

Rejuvenation

Heat Treatment

Rejuvenation

• Success at restoring γ' morphology

• Success at restoring grain boundaries

IN 738

IN 738

Rejuvenation

• Role of HIPing– To close any creep voids

that may have formed– To relieve internal strains

caused by creep– Surfaces of the voids are

clean– Only effective for internal

porosity

Before HIP

After HIP

IN738

Rejuvenation – Results

• Rejuvenation reverses microstructural aging which restores the following: – LCF Properties– Tensile Properties– Creep Life

Experience – Frame 6

Real World Example

• Frame 7EA Buckets, rejuvenated 3 times, have reached twice the usual service life

• To 100,000 – 120,000 hours

Bucket at 92,000 hours. Ready for repair and further service.

2nd

Rejuv.3nd

Rejuv.

Real World Example

• Stage 1 Buckets – Workscope– Rejuvenation Heat Treatments– Strip/recoat

Case Study - 4 Unit - Frame 7EA Cogen Plant

• Net savings from extended service life– Stage 1 and Stage 2 Buckets– $8Million US – Avoided cost of new blades less cost of rejuvenation

Case Study - 4 Unit - Frame 7EA Cogen PlantO&M Savings Over Period 1996-2001

Real World Example

Summary

• Rejuvenation introduced by Liburdi in 1980 to the GT industry – IN738 Rejuvenation (1984), GTD111 Rejuvenation (1995)

• Each alloy has unique heat treatment process to fully restore original material properties. Processes must be uniquely qualified.

• Proven over hundreds of sets - full service intervals• Demonstrated 2 times and 3 times conventional service life

reliably achieved• Ultimately rejuvenation not only extends the life of buckets

(saving the operator money) it ensures that they are never more than 24,000 hours away from new part mechanical properties