Laser Metal Deposition for Maintenance, Repair and
Overhaul at Siemens Fossil Power Generation
AKL - International Laser Technology Congress
Dr. D. Thomaidis, Dr. M. Ott, N. Arjakine,
Dr. G. Bostanjoglo
Aachen Mai 9th, 2012
© Siemens AG 2012.
Content
 Content
 Introduction
 Examples of advanced repair welding technology at Siemens AG
 Laser cladding
 Laser build-up welding
 Summary
© Siemens AG 2012
Page 2
Siemens Energy Sector E F PR GT TBV
Siemens Energy Sector – New set-up for the future requirements of the market
Sector
Energy
Industry
Oil & Gas
Division
Fossil Power Gen.
Wind Power
Solar & Hydro
Energy Service
Power Transmission
Healthcare
Infrastructure
& Cities
Business Unit
Products (E F PR)
Steam Turbines (E F PR SU)
Generators (E F PR GN)
Business
Gas Turbines (E F PR GT)
Segment
System Integration (E F PR SI)
Sales (E F PR S)
Feeder Plants (E F PR FP)
© Siemens AG 2012
Page 3
Siemens Energy Sector E F PR GT TBV
Siemens Energy Sector – New set-up for the future requirements of the market
Energy products and solutions – in 6 Divisions
Products and solutions – in 6 Divisions
Fossil Power
Generation
(E F)
Wind
Power
(E W)
Solar &
Hydro
(E X)
Oil & Gas
(E O)
Energy
Service
(E S)
Power
Transmission
(E T)
© Siemens AG 2012
Page 4
Siemens Energy Sector E F PR GT TBV
Siemens large-scale gas turbines
375 MW
SGT5-8000H
50 Hz
292 MW
SGT5-4000F
SGT5-2000E
168 MW
274 MW
SGT6-8000H
60 Hz
208 MW
SGT6-5000F
SGT6-2000E
113 MW
© Siemens AG 2012
Page 5
Siemens Energy Sector E F PR GT TBV
Products Business Unit – Innovation highlight: Siemens SGT-8000H series gas
turbine
Market requirements
High load flexibility
through improved
blade cooling system
 Strong fluctuations in grid demand and feed-in
require higher operational flexibility
 The focus on “clean energy” is driving the demand
for more efficient power generation solutions
 The high-tech class is the fastest growing gas
turbine market segment of the future
Improved
combustion
system for
Ultra-low NOx
Siemens SGT-8000H series solution
Four-stage
turbine
Evolutionary
3D compressor
blades
Proven rotor design,
free radial thermal
expansion and
central tie bolt
 Reduction of emissions per kWh generated
 Higher efficiency: over 60% in combined cycle
operation
 Maximum operational flexibility due to highest partload efficiency and highest ramp rates
Customer benefits




Lower investment costs per kW
Lower lifecycle costs
High reliability and availability
Short start-up times and high operational flexibility
© Siemens AG 2012
Slide
Page 66
Siemens Energy Sector E F PR GT TBV
Development tendency of materials for increased turbine inlet temperature in gas
turbines
Turbine Inlet Temperature
T°C
1800
1500
1250
1100
950
800
1950
1965
1980
1995
2010
2025
© Siemens AG 2012
Page 7
Siemens Energy Sector E F PR GT TBV
Prager’s plot of weldability versus Al and Ti content - Cracking Categories
6
Types of cracking which may occur during and after welding
include:
a
b
Aluminium, %
• Solidification cracking (SC)
• Liquation cracking (LC)
• Ductility dip cracking (DDC)
• Reheat (strain age) cracking (RHC)
IN 100
5
Difficult To Weld
4
Udimet 600
IN738
Rene 80
3
Udimet 500
IN 939
2
1
Readily Weldable
IN 625
Rene 41
Inconel 718
1
For example: a) - SC and b) - LC
Astroloy
2
3
Titanium, %
4
5
6
Source: Journal
of Materials Engineering and
Performance
Volume 6(5)
October 1997
© Siemens AG 2012
Page 8
Siemens Energy Sector E F PR GT TBV
Solutions to minimize cracking caused by the welding process
Lower heat input during
welding
Beam Welding
Micro Plasma Powder Welding
Improvement of welding parameters
Pre weld H/T
Heat treatment
(solutioning / overaging)
Post weld H/T
Hotbox – welding
Welding filler materials
Use of ductile welding filler materials
© Siemens AG 2012
Page 9
Siemens Energy Sector E F PR GT TBV
Solutions to minimize cracking caused by the welding process
 Development of a LMD process at room temperature for highly γ’-strengthened nickel-base superalloys with
a γ’-strengthened filler material to create material properties for a structural repair.
 Development of process parameters for LMD with reduced heat affected zone in the base material to avoid
negative impact on the substrate microstructure.
 Development of a numerical model and resulting process parameters for LMD to adjust the cooling rates
during solidification
© Siemens AG 2012
Page 10
Siemens Energy Sector E F PR GT TBV
Hard facing technology – Demand and Solution
Transitions wear at the MC
 Gap of only 3,5-4mm at the transitions
 Casing deformation during operation
 Hammering and abrasion occurs

Laser hard facing of the transitions
 Increasing the wear resistance
 Repairable by TIG welding on site
 Field testing ongoing
Hard facing of
the cooling air ring
© Siemens AG 2012
Page 11
Siemens Energy Sector E F PR GT TBV
Status: Hard facing Solution
• Hard facing by laser welding for production
• Field test shows good results
• Application for Siemens patent
• Replacement of Parts possible
during scheduled Major Outages
Hard faced spots
Product improvement available
For New Part and Service!
Testing in GT
Production Laser weld
20mm
© Siemens AG 2012
Page 12
Siemens Energy Sector E F PR GT TBV
m-TIG vs. Laser Powder Welding
Manual TIG-welding
 few layers
 remarkable amount of overlaying
material
 respective re-contouring effort
 high process time
Blade tip restoration by
Laser powder welding
 multiple layers
 small amount of overlaying
material
 reduced re-contouring effort
 low process time
© Siemens AG 2012
Page 13
Siemens Energy Sector E F PR GT TBV
m-TIG vs. Laser Powder Welding
Improved Quality
Manual TIG-welding
Laser powder welding
 HAZ:
up to 0.5 mm
visible 3 mm
 respective high
heat input
 risk of crack
introduction &
propagation
 HAZ: up to 0.15 mm
 reduced heat input
Laser process is more robust, faster and
offers better quality
© Siemens AG 2012
Page 14
Siemens Energy Sector E F PR GT TBV
Further Laser Powder Applications
Repair of…
…rubbing marks at stationary blades…
Combination of Laser and
Hot-Box
Possibility of high-strength matching filler
welding
…and at guide ring
© Siemens AG 2012
Page 15
Siemens Energy Sector E F PR GT TBV
Summary
 The low weldability of advanced GT materials represents a significant challenge.
 The combination of advanced welding technologies like LMD with in-depth materials knowledge and their
behavior during welding allow the repair of these material systems.
 The ability to perform such repair of GT components reduces life cycle costs and repair lead time, lowers
the scrap rate and makes repair and refurbishment more cost effective for gas turbine owners.
© Siemens AG 2012
Page 16
Siemens Energy Sector E F PR GT TBV
Thank you for your attention – any questions?
© Siemens AG 2012
Page 17
Siemens Energy Sector E F PR GT TBV
Disclaimer
This document contains forward-looking statements and information – that is, statements related to future, not past, events. These statements may be identified either orally or in writing
by words as “expects”, “anticipates”, “intends”, “plans”, “believes”, “seeks”, “estimates”, “will” or words of similar meaning. Such statements are based on our current expectations and
certain assumptions, and are, therefore, subject to certain risks and uncertainties. A variety of factors, many of which are beyond Siemens’ control, affect its operations, performance,
business strategy and results and could cause the actual results, performance or achievements of Siemens worldwide to be materially different from any future results, performance or
achievements that may be expressed or implied by such forward-looking statements. For us, particular uncertainties arise, among others, from changes in general economic and business
conditions, changes in currency exchange rates and interest rates, introduction of competing products or technologies by other companies, lack of acceptance of new products or services by
customers targeted by Siemens worldwide, changes in business strategy and various other factors. More detailed information about certain of these factors is contained in Siemens’ filings
with the SEC, which are available on the Siemens website, www.siemens.com and on the SEC’s website, www.sec.gov. Should one or more of these risks or uncertainties materialize, or
should underlying assumptions prove incorrect, actual results may vary materially from those described in the relevant forward-looking statement as anticipated, believed, estimated,
expected, intended, planned or projected. Siemens does not intend or assume any obligation to update or revise these forward-looking statements in light of developments which differ
from those anticipated.
Trademarks mentioned in this document are the property of Siemens AG, it's affiliates or their respective owners.
© Siemens AG 2012
Page 18
Siemens Energy Sector E F PR GT TBV