Applications of Thermo-Calc and DICTRAweb.access.rwth-aachen.de/THERMOCALC/proceedings/...Siemens...

Copyright © Siemens AG 2009. All rights reserved.

Applications of Thermo-Calc and DICTRA

Thermo-Calc Users MeetingAachen, 2010-09-09

Sebastian PiegertE F PR GT EN M&T MPD3

Page 2 2010-09-09 Sebastian PiegertCopyright © Siemens AG 2009. All rights reserved.

Siemens Energy Sector F PR GT EN M&T MPD3

Outline

Introduction

Siemens Gas Turbines


Base Material CharacterisationBraze Alloy Development and Heat Treatment OptimisationHeat Treatment for a Welding Process

Summary



Introduction Structure of Siemens

Source: Siemens

Industry

Healthcare

Energy



Introduction Structure of Siemens Energy

Power Distribution

Power Transmission

Oil & Gas Fossil Power

Generation

Renewable

Energy

Energy Service

Products and Solutions for Energy −

in 6 Divisions



Introduction Overall Vision of Siemens Energy Sector



Siemens Gas Turbines Portfolio

SGT-100

SGT-200

SGT-300

SGT-400

SGT-500

SGT-600

SGT-700

SGT-800

SGT6-2000E

SGT5-2000E

SGT6-4000F

SGT6-5000F

SGT5-4000F

Industrial Gas TurbinesLarge Gas Turbines Values in MW @ ISO Conditions

292

200

187

168

113

47

30

25

17

13

8

7

5

375SGT5-8000H

SGT-400

SGT5-8000H



Siemens Gas Turbines SGT5-4000F (V94.3A) Gas Turbine

Compressor, 15 stage with CDA airfoils in all stages and with side-wall correction. One variable guide vane row. Developed with P&W.

Annular combustion chamber with 24 hybrid burners. Hot gas path with air cooled metallic or ceramic heat shield

4 -stage turbineBlade 1 and 2 single crystalline and directionally solidifiedFilm-cooling of blades and vanes of stage 1 and 2

Rotor with Hirth serration and single tie bolt. Quick thermal response because of rotor internal flow passages.

Excellent thermal balance due to:- Quick and stiff rotor- Conical turbine flow path

Due to thermal balance:- Quick start up- Hot restart capability

Combustion Chamber

Compressor

24 Hybrid Burners

Turbine



Siemens Gas Turbines Air Cooled Turbine Blades and Vanes

Bla

de

1 o

f SG

T5-4

00

0F

γ’

precipitation hardened Ni-based Superalloy

500

1000

1500

1940 1950 1960 1970 1980 1990 2000

Melting Interval1300

750

T Material= 85% Tm

Turbine Inlet Temperature

Co-BaseCarbide Hardening

Ni-Baseγ/γ‘

Ni-Base -

SXγ/γ‘

JahrTe

mp

erat

ur

°C




Coating-SubstrateInteraction

Estimation ofnon Conformances

Heat Treatment Optimisation

Base MaterialCharacterisation

Braze AlloyDevelopment

Base AlloyDevelopment Thermo-Calc Version S

with TTNi

7 Database

DICTRA 25 with MobNi1 Database

http://www.thermocalc.com/DICTRA.htm



700

800

900

1000

1100

1200

1300

1400

0 1 2 3 4 5 6 7 8

T /

°C

minmaxTCC

Base Material Characterisation

–

IN 738 LC

Possible Calculations:solvus temperaturesamount of phases with respect to temperaturephase compositionsprediction of occurrence of detrimental phases such as s, h etc.

Applications:estimation of “allowed” service temperaturesdefinition of heat treatmentsinfluence of material non-conformances in regard to composition can be evaluated

Liq

Sol γ‘

M23

C6

MC

M3B

2 σ

Lite

ratu

revs

. Cal

cula

ted

T so

lvFr

acti

on

of

ph

ases

vsT

1: γ

2: MC

3: γ’

4: M23C6

5: M3B2

6: L

Tsol Tbraze



Development of a Boron Free Braze

Scope:Develop a boron free braze alloy to avoid formation of brittle phases.

Approach:use Ge as MPD

high solubility in Niforms a to γ’ isomorphous phase (β-Ni3Ge)

Problem:limited availability of phase diagramsGe not in database (TTNi7)

Bin

ary

Ni-

Ge

Phas

e D

iag

ram

Tbraze



Development of a Boron Free Braze Braze

Alloy Development

Issue:Ge braze BfBX-5 with X wt.-% MPD low melting eutectics, condensed γ’and TCP phases remain in jointpoor mechanical properties at 850 °C

Action:new alloy based on René 80Y wt.-% Ge are adequate for a liquidus lower than 1200 °Cdetrimental blocky phases and condensed γ’ were found within jointrefinement by means of TCC

Conclusion and Result:reduction of refractory metals Mo/Wreduction of γ’ formersmicrostructure is now homogeneousM

od

ifie

dB

raze

Allo

yR

ené

80

+ X

Y w

t.-%

Ge(

Si)

1: γ

2: Laves

3: L

4: γ’

5: NiAl

1: γ

2: Laves

3: L

4: γ’

5: NiAl

↓Al -

→Ti -

↓↓Mo -

↓W



Development of a Boron Free Braze Heat Treatment Development

Issue:appropriate braze cycle not available

Model:problem with moving interfacestart of calculation with L (braze) and γ (René 80)expected phases attached to lower interface, i.e. joint centre, as inactivew0 = 200 µm

Result:isothermal single phase solidification of old braze (BfBX-5) within 22 hsignificant reduction of tiso with René80 based brazeformation of Laves if Thold is significantly lowered

Req

uir

edTi

me

for

Solid

ific

atio

nTw

oC

ellM

od

el

1204 °C/24 h

1204 °C/30 min +1140 °C/24 h

15 h

7 h

René

80/BfBX-5 –

40/60

René

80 + Y Ge

Formationof Laves



high temperature strength – γ’Ni3(Al,Ti)corrosion and oxidation resistant

BUT very prone to crackingin HAZ during welding (hot cracking)

solidification crackingcracking due to remeltinghot cracking due to loss in ductility

strain age crackingGenerally:

high γ’-content = higly prone to cracking

3 Gew.-% ≤ cAl + ½ cTiTa, Nb, Hf form also γ’

Weldability

of Superalloys

readly

weldable

Mo

le F

ract

ion

of γ‘

in t

ypic

al S

up

eral

loys



Increase

of Weldability

Low Low heatheat

inputinputBeamBeam

weldingwelding

(Laser, EB)(Laser, EB)

MicroMicro--PlasmaPlasma--PowderPowder--WeldingWelding

OptimisationOptimisation

of of weldingwelding

parametersparameters

HeatHeat

treatmenttreatment

WeldWeld--fillersfillersDuctileDuctile

weldweld--fillersfillers

(IN 625, IN 617, (IN 625, IN 617, HastelloyHastelloy

X)X)

PrePre--heatheat

treatmenttreatment

((solutioningsolutioning, ,

overageingoverageing) )

SubsequentSubsequent

heatheat

treatmenttreatment

HotboxHotbox--WeldingWelding



DICTRA Heat Treatment for Micro Cladding

Fact:

γ‘

precipitation causes shrinkage and hence induces tensile stresses which can lead to cracking of weld deposition.

Question:

What heating rate is favourable to avoid strain age cracking?

Solution:

Result:low heating rate shall be appliedhigh heating rates led to a shift of precipitation to higher temperatures resulting in altered growth ratetotal volume fraction precipitated deviates by only 10 %

-5E-23

0

5E-23

1E-22

1.5E-22

2E-22

2.5E-22

3E-22

700 800 900 1000

T / °C

V /

m3 /s

20 K/min

10 K/min

5 K/min

γ’

γ

rγ’(T,t)

641 nm

movinginterface

Prec

ipit

atio

n R

ate

vs. T

Mo

del

Geo

met

ry

minK20

minK5

min≤≤T

V&

&

.



Summary

Major Advantages:speed up of investigations and decrease time to marketreduction of experimental testing“long term trials” within hours/daysdefinition of process windows even of unknown systems possiblecalculation of stable and metastable„real“ systemsversatile: any type of calculation which is related to thermodynamics and/or kinetics can be thought ofinfluence of distinct parameters on the system can be studied separately

Disadvantages:non-validated material systems might give inappropriate resultssome knowledge about the systems is requiredmechanical properties cannot be predicted



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.

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