Manufacturing of advanced Rotor Forgings for Highly Efficient Fossil Power Plants

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1 Manufacturing of advanced Rotor Forgings for Highly Efficient Fossil Power Plants B. Donth N. Blaes D. Bokelmann Saarschmiede GmbH Freiformschmiede Völklingen, Germany 1

2 Content Introduction Development of the creep resistant steel grades FB2 and FB4 9-12% Cr Steels for Steam Temperatures 620 C Boron-free and boron-containing steel grades Manufacturing of turbine rotor forgings in steel grade FB2 Pilot turbine rotor Commercial turbine rotor parts Manufacturing of trial rotor forging in steel grade FB4 Manufacturing Testing Summary and Conclusions 2

Efficiency of Coal Fired Power Plants Coal maintains to be a major source for future power generation CO 2 emissions must be reduced for the protection of the climate Combination of increasing use of

3 Efficiency of Coal Fired Power Plants Coal maintains to be a major source for future power generation CO 2 emissions must be reduced for the protection of the climate Combination of increasing use of coal world wide and protection of the climate technology development to increase efficiency high efficiency coal fired power plants new advanced and reliable high temperature steels are needed World energy demand expands by 45% until 2030 (1,6% per year) Coal accounting for more than a third of the overall rise IEA, World Energy Outlook 2008 Reference case 3

4 Efficiency of Coal Fired Power Plants - High efficiency Power Plants require high steam temperature and high pressure Rotor shaft for HP and IP parts with suitable creep properties at operating temperature - Strong development of creep resistant steels 4

5 Content Introduction Development of the creep resistant steel grades FB2 and FB4 9-12% Cr Steels for Steam Temperatures 620 C Boron-free and boron-containing steel grades Manufacturing of turbine rotor forgings in steel grade FB2 Pilot turbine rotor Commercial turbine rotor parts Manufacturing of trial rotor forging in steel grade FB4 Manufacturing Testing Summary and Conclusions 5

Rotor materials for USC Power Plants Boron-alloyed 10% Cr-steels Abe, Kern and Viswanathan (Eds.). Creep-resistant steels, 2008 Creep rupture strength at 100.

6 Rotor materials for USC Power Plants Boron-alloyed 10% Cr-steels Abe, Kern and Viswanathan (Eds.). Creep-resistant steels, 2008 Creep rupture strength at h for new martensitic Cr-Steels Addition of boron enables to increase application temperature by ca. 20 C 100,000 hrs rupture strength about 100 MPa Resistance to corrosion Resistance to thermo-mechanical cycling Sufficient weldability 6

7 Rotor materials for USC Power Plants Chemical composition of new Steels for high temperature rotor application 7

8 High Temperature Materials for Turbine Shafts Materials used for high temperature rotors 30 CrMoNiV 5-11 HP/IP up to 565 C 23 CrMoNiWV 8-8 HP/IP/LP up to 565 C European X12 CrMoWVNbN HP/IP up to 610 C European COST E X14 CrMoVNbN 10-1 HP/IP up to 600 C European COST F TMK1 HP/IP up to 600 C Japanese similar Cost F X13CrMoCoVNbNB HP/IP up to 625 C European COST FB2 X18 CrMoVNbB 10 1 HP/IP up to 625 C European COST FB4 Application development of COST E material for high temperature rotors (Saarschmiede) Year Now launch of COST FB2 into regular production 8

9 Content Introduction Development of the creep resistant steel grades FB2 and FB4 9-12% Cr Steels for Steam Temperatures 620 C Boron-free and boron-containing steel grades Manufacturing of turbine rotor forgings in steel grade FB2 Pilot turbine rotor Commercial turbine rotor parts Manufacturing of trial rotor forging in steel grade FB4 Manufacturing Testing Summary and Conclusions 9

0,14 0,10 0,40 0,010 0,005 9,50 1,60 0,20 0,22 0,010 0,012 0,10 0,030 0,0100 1,40 0,065 0,005 ESU 1300, 56600kg 930726 0,135 0,076

10 COST FB2 Trial Shaft Ingot Making Chemical analysis steel grade C Si Mn P S Cr Mo Ni V Al As Cu N B Co Nb Ti X 12CrMoCoB 9 FB2 min. 0,12 0,05 0,30 9,00 1,40 0,10 0,18 0,005 0,015 0,0080 1,20 0,045 SSF max. 0,14 0,10 0,40 0,010 0,005 9,50 1,60 0,20 0,22 0,010 0,012 0,10 0,030 0,0100 1,40 0,065 0,005 ESU 1300, 56600kg ,135 0,076 0,31 0,0058 0,001 9,28 1,51 0,15 0,19 0,007 0,002 0,031 0,026 0,0091 1,33 0,053 0,001 Developing of boron content in ESR ingot ESR-Ingot for manufacturing of the FB2 trial shaft 10

11 COST FB2 Trial rotor - Forging ESR ingot: Ø 1300 mm / 57 t Forging: Ø 1260 mm / 30 t Forging Temperature: 1170 C 11

COST FB2 Trial Rotor Red of Area [%] 100 90 80 FT 7 270 ppm B FB2 100ppm B 70 60 50 40 30 20 10 Final shape of the rotor 0 600 650 700 750 800

12 COST FB2 Trial Rotor Red of Area [%] FT ppm B FB2 100ppm B Final shape of the rotor Temperature [ C] Forgeability of boron-alloyed Cr-steels Limitation of boron content to max. 100ppm 12

13 FB2 Trial rotor - Heat Treatment PHT (preliminary heat treatment after forging) - martensitic transformation QHT (quality heat treatment) - austenitizing 1100 C/water spray - 1 st tempering 570 C, - 2 nd tempering 700 C 13

14 COST FB2 Trial rotor UT inspection FB2 trial rotor in machined condition after QHT 14

15 COST FB2 Trial rotor mechanical properties B T D E F 1050 ca. 300 ca. 200 D2 815 C 410 A A B C D1 D2 E F 0.2 YS [MPa] RT 625 C UTS [MPa] RT 625 C EL [%] RT 15,0 15,0 16,0 15,0 15,0 12,5 10,0 625 C 25,3 26,7 26,0 28,7 22,5 23,0 RA [%] RT 625 C 55,1 84,7 56,4 83,8 56,4 82,1 55,1 82,5 53,8 45,3 70,5 32,5 67,4 Impact [J] RT 35, 27, , 36, , 42, , 28, , 18, , 23, , 21, 27, FATT [ C]

16 COST FB2 Trial rotor microstructure good through-hardenability for 1200mm - 100% tempered martensite - no d ferrite detectable - grain size (ASTM):

17 COST FB2 Trial rotor creep properties COST FB2 Creep rupture properties of trial rotors (Kern et al, 9 th Liege Conference, 2010) 17

18 COST FB2 regular production parts COST FB2 (X13CrMoCoVNbNB 9 2 1) Production Parts (since 2007) 7 IP-turbine rotor parts ( 5 ESR Ingots, Ø 1300mm, 30mt 56mt) Part- No.: component Melt No. dimensions for QHT [mm] weigth for QHT [kg] delivery weigth [kg] 1 IP turbine rotor part x IP turbine rotor part x IP turbine rotor part x IP turbine rotor part x IP turbine rotor part x IP turbine rotor part x IP turbine rotor part x

19 COST FB2 regular production parts Mechanical Properties and MDDS 19

20 Content Introduction Development of the creep resistant steel grades FB2 and FB4 9-12% Cr Steels for Steam Temperatures 620 C Boron-free and boron-containing steel grades Manufacturing of turbine rotor forgings in steel grade FB2 Pilot turbine rotor Commercial turbine rotor parts Manufacturing of trial rotor forging in steel grade FB4 Manufacturing Testing Summary and Conclusions 20

21 COST FB4 Trial rotor h Creep Strength [MPa] Comparison COST FB2 FB4 (X18 CrMoVNbB 10 1) - comparable creep properties, also significantly better creep strength than boron free steels (COST E/F) - similar chemical composition, but FB4 without cobalt more cost-effective COST FB 4 (X18 CrMoVNbB 10 1) Chemical composition Type C Mn Cr Ni Mo V B N 2 Nb W Co FB2 0,13 0,35 9,3 0,10 1,50 0,20 0,0100 0,020 0,05 1,3 FB4 0,18 0,80 9,3 0,15 1,50 0,27 0,0100 0,015 0, Alloy Design Criterion 1%CrMoV X18CrMoVNbB9 1 Alloy 617 X12CrMo(W)VNbN %Cr MoV Temperature [ C] K.H. Mayer: Werkstoffentwicklungen für Effizienzsteigerung von fossilen Kraftwerken, Düsseldorf,

COST FB4 Trial rotor FB4 material very promising for high temperature turbine rotor application Problem: difficulties in manufacturing, because of insufficient UT- Detectability (Minimum Detectable

22 COST FB4 Trial rotor FB4 material very promising for high temperature turbine rotor application Problem: difficulties in manufacturing, because of insufficient UT- Detectability (Minimum Detectable Defect Size - MDDS) Several attempts without success A new heat treatment have been applied to trial shaft of COST 536 program solution: perlitic phase transformation for grain refinement 100 : 1 Pikrin-HCl-verdünnt µm 30% Perlite 22

COST FB4 Trial rotor Chemical analysis steel grade C Si Mn P S Cr Mo Ni V Al As Cu Sn Sb N B Co W Nb X 18CrMoVNbB 10-1 1.4926.04 min.

23 COST FB4 Trial rotor Chemical analysis steel grade C Si Mn P S Cr Mo Ni V Al As Cu Sn Sb N B Co W Nb X 18CrMoVNbB min. 0,17 0,05 0,20 9,00 1,40 0,10 0,24 0,005 0,010 0,0080 0,055 SSF FB4 max. 0,19 0,10 0,40 0,010 0,005 9,60 1,60 0,20 0,29 0,010 0,012 0,10 0,0040 0,0010 0,020 0,0100 0,075 ESR 1300 mm Melt No ,18 0,09 0,28 0,005 0,001 9,21 1,50 0,17 0,03 0,007 0,003 0,03 0,0035 0,0006 0,016 0,0097 0,012 0,003 0,066 ESR Ingot: 1300mm, 45t weight X 9CrMoCoB FB2 min. 0,12 0,30 9,00 1,45 0,10 0,18 0,015 0,0080 1,20 SSF max. 0,14 0,08 0,40 0,010 0,005 9,50 1,55 0,20 0,22 0,008 0,006 0,035 0,0040 0,001 0,030 0,0090 1,40 0,040 0,005 0,060 COST FB 4 trial rotor - real production size forging (29,8 t) - sectioning of the rotor after PHT 23

COST FB 4 Trial Rotor Heat Treatment Preliminary Heat Treatment -

- 2 MHz) reading point 1 2 3 4 5 after PHT MDDS 2,0 6,3 5,3 5,3 2,7 after

Final QHT MDDS (KSR) at core [mm QHT* MDDS 12:00 2,1 5,7 04:00 1,9 6,0

24 COST FB 4 Trial Rotor Heat Treatment Preliminary Heat Treatment - martensitic transformation perlitic transformation MDDS (KSR) at core [mm - 2 MHz) reading point after PHT MDDS 2,0 6,3 5,3 5,3 2,7 after QHT* MDDS 12:00 2,1 5,7 04:00 1,9 6,0 08:00 2,1 5,3 sectioning First QHT Final QHT MDDS (KSR) at core [mm - 2 MHz) reading point after PHT MDDS 2,0 6,3 5,3 5,3 2,7 after QHT* MDDS 12:00 2,1 5,7 04:00 1,9 6,0 08:00 2,1 5,3 24

COST FB4 Trial rotor UT results after grain refining and second quality heat treatment MDDS [mm] reading point diameter 2 MHz 4 MHz 5 MHz 12:00 04:00 08:00 12:00 04:00 08:00 12:00 04:00 08:00 1.

25 COST FB4 Trial rotor UT results after grain refining and second quality heat treatment MDDS [mm] reading point diameter 2 MHz 4 MHz 5 MHz 12:00 04:00 08:00 12:00 04:00 08:00 12:00 04:00 08: ,1 1,1 1,1 0,7 0,9 0,8 0,9 0,8 0, ,1 1,1 1,1 0,8 0,8 0,8 0,8 0,8 0, ,0 1,0 1,0 0,8 0,7 0,7 0,7 0,7 0, ,1 1,1 1,1 0,8 0,8 0,8 1,0 0,9 1, ,8 1,5 1,5 MDDS significantly better than for FB2 MDDS values in the range of boron-free steels (COST E) can be achieved 25

26 COST FB4 Trial rotor - mechanical properties T [ C] T1 A1 A2 0.2 YS [MPa] UTS [MPa] EL [%] 20 16,1 16,9 16, ,9 27,1 RA [%] 20 56,4 61,2 58, ,9 92 Impact [J] 20 25, 29, , 48, , 22, FATT [ C] microstructure 100% martensite 100% martensite 100% martensite 26

27 COST FB4 Trial rotor - microstructure A1 core T1 surface ASTM 3-6 ASTM 00 to : 1 RNO - Ätzmittel 200 µm 27

28 Content Introduction Development of the creep resistant steel grades FB2 and FB4 9-12% Cr Steels for Steam Temperatures 620 C Boron-free and boron-containing steel grades Manufacturing of turbine rotor forgings in steel grade FB2 Pilot turbine rotor Commercial turbine rotor parts Manufacturing of trial rotor forging in steel grade FB4 Manufacturing Testing Summary and Conclusions 28

29 Summary and Conclusions Long standing experience with 10 % Cr steel type Cost E with an reliable production route - market share is increasing Steel type Cost FB 2 is a successful development for steam temperatures 620 C Successful manufacturing and testing of FB2 Trial rotor Introduction of FB2 into commercial application - several production parts have been already manufactured Type Cost FB 4 alloy is a promising candidate alloy and alternative to FB 2 Successful manufacturing and testing of FB4 Trial rotor Perlitic Transformation improved MDDS considerably due to grain refinement 29

30 Many thanks for your attention! The Saarschmiede GmbH Freiformschmiede is a company of the Saarstahl Group. Work on COST FB4 sponsored by: Bundesministerium für Wirtschaft und Technologie on the basis of a decision of the German Parliament 30

Martensitic steels for rotors in ultra-supercritical power plants

Martensitic steels for rotors in ultra-supercritical power plants 6 G. Zeiler Bohler Edelstahl GmbH & Co KG, Kapfenberg, Austria 6.1 Introduction Energy is a basic necessity for a high standard of living