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Mechanical properties optimization of the modified 410 martensitic stainless steel by heat treatment process
Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 5 (2018) 14918–14922
www.materialstoday.com/proceedings
ICAPMA_2017
Mechanical properties optimization of the modified 410 martensitic stainless steel by heat treatment process Efendi Mabruri*, Siska Prifiharni, Moch. Syaiful Anwar, Toni B. Romijarso, Bintang Adjiantoro Research Center for Metallurgy and Materials, Indonesian Institute of Sciences (LIPI), Kawasan Puspiptek Gd. 470 Serpong, Tangerang Selatan 15314, Indonesia
Abstract The 410-3Ni3Mo martensitic stainless steels for steam turbine blade application have been developed with improved pitting resistance compared to standard 410 steels. This paper reports the optimization of mechanical properties and microstructure of the developed steels by heat treatment process. The experimental results showed that the steels quenched at 1100oC had highest values of both tensile strength and elongation after subsequent high temperature tempering of 600, 650 and 700oC. Whereas, the mechanical properties of the steels decreased as tempering temperature increased. The best combination of tensile strength of 1300 MPa and elongation of 10.5% were obtained by quenching at 1100oC and subsequent tempered at 600oC. The mechanical properties obtained in this study were correlated with the microstructure developed in the steels after heat treatment characterized by XRD and SEM. © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of 3rd International Conference on Applied Physics and Materials Applications. Keywords: Modified 410-3Ni3Mo; Martensitic stainless steel ; Heat treatment ; Mechanical properties optimization ; Steam turbine blade
1. Introduction In steam power plant, turbine blade is one of the criticl parts subjected to severe condition of stress and environment. The failures of the turbine blades are frequently encountered during services especially in the last stage of low pressure blades. The most typical failure mechanism are environmentally assisted craking [1,2] due to
* Corresponding author. Tel.: +62-756-0911; fax: +62-756-0553. E-mail address: [email protected] 2214-7853© 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of 3rd International Conference on Applied Physics and Materials Applications.
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14919
interaction of high stress and corrosive environment operated in the turbine system. In order to improve the resistance to the failure, the turbine blade material which usually made from martensitic stainless steels type 403/410 has been continuously modified with improved mechanical and corrosion properties [3,4,5]. Recently, the 410-3Ni3Mo martensitic stainless steels have been developed with improved pitting resistance and better mechanical properties compared to standard 410 steels [6,7]. The addition of Mo is suggested to increase both pitting resistance and strength, while Ni improves toughness and avoiding -ferrite due to high amount of Mo. Thus, the combination of Ni and Mo in quite high similar concentration is suggested to optimize the microstructure resulting in good combination of mechanical and corosion properties. It is well-known that the microstructure and mechanical properties of the martensitic stainless steels is strongly depend on the heat treatment process. The heat treatment of the martensitic stainless steels consists of austenitizing and quenching to facilitate formation of hard martensite structure and subsequent tempering to improve ductility and toughness. The austenitizing is performed at high temperature of austenite phase and determines the extent of carbide dissolution, dissolved alloying elements, grain growth and martensite characteristic. While, tempering is conducted at a lower temperature to facilitate relaxation of hard martensite and precipitation of carbides. However, the tempering process for steam turbine blade application should be performed at temperature higher than steam temperature in order to ensure stable microstructure during services. The proper combination of austenitizing or quenching temperature and tempering temperature results in suitable microstructure and optimized properties of the martensitic stainless steels. This paper repotrs the optimization of mechanical properties and microstructure of the developed 410-3Ni3Mo steel by combination of quenching temperature and tempering temperature. 2. Experimental details The 410-3Ni3Mo martensitic stainless steel ingots with 5x5x10 cm in sizes were prepared in induction melting furnace. The chemical composition of the steel is shown in Table 1 according to testing using Optical Emission Spectrometer (OES). To make wrought alloy, the ingots were forged at high temperature of 1200oC several time until the sizes down to 2 cm of thickness. The forged steels were annealed at temperature 800oC for 20 h for softening to facilitate machining the samples for testing. The annealed steels were then machined to prepared specimens for tensile test, XRD and SEM. The steel samples were austenitized at various temperatures of 100, 1050 and 1100 oC for 1 h followed by quenching in oil. The austenitized samples were subsequently tempered at various temperature of 600, 650 and 700 oC for 1 h followed by air cooling. The heat treated samples for tensile test were surface ground to remove oxidation scales. The tensile testing of the steels specimen was carried out by using universal testing machine until the specimen broke. The samples for microstructural observation were prepared by standard metallographic operations and etching was performed by using Kalling reagent. The microstructural images were taken by Scanning Electron Microscope (SEM). The samples for XRD were surface ground with SiC abrasive paper until grit size of P800. Table 1. Chemical composition (wt. %) of the 410-3Ni3Mo steels prepared in this work. Steel
C
S
P
Mn
Si
Cr
Mo
Ni
Fe
410-3Ni3Mo
0.10
0.005
0.02
0.61
0.24
12.73
2.52
2.93
Bal.
3. Results and discussion The stress-strain curves of tensile test for the 410-3Ni3Mo martensitic stainless steels in various heat treatment conditions were presented in Fig. 1. It can be seen that the steel quenched at 1000oC and tempered at any applied temperature (Fig. 1.a) exhibits no plastic region and no strain hardening region as well. The narrow plastic region can be observed from the curves for the steels quenched at higher temperature in Fig. 1 (a) and (b). The largest region for plstic region and strain hardening exhibited by the steels quenched at 1100oC and tempered at 600oC. The absence or narrow of the plastic region in these steels are assosiated with the existence of martensite phase in the
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microstructure of tempered steels. The martensite is ferrite phase with lattice distortion or extention due to supersaturation with carbon, therefore it absorbs little or no deformation energy during tensile test. The larger plastic region in the steels quenched at higer temperature (1050 and 1100 oC) may be related to the existence of reatined austenite phase (in addition to martensite) in the microstructure, the softer phase which can absorb deformation energy. As it already known that higher austenitizing temperature before quenching dissolves more carbides and increases amount of austenite phase and may provide retained austenite after quenching to room temperature [8]. The largest plastic region combined with largest maximum stress and strain exhibited by the steel quenched at 1100oC and tempered at 600oC. As the consequence, this steel has highest toughness with widest area below the stress-strain curve as displayed in Fig. 1(c).
(a)
(b)
(c)
Fig. 1. Stress-strain curves of the 410-3Ni3Mo steel in tempered condition at 600, 650 and 700 oC with previously quenched at (a) 1000 (b) 1050 and (c) 1100 oC.
(a)
(b)
Fig. 2. (a) Tensile strength and (b) elongation of the 410-3Ni3Mo steel at various quenching and tempering temperatures.
The tensile strength and elongation of the 410-3Ni3Mo steel as function of tempering temperature for various quenching temperature are shown in Fig. 2. It can be observed from this figure that both the tensile strength and elongation tend to decrease with increasing of tempering temperature from 600 to 700oC for all quenching temperatures applied in this work. With respect to quenching temperature, the strength and elongation have similar trend, where they slightly decrease from 1000 to 1050oC and then increase at 1100oC. The steels quenched at 1100oC show largest value of both tensile strength and elongation for all applied tempering temperatures. The combination of largest tensile strength of 1300 MPa and largest elongation of 10.5% was obtained by quenching at
E. Mabruri et al./ Materials Today: Proceedings 5 (2018) 14918–14922
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1100oC and subsequent tempering at 600oC. This good combination of high strength and toughness is suitable for structural parts experienced with high stress in service such as steam turbine blade. The mechanical properties of the steels are strongly related to the phases contained in its microstructures. The microstructures of the 410-3Ni3Mo characterized by XRD and SEM are presented in Fig. 3 and Fig. 4, respectively. To observe the change of microstructure with heat treatment parameters, the combination of quenching and tempering temperatures of 1000-600, 1100-600 and 1100-700oC was selected. The indentified phases in the steel heat treated at 1000-600oC are -Fe and small amount of -Fe. At the higher quenching temperature 1100oC with constant tempering temperature 600oC (1100-600) the peaks of -Fe phase significantly diminishes and peaks of Fe phase increase. The -Fe phase appears again in the steel with higher tempering temperature 700oC as in XRD peaks of 1100-700.
Fig. 3. XRD peaks of of the 410-3Ni3Mo steel at several combination of quenching and tempering temperatures.
Fig. 4. SEM images for the microstructure of the 410-3Ni3Mo steel with heat treatment condition of (a) 1000-600 (b) 1100-600 and (c) 1100-700oC.
The -Fe phase in the steel can be estimated as martensite and -ferrite which can be seen in the SEM image in Fig. 4(a) with lath and island-like shapes, respectively. The formation of -ferrite in this steel is attributed to Mo which is a ferrite stabilizing element with relatively high level of 3 wt.%. Other researcher also reported the formation of -ferrite in the martensitic stainless steel containing 1 wt.% Mo and even in steel with relatively zero Mo [9]. The -ferrite exists as high temperature phase in equilibrium diagram and its formation at room temperature occurs due to non-equilibrium solidification. The high temperature annealing should be accomplished to diminish this phase. The austenitizing at 1000oC applied in this work has not been removed this phase. Higher austenitizing temperature of 1100oC reduces the -ferrite phase as can be seen in XRD peaks in Fig. 3 (1100-600) and SEM image in Fig. 4(b). The appearing -Fe in the steel at higher tempering temperature 700oC associated with decomposition of -Fe into ferrite and carbides. In other hand, the -Fe phase appearing in XRD with strong peaks for the steel quenched at 1100oC (as in XRD peaks 1100-600 and 1100-700 in Fig. 3) is estimated as retained
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austenite. The existence of retained austenite in the higher austenitizing temperature indicating incomplete transformation of austenite to martensite in room temperature. This is attributed to depression of martensite start temperature (Ms) due to increasing of dissolution of carbide forming elements such as Cr and Mo at higher temperature into austenite phase [8]. At lower quenching temperature 1000oC the retained austenite almost does not appear (XRD peaks 1000-600) indicating very low extent of dissolution of carbide forming elements into austenite at this temperature. With respect to martensite as the major contributor for hardening of these steels, the influence of heat treatment combination can be observed to change the fraction and size of the martensite. At lower quenching temperature 1000oC the fraction, the fraction of martensite seem to be lower due to the existence of large amount of -ferrite (Fig.4). At higher quenching temperature 1100oC the fraction of martensite increase with diminishing of -ferrite. At this quenching temperature, the subsequent tempering at 600oC results in martensite with relatively fine size. While, coarse martensite is observed in the steel tempered at higher tempering temperature 700oC as in Fig. 4(c). As the conclusion, with increasing quenching temperature to 1100oC, the -ferrite significantly diminishes and the retained austenite content increases. Whereas, with increasing tempering temperature to 700oC, some retained austenite decomposes to ferrite and carbides and the martensite coarsening occurs. The steel quenched at 1100oC and tempered at 600oC which consist of fine-size martensite, retained austenite and less amount of -ferrite exhibits the best combination of strength and elongation. 4. Conclusion The mechanical properties and microstructure of the 410-3Ni3Mo martensitic stainless steel has been investigated in relation with various combination of quenching and tempering temperatures. The tensile strength and elongation tend to decrease with increasing of tempering temperature from 600 to 700oC for all quenching temperatures applied in this work. The steels quenched at 1100oC show largest value of both tensile strength and elongation for all applied tempering temperatures. The combination of largest tensile strength of 1300 MPa and largest elongation of 10.5% was obtained by quenching at 1100oC and subsequent tempering at 600oC with the microstructure consisted of fine-size martensite, retained austenite and less amount of -ferrite. Acknowledgements The authors would like to thank Indonesian Institute of Sciences (LIPI) for supporting this research through The LIPI Excelence Program. References [1] G. Das, S.G. Chowdhury, A.K. Ray, S.K. Das, D.K. Bhattacharya, Turbine blade failure in a thermal power plant. Eng. Fail. Anal. 10 (1) (2003) 85-91. [2] M. Schönbauer, S. E. Stanzl-Tschegg, A. Perlega, R. N. Salzman, N. F. Rieger, S. Zhou, A.Turnbull, D.Gandy, Fatigue life estimation of pitted 12% Cr steam turbine blade steel in different environments and at different stress ratios, Int. J. Fatigue. 65 (2014) 33-43. [3] I. Calliari , M. Zanesco, M. Dabala, K. Brunelli, E. Ramous, Investigation of microstructure and properties of a Ni-Mo martensitic stainless steel, Mater. Des. 29 (2008) 246-250. [4] E.Mabruri, Z.A.Syahlan, Sahlan, M.S.Anwar, T.B. Romijarso, B.Adjiantoro, Effect of tempering temperature on hardness and impact resistance of the 4101Mo martensitic stainless steels for steam turbine blades, Int. J. Eng.Technol. 8 (6) (2017) 2547-2551. [5] E.Mabruri, Z.A.Syahlan, Sahlan, M.S.Anwar, S.A. Chandra, T.B. Romijarso, B.Adjiantoro, Influence of austenitizing heat treatment on the properties of the tempered type 410-1Mo stainless steel, IOP Conf. Series: Mat. Sci. Eng. 202 (2017) (012085)1-7. [6] E.Mabruri, M.S.Anwar, S.Prifiharni, T.B. Romijarso, B.Adjiantoro, Tensile properties of the modified 13Cr martensitic stainless steels, AIP Conf. Proc. 1725 (2016) (020039)1-5. [7] Moch. Syaiful Anwar, Toni Bambang Romijarso, Efendi Mabruri, The Pitting Resistance of The Modified 13Cr Martensitic Stainless Steel in Chloride Solution, Int. J. Electrochem. Sci., 12 (2017) xx – yy. [8] L.D. Barlow, M. Du Toit, Effect of the austenitising heat treatment on the microstructure and hardness of martensitic stainless steel AISI 420, J. Mat. Eng. Perform. 21(7) (2012) pp. 1327-1336. [9] V.Thursdiyanto, E.J.Bae,E.R.Baek, E.R., Effect of Ni Contents on the Microstructure and Mechanical Properties of Martensitic Stainless Steel Guide Roll by Centrifugal Casting, J. Mater. Sci. Technol., 24 (3) (2008) 343-346.
ScienceDirect Materials Today: Proceedings 5 (2018) 14918–14922
www.materialstoday.com/proceedings
ICAPMA_2017
Mechanical properties optimization of the modified 410 martensitic stainless steel by heat treatment process Efendi Mabruri*, Siska Prifiharni, Moch. Syaiful Anwar, Toni B. Romijarso, Bintang Adjiantoro Research Center for Metallurgy and Materials, Indonesian Institute of Sciences (LIPI), Kawasan Puspiptek Gd. 470 Serpong, Tangerang Selatan 15314, Indonesia
Abstract The 410-3Ni3Mo martensitic stainless steels for steam turbine blade application have been developed with improved pitting resistance compared to standard 410 steels. This paper reports the optimization of mechanical properties and microstructure of the developed steels by heat treatment process. The experimental results showed that the steels quenched at 1100oC had highest values of both tensile strength and elongation after subsequent high temperature tempering of 600, 650 and 700oC. Whereas, the mechanical properties of the steels decreased as tempering temperature increased. The best combination of tensile strength of 1300 MPa and elongation of 10.5% were obtained by quenching at 1100oC and subsequent tempered at 600oC. The mechanical properties obtained in this study were correlated with the microstructure developed in the steels after heat treatment characterized by XRD and SEM. © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of 3rd International Conference on Applied Physics and Materials Applications. Keywords: Modified 410-3Ni3Mo; Martensitic stainless steel ; Heat treatment ; Mechanical properties optimization ; Steam turbine blade
1. Introduction In steam power plant, turbine blade is one of the criticl parts subjected to severe condition of stress and environment. The failures of the turbine blades are frequently encountered during services especially in the last stage of low pressure blades. The most typical failure mechanism are environmentally assisted craking [1,2] due to
* Corresponding author. Tel.: +62-756-0911; fax: +62-756-0553. E-mail address: [email protected] 2214-7853© 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of 3rd International Conference on Applied Physics and Materials Applications.
E. Mabruri et al./ Materials Today: Proceedings 5 (2018) 14918–14922
14919
interaction of high stress and corrosive environment operated in the turbine system. In order to improve the resistance to the failure, the turbine blade material which usually made from martensitic stainless steels type 403/410 has been continuously modified with improved mechanical and corrosion properties [3,4,5]. Recently, the 410-3Ni3Mo martensitic stainless steels have been developed with improved pitting resistance and better mechanical properties compared to standard 410 steels [6,7]. The addition of Mo is suggested to increase both pitting resistance and strength, while Ni improves toughness and avoiding -ferrite due to high amount of Mo. Thus, the combination of Ni and Mo in quite high similar concentration is suggested to optimize the microstructure resulting in good combination of mechanical and corosion properties. It is well-known that the microstructure and mechanical properties of the martensitic stainless steels is strongly depend on the heat treatment process. The heat treatment of the martensitic stainless steels consists of austenitizing and quenching to facilitate formation of hard martensite structure and subsequent tempering to improve ductility and toughness. The austenitizing is performed at high temperature of austenite phase and determines the extent of carbide dissolution, dissolved alloying elements, grain growth and martensite characteristic. While, tempering is conducted at a lower temperature to facilitate relaxation of hard martensite and precipitation of carbides. However, the tempering process for steam turbine blade application should be performed at temperature higher than steam temperature in order to ensure stable microstructure during services. The proper combination of austenitizing or quenching temperature and tempering temperature results in suitable microstructure and optimized properties of the martensitic stainless steels. This paper repotrs the optimization of mechanical properties and microstructure of the developed 410-3Ni3Mo steel by combination of quenching temperature and tempering temperature. 2. Experimental details The 410-3Ni3Mo martensitic stainless steel ingots with 5x5x10 cm in sizes were prepared in induction melting furnace. The chemical composition of the steel is shown in Table 1 according to testing using Optical Emission Spectrometer (OES). To make wrought alloy, the ingots were forged at high temperature of 1200oC several time until the sizes down to 2 cm of thickness. The forged steels were annealed at temperature 800oC for 20 h for softening to facilitate machining the samples for testing. The annealed steels were then machined to prepared specimens for tensile test, XRD and SEM. The steel samples were austenitized at various temperatures of 100, 1050 and 1100 oC for 1 h followed by quenching in oil. The austenitized samples were subsequently tempered at various temperature of 600, 650 and 700 oC for 1 h followed by air cooling. The heat treated samples for tensile test were surface ground to remove oxidation scales. The tensile testing of the steels specimen was carried out by using universal testing machine until the specimen broke. The samples for microstructural observation were prepared by standard metallographic operations and etching was performed by using Kalling reagent. The microstructural images were taken by Scanning Electron Microscope (SEM). The samples for XRD were surface ground with SiC abrasive paper until grit size of P800. Table 1. Chemical composition (wt. %) of the 410-3Ni3Mo steels prepared in this work. Steel
C
S
P
Mn
Si
Cr
Mo
Ni
Fe
410-3Ni3Mo
0.10
0.005
0.02
0.61
0.24
12.73
2.52
2.93
Bal.
3. Results and discussion The stress-strain curves of tensile test for the 410-3Ni3Mo martensitic stainless steels in various heat treatment conditions were presented in Fig. 1. It can be seen that the steel quenched at 1000oC and tempered at any applied temperature (Fig. 1.a) exhibits no plastic region and no strain hardening region as well. The narrow plastic region can be observed from the curves for the steels quenched at higher temperature in Fig. 1 (a) and (b). The largest region for plstic region and strain hardening exhibited by the steels quenched at 1100oC and tempered at 600oC. The absence or narrow of the plastic region in these steels are assosiated with the existence of martensite phase in the
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microstructure of tempered steels. The martensite is ferrite phase with lattice distortion or extention due to supersaturation with carbon, therefore it absorbs little or no deformation energy during tensile test. The larger plastic region in the steels quenched at higer temperature (1050 and 1100 oC) may be related to the existence of reatined austenite phase (in addition to martensite) in the microstructure, the softer phase which can absorb deformation energy. As it already known that higher austenitizing temperature before quenching dissolves more carbides and increases amount of austenite phase and may provide retained austenite after quenching to room temperature [8]. The largest plastic region combined with largest maximum stress and strain exhibited by the steel quenched at 1100oC and tempered at 600oC. As the consequence, this steel has highest toughness with widest area below the stress-strain curve as displayed in Fig. 1(c).
(a)
(b)
(c)
Fig. 1. Stress-strain curves of the 410-3Ni3Mo steel in tempered condition at 600, 650 and 700 oC with previously quenched at (a) 1000 (b) 1050 and (c) 1100 oC.
(a)
(b)
Fig. 2. (a) Tensile strength and (b) elongation of the 410-3Ni3Mo steel at various quenching and tempering temperatures.
The tensile strength and elongation of the 410-3Ni3Mo steel as function of tempering temperature for various quenching temperature are shown in Fig. 2. It can be observed from this figure that both the tensile strength and elongation tend to decrease with increasing of tempering temperature from 600 to 700oC for all quenching temperatures applied in this work. With respect to quenching temperature, the strength and elongation have similar trend, where they slightly decrease from 1000 to 1050oC and then increase at 1100oC. The steels quenched at 1100oC show largest value of both tensile strength and elongation for all applied tempering temperatures. The combination of largest tensile strength of 1300 MPa and largest elongation of 10.5% was obtained by quenching at
E. Mabruri et al./ Materials Today: Proceedings 5 (2018) 14918–14922
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1100oC and subsequent tempering at 600oC. This good combination of high strength and toughness is suitable for structural parts experienced with high stress in service such as steam turbine blade. The mechanical properties of the steels are strongly related to the phases contained in its microstructures. The microstructures of the 410-3Ni3Mo characterized by XRD and SEM are presented in Fig. 3 and Fig. 4, respectively. To observe the change of microstructure with heat treatment parameters, the combination of quenching and tempering temperatures of 1000-600, 1100-600 and 1100-700oC was selected. The indentified phases in the steel heat treated at 1000-600oC are -Fe and small amount of -Fe. At the higher quenching temperature 1100oC with constant tempering temperature 600oC (1100-600) the peaks of -Fe phase significantly diminishes and peaks of Fe phase increase. The -Fe phase appears again in the steel with higher tempering temperature 700oC as in XRD peaks of 1100-700.
Fig. 3. XRD peaks of of the 410-3Ni3Mo steel at several combination of quenching and tempering temperatures.
Fig. 4. SEM images for the microstructure of the 410-3Ni3Mo steel with heat treatment condition of (a) 1000-600 (b) 1100-600 and (c) 1100-700oC.
The -Fe phase in the steel can be estimated as martensite and -ferrite which can be seen in the SEM image in Fig. 4(a) with lath and island-like shapes, respectively. The formation of -ferrite in this steel is attributed to Mo which is a ferrite stabilizing element with relatively high level of 3 wt.%. Other researcher also reported the formation of -ferrite in the martensitic stainless steel containing 1 wt.% Mo and even in steel with relatively zero Mo [9]. The -ferrite exists as high temperature phase in equilibrium diagram and its formation at room temperature occurs due to non-equilibrium solidification. The high temperature annealing should be accomplished to diminish this phase. The austenitizing at 1000oC applied in this work has not been removed this phase. Higher austenitizing temperature of 1100oC reduces the -ferrite phase as can be seen in XRD peaks in Fig. 3 (1100-600) and SEM image in Fig. 4(b). The appearing -Fe in the steel at higher tempering temperature 700oC associated with decomposition of -Fe into ferrite and carbides. In other hand, the -Fe phase appearing in XRD with strong peaks for the steel quenched at 1100oC (as in XRD peaks 1100-600 and 1100-700 in Fig. 3) is estimated as retained
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austenite. The existence of retained austenite in the higher austenitizing temperature indicating incomplete transformation of austenite to martensite in room temperature. This is attributed to depression of martensite start temperature (Ms) due to increasing of dissolution of carbide forming elements such as Cr and Mo at higher temperature into austenite phase [8]. At lower quenching temperature 1000oC the retained austenite almost does not appear (XRD peaks 1000-600) indicating very low extent of dissolution of carbide forming elements into austenite at this temperature. With respect to martensite as the major contributor for hardening of these steels, the influence of heat treatment combination can be observed to change the fraction and size of the martensite. At lower quenching temperature 1000oC the fraction, the fraction of martensite seem to be lower due to the existence of large amount of -ferrite (Fig.4). At higher quenching temperature 1100oC the fraction of martensite increase with diminishing of -ferrite. At this quenching temperature, the subsequent tempering at 600oC results in martensite with relatively fine size. While, coarse martensite is observed in the steel tempered at higher tempering temperature 700oC as in Fig. 4(c). As the conclusion, with increasing quenching temperature to 1100oC, the -ferrite significantly diminishes and the retained austenite content increases. Whereas, with increasing tempering temperature to 700oC, some retained austenite decomposes to ferrite and carbides and the martensite coarsening occurs. The steel quenched at 1100oC and tempered at 600oC which consist of fine-size martensite, retained austenite and less amount of -ferrite exhibits the best combination of strength and elongation. 4. Conclusion The mechanical properties and microstructure of the 410-3Ni3Mo martensitic stainless steel has been investigated in relation with various combination of quenching and tempering temperatures. The tensile strength and elongation tend to decrease with increasing of tempering temperature from 600 to 700oC for all quenching temperatures applied in this work. The steels quenched at 1100oC show largest value of both tensile strength and elongation for all applied tempering temperatures. The combination of largest tensile strength of 1300 MPa and largest elongation of 10.5% was obtained by quenching at 1100oC and subsequent tempering at 600oC with the microstructure consisted of fine-size martensite, retained austenite and less amount of -ferrite. Acknowledgements The authors would like to thank Indonesian Institute of Sciences (LIPI) for supporting this research through The LIPI Excelence Program. References [1] G. Das, S.G. Chowdhury, A.K. Ray, S.K. Das, D.K. Bhattacharya, Turbine blade failure in a thermal power plant. Eng. Fail. Anal. 10 (1) (2003) 85-91. [2] M. Schönbauer, S. E. Stanzl-Tschegg, A. Perlega, R. N. Salzman, N. F. Rieger, S. Zhou, A.Turnbull, D.Gandy, Fatigue life estimation of pitted 12% Cr steam turbine blade steel in different environments and at different stress ratios, Int. J. Fatigue. 65 (2014) 33-43. [3] I. Calliari , M. Zanesco, M. Dabala, K. Brunelli, E. Ramous, Investigation of microstructure and properties of a Ni-Mo martensitic stainless steel, Mater. Des. 29 (2008) 246-250. [4] E.Mabruri, Z.A.Syahlan, Sahlan, M.S.Anwar, T.B. Romijarso, B.Adjiantoro, Effect of tempering temperature on hardness and impact resistance of the 4101Mo martensitic stainless steels for steam turbine blades, Int. J. Eng.Technol. 8 (6) (2017) 2547-2551. [5] E.Mabruri, Z.A.Syahlan, Sahlan, M.S.Anwar, S.A. Chandra, T.B. Romijarso, B.Adjiantoro, Influence of austenitizing heat treatment on the properties of the tempered type 410-1Mo stainless steel, IOP Conf. Series: Mat. Sci. Eng. 202 (2017) (012085)1-7. [6] E.Mabruri, M.S.Anwar, S.Prifiharni, T.B. Romijarso, B.Adjiantoro, Tensile properties of the modified 13Cr martensitic stainless steels, AIP Conf. Proc. 1725 (2016) (020039)1-5. [7] Moch. Syaiful Anwar, Toni Bambang Romijarso, Efendi Mabruri, The Pitting Resistance of The Modified 13Cr Martensitic Stainless Steel in Chloride Solution, Int. J. Electrochem. Sci., 12 (2017) xx – yy. [8] L.D. Barlow, M. Du Toit, Effect of the austenitising heat treatment on the microstructure and hardness of martensitic stainless steel AISI 420, J. Mat. Eng. Perform. 21(7) (2012) pp. 1327-1336. [9] V.Thursdiyanto, E.J.Bae,E.R.Baek, E.R., Effect of Ni Contents on the Microstructure and Mechanical Properties of Martensitic Stainless Steel Guide Roll by Centrifugal Casting, J. Mater. Sci. Technol., 24 (3) (2008) 343-346.