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Research Article
 

Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment



Muhd Faiz Mat, Yupiter H.P. Manurung, Norasiah Muhammad, Siti Nur Syahirah Ahmad, Marcel Graf and Mohd Shahar Sulaiman
 
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ABSTRACT

Background and Objective: The properties of SS316L stainless steel plate are significant due the wide range of usage of the stated material. It can be governed by the chemical composition and microstructure. This study deals with the investigation of major parameters used for predicting the grain size of austenitic stainless steel SS316L at different temperature range. The major grain growth variables such as; kinetic exponent and grain growth rate constant had been studied to interpret the mechanism in the samples with different heat treatment settings. Materials and Methods: The material investigated was austenitic stainless steel SS316 L. Samples were isothermally held at various temperatures and holding time. Results: Based on the results, the kinetic rates were plotted by using the Arrhenius equation to predict the grain size. Using this method the estimated grain size shows an acceptable error percentage up to 12.5% for temperature at 1100°C and for the temperature of 1200°C or above. Conclusion: it is concluded the grain growth will be abnormal at higher temperature range, the precipitate that occurs at the grain boundary layer can be implemented for a modified Arrhenius equation.

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Muhd Faiz Mat, Yupiter H.P. Manurung, Norasiah Muhammad, Siti Nur Syahirah Ahmad, Marcel Graf and Mohd Shahar Sulaiman, 2020. Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment. Journal of Applied Sciences, 20: 91-96.

DOI: 10.3923/jas.2020.91.96

URL: https://scialert.net/abstract/?doi=jas.2020.91.96
 
Received: December 30, 2019; Accepted: February 08, 2020; Published: February 15, 2020


Copyright: © 2020. This is an open access article distributed under the terms of the creative commons attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.

INTRODUCTION

The properties of SS316L stainless steel plate are important due the wide range of usage of the stated material. The presence of precipitation such as; carbides and nitrides at grain boundaries is considered for commercial importance1,2. As such, the importance of microstructure has a large effect towards the mechanical properties and for this reason, it is important to control the grain size. For instance, the yield strength, hardness, fatigue strength, tensile strength and impact strength are increased with decreasing of grain size3. On the other hand, one of the most important factors controlling austenite grain structure at the end of cold-working and annealing operations is the austenite stability with respect to strain induced transformation4. Consequently, to improve the strength of a material is to make the grains as small as possible by increasing the amount of grain boundary. Small grain sizes are accompanied by high volume of grain boundaries and as a result, the more grain boundaries that be present, the higher the strength becomes.

Previous research has indicated the grain growth behavior at elevated temperature has been investigated and an attempt to model the recrystallization and grain growth of steels by using various models such as; the Potts (Monte Carlo) model and Arrhenius model5,6. As to austenitic stainless steels, several studies have been reported on the mechanical properties and grain growth behaviour7,8. However, less information can be gathered about the grain size before and after the heat treatment process that includes transformation process, especially at the range of in between 1173 K and 1273 K (900 and 1000°C) when the recrystallization process and long-term temperature exposures happens. As one of the important parameters to be controlled when specific mechanical properties is required for steel is the austenitic mean grain size.

The objective of this research was to predict the austenitic mean grain size by using the grain growth formula based on locally sourced material and verify its variable value for future use. Furthermore, the variable concluded from this research will be used for numerical computation algorithm of grain growth formula.

MATERIALS AND METHODS

Experimental site: The research was carried out at Chair of Welding Department of Engineering, Technische Universitat Chemnitz from June-July, 2019.

Materials and research tools: The material used for this experimental work was a SS316L stainless steel plate supplied by Irfan Bina Enterprise. The steel was supplied as hot-rolled plate with a thickness of 4 mm. The chemical composition of the plate was analyzed by Arc Spectrometer (Q4 Qantas). Sample were heat treated by using a DIL 805A/D quenching and deformations dilatometers. Microstructural observation was conducted with Leica optical microscope integrated with Leica Material Workstation software. Microstructural images were captured by an optical microscope Olympus BX60.

Research procedure: All research procedure was following the guidelines provided by American Society for Testing and Materials (ASTM) related to grain size standards.

Data collection: The actual austenite grain sizes were determined according to ASTM E112 by Leica Material Workstation by using the single circle method while the estimated austenite grain size was obtained from statistical analysis of Arrhenius equation5,6.

Experimental design: In order to predict the grain size of the tested austenite stainless steel at elevated temperature, SS316L stainless steel plate with a thickness of 4 mm were isothermally held at temperature of 1173 and 1273 K (900 and 1000°C) for various time (30, 60, 120 and 240 sec). The data obtained from the experiment can be used to predict the mean grain size at different temperature.

Parameters measured: From the classical theory of normal grain growth, the grain growth kinetics after primary recrystallization can be described in the following form9:

Image for - Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment
(1)

where, D is the mean grain size obtained by holding time t, is a grain growth rate constant and n is the grain growth kinetic exponent. The apparent activation energy Q for grain growth can be described by an Arrhenius equation:

Image for - Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment
(2)

where, k0 is a constant, T is the temperature and R is the universal gas constant.

RESULTS

Material verification: The chemical composition result obtained from the QMatrix Analysis Machine in weight percent are according to the ASTM standard A240 for 316L stainless steel as shown in Table 1.

Table 1:QMatrix analysis results for SS316L stainless steel plate (weight percent)
Image for - Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment

Table 2:Average grain size
Image for - Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment

Table 3:Values of K, n and fitted K* and n* for the tested SS316L stainless steel plate
Image for - Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment
*K: Estimated grain growth rate constant value, *n: Estimated kinetic exponent value

Image for - Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment
Fig. 1:Logarithmic plots of the grain size vs. the holding time after annealing at the annealing temperatures of 1173 K and 1273 K

Image for - Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment
Fig. 2:Growth rate constant as a function of the reciprocal of the process temperature

Image for - Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment
Fig. 3:Actual grain size vs. estimated grain size for different holding time

Austenitic stainless steel grain size: The austenite grain size after experiment for each sample was collected and shown in Table 2. An estimated value of K and n represented in Table 3 was obtained by using the Arrhenius equation to estimate the austenite grain size at temperature of 1100 and 1200°C.

The grain growth kinetic exponent was obtained from the slope of the straight line in log-log plots of the grain size vs time by using linear regression fit as shown in Fig. 1 as the graph plotted can be used to predict both of the values for other temperature range. The plot of the grain growth rate constant vs. the reciprocal of the temperature shows a linear relationship, as shown in Fig. 2 as higher the temperature the higher the grain growth constant value will be. Figure 3 presents the actual grain size vs. the estimated grain size value calculated by using the Arrhenius equation.

Figure 4 and 5 present the typical micrographs of austenite grain boundaries under different heating temperatures and holding times. It was observed austenite grain size can be calculated and grow gradually when annealing time increases from 30-240 sec. The result shows that austenitic stainless steel SS316L at the temperature of 1200°C or above will indicate an abnormal grain growth.

Grain size prediction: An estimated grain growth rate constant value of K* and estimated kinetic exponent value of n* have been obtained from the statistical analysis.

Image for - Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment
Fig. 4(a-d): Micrograph of austenite grain boundaries under different heat treatment conditions (a) 1173 K, 30 sec, (b) 1173 K, 60 sec, (c) 1173 K, 120 sec and (d) 1173 K, 240 sec

Image for - Variable Analysis for Grain Size Prediction of Austenitic Stainless Steel SS316l Using Heat Treatment
Fig. 5(a-d): Micrograph of austenite grain boundaries under different heat treatment conditions (a) 1273 K, 30 sec, (b) 1273 K, 60 sec, (c) 1273 K, 120 sec and (d) 1273 K, 240 sec

An estimated grain size at different temperature range can be calculated by using the Arrhenius equation. The percentage of error between actual and estimated grain size is shown in Fig. 3. It shows that the error percentage is increasing for each holding time above the temperatures of 1473 K (1200°C). It shows the grain growth of austenitic stainless steel SS316L was growing abnormally and can’t be predicted by using the Arrhenius equation. This clearly indicates the presence of other particles at the grain boundary layer that slows down the grain growth kinetics.

DISCUSSION

The value of the predicted grain size at the temperature range of 900-1100°C was proven that it can be approximately calculated by using the Arrhenius equation10-12. At temperature above 1200°C the predicted grain size error percentage were higher and considered at an unacceptable range. This unique condition for austenitic stainless steel has been reported in previous studies and has been proven again to be the same condition for SS316L grade stainless steel13-15. Thus, a modification should be made to consider the existence of material precipitation in austenitic stainless steel SS316L at higher temperature range.

Previous studies on the grain size of bulk 316L stainless steel related to temperature evolution at high temperature range are mostly related to welding process16. As temperature rises, the grain growth rate increases, but at a certain temperature the grain growth behave abnormally considering the presence of other particles that respond only at higher temperature range17,18. The presence of other particles that prevent the grain boundaries from moving are the most common factors, thus the Arrhenius equation should be modified for austenitic stainless steel material category. According to previous studies, these main particles can mainly be very small sulfides, nitrides, carbides or silicate particles exist in the grain boundary of stainless steel material4,17-19. Future experiment will be planned at different temperature range to carry out the verification of the grain size of austenitic stainless steel SS316L at higher temperature while considering precipitation investigation at microstructural level. Thus, the grain size prediction can be expanded to higher temperature range to understand its grain growth behavior during high temperature evolution.

CONCLUSION

This study advances the idea that grain size can be predicted by using Arrhenius equation for austenitic stainless steel by investigating the material behavior at elevated temperature. Although, the grain growth will be abnormal at higher temperature range, the precipitate that occurs at the grain boundary layer can be implemented for a modified Arrhenius equation.

SIGNIFICANCE STATEMENT

This study discover the grain growth mechanism of SS316L is grain boundary migration as grain boundary can be completely consumed by surrounding grains while having irregular shape that can be beneficial for grain growth behaviour of austenitic stainless steel. This study will help the researcher to uncover the critical areas of austenitic stainless steel grain growth behaviour at elevated temperature that many researchers were not able to explore. Thus, a new theory on grain growth behaviour at elevated temperature for austenitic stainless steel may be arrived at.

ACKNOWLEDGMENTS

The authors would like to express their gratitude to staff member of Smart Manufacturing Research Institute (SMRI) and Research Interest Group: Advanced Manufacturing Technology (RIG:AMT) at Faculty of Mechanical Engineering, Universiti Teknologi MARA (UiTM) as well as Professorship of Virtual Production Engineering at Chemnitz University of Technology (CUT) in Germany for encouraging this research. The experiment was carried out at Technische Universitat Chemnitz in Germany. This research is financially supported by Geran Inisiatif Penyeliaan (GIP) from Phase 1/2016 with Project Code: 600-IRMI 5/3/GIP (073/2019).

REFERENCES
1:  Triwiyanto, A., P. Hussain, A. Rahman and M.C. Ismail, 2013. The influence of nitriding time of AISI 316L stainless steel on microstructure and tribological properties. Asian J. Scient. Res., 6: 323-330.
CrossRef  |  Direct Link  |  

2:  Lippold, J.C., S.D. Kiser and J.N. DuPont, 2009. Welding Metallurgy and Weldability of Nickel-Base Alloys. 1st Edn., John Wiley & Sons, New York, USA., ISBN: 978-0-470-08714-5, Pages: 456.

3:  Gladman, T. and D. Dulieu, 1974. Grain-size control in steels. Met. Sci., 8: 167-176.
CrossRef  |  Direct Link  |  

4:  Spruiell, J.E., J.A. Scott, C.S. Ary and R.L. Hardin, 1973. Microstructural stability of thermal-mechanically pretreated type 316 austenitic stainless steel. Metall. Trans., 4: 1533-1544.
CrossRef  |  Direct Link  |  

5:  Chen, X., X. Chen, H. Xu and B. Madigan, 2015. Monte Carlo simulation and experimental measurements of grain growth in the heat affected zone of 304 stainless steel during multipass welding. Int. J. Adv. Manuf. Technol., 80: 1197-1211.
CrossRef  |  Direct Link  |  

6:  Lee, S.J. and Y.K. Lee, 2008. Prediction of austenite grain growth during austenitization of low alloy steels. Mater. Des., 29: 1840-1844.
CrossRef  |  Direct Link  |  

7:  Haden, C.V., G. Zeng, F.M. Carter III, C. Ruhl, B.A. Krick and D.G. Harlow, 2017. Wire and arc additive manufactured steel: Tensile and wear properties. Addit. Manuf., 16: 115-123.
CrossRef  |  Direct Link  |  

8:  Yilmaz, O. and A.A. Ugla, 2017. Microstructure characterization of SS308LSi components manufactured by GTAW-based additive manufacturing: Shaped metal deposition using pulsed current arc. Int. J. Adv. Manuf. Technol., 89: 13-25.
CrossRef  |  Direct Link  |  

9:  Burke, J.E. and D. Turnbull, 1952. Recrystallization and grain growth. Progr. Met. Phys., 3: 220-292.
CrossRef  |  Direct Link  |  

10:  Moon, J., J. Lee and C. Lee, 2007. Prediction for the austenite grain size in the presence of growing particles in the weld HAZ of Ti-microalloyed steel. Mater. Sci. Eng.: A, 459: 40-46.
CrossRef  |  Direct Link  |  

11:  Choi, J. and J. Mazumder, 2002. Numerical and experimental analysis for solidification and residual stress in the GMAW process for AISI 304 stainless steel. J. Mater. Sci., 37: 2143-2158.
CrossRef  |  Direct Link  |  

12:  Aval, H.J., S. Serajzadeh and A.H. Kokabi, 2009. Prediction of grain growth behavior in HAZ during gas tungsten arc welding of 304 stainless steel. J. Mater. Eng. Perform., 18: 1193-1200.
CrossRef  |  Direct Link  |  

13:  Kishore, H. and R.K. Saxena, 2017. Experimental and numerical method to predict the micro-hardness of SS316. Int. J. Eng. Technol. Sci. Res., 4: 211-224.
Direct Link  |  

14:  Chavan, A., Y. Gaikhe, S. Huddedar and R. Pawade, 2012. 3D surface characterization of electrophoretic deposition assisted polishing of SS316L. J. Applied Sci., 12: 929-937.
CrossRef  |  Direct Link  |  

15:  Zietala, M., T. Durejko, M. Polanski, I. Kunce and T. Plocinski et al., 2016. The microstructure, mechanical properties and corrosion resistance of 316 L stainless steel fabricated using laser engineered net shaping. Mater. Sci. Eng.: A, 677: 1-10.
CrossRef  |  Direct Link  |  

16:  Xu, X., G. Mi, Y. Luo, P. Jiang, X. Shao and C. Wang, 2017. Morphologies, microstructures and mechanical properties of samples produced using laser metal deposition with 316 L stainless steel wire. Opt. Lasers Eng., 94: 1-11.
CrossRef  |  Direct Link  |  

17:  Tian, Y., N. Chekir, X. Wang, A. Nommeots-Nomm, R. Gauvin and M. Brochu, 2018. Effect of heat treatments on microstructure evolution and grain morphology of alloy 625 with 0.4 wt% boron modification fabricated by laser wire deposition. J. Alloys Compd., 764: 815-823.
CrossRef  |  Direct Link  |  

18:  Russell, K.C., 2003. Precipitate coarsening and grain growth in steels. Proceedings of the Symposium on the Thermodynamics, Kinetics, Characterization and Modeling of Austenite Formation and Decomposition, November 9-12, 2003, Chicago, IL., USA., pp: 437-456.

19:  Geng, S., J. Sun, L. Guo and H. Wang, 2015. Evolution of microstructure and corrosion behavior in 2205 duplex stainless steel GTA-welding joint. J. Manuf. Process., 19: 32-37.
CrossRef  |  Direct Link  |  

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