Skip to main content
SpringerLink
Log in

Improvements in the Metallography of Ferritic–Martensitic Steels Through a Color Etching Procedure

  • Peer-reviewed Paper
  • Published:
Metallography, Microstructure, and Analysis Aims and scope Submit manuscript

Abstract

We introduce an improved etching procedure specially optimized for high-throughput metallography of ferritic–martensitic steels. The procedure involves color etching with or without interference contrast microscopy. By this process, prior austenite grain structure is unambiguously revealed, with accuracy equivalent to that yielded by EBSD. Additionally, the distinction between phases with similar crystallography is made possible through this process. The etchant also qualitatively indicates the presence of crystallographic texture in ferritic–martensitic steel.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10

Similar content being viewed by others

References

  1. V.F. Zackay, Thermomechanical processing. Mater. Sci. Eng. 25, 247–261 (1976)

    Article  CAS  Google Scholar 

  2. S. Sinha, D. Kim, E. Fleury, S. Suwas, Effect of grain boundary engineering on the microstructure and mechanical properties of copper containing austenitic stainless steel. Mater. Sci. Eng. A. 626, 175 (2015)

    Article  CAS  Google Scholar 

  3. B. Aashranth, M.A. Davinci, D. Samantaray, U. Borah, S.K. Albert, A new critical point on the stress-strain curve: delineation of dynamic recrystallization from grain growth. Mater. Des. 116, 495–503 (2017)

    Article  CAS  Google Scholar 

  4. B. Aashranth, M. ArvinthDavinci, D. Samantaray, U. Borah, Warm working as a potential substitute for hot working of austenitic steel in selected applications. Mater. Perform. Char. (2019). https://doi.org/10.1520/MPC20190021

    Article  Google Scholar 

  5. B. Aashranth, G. Shankar, M.A. Davinci, D. Samantaray, U. Borah, S. Suwas, The effect of crystallographic orientation and interfaces on thermo-mechanical softening of a martensitic steel. J. Mater. Res. 36, 2742 (2021). https://doi.org/10.1557/s43578-021-00141-5

    Article  CAS  Google Scholar 

  6. M.A. Davinci, D. Samantaray, U. Borah, S.K. Albert, A.K. Bhaduri, Influence of processing parameters on hot workability and microstructural evolution in a carbon–manganese–silicon steel. Mater. Des. 88, 567–576 (2015)

    Article  Google Scholar 

  7. B. Aashranth, D. Samantaray, S. Kumar, A. Dasgupta, U. Borah, S.K. Albert, A.K. Bhaduri, Flow softening index for assessment of dynamic recrystallization in an Austenitic Stainless Steel. J. Mater. Eng. Perform. (2017). https://doi.org/10.1007/s11665-017-2757-9

    Article  Google Scholar 

  8. D. Samantaray, S. Mandal, A.K. Bhaduri, Optimization of hot working parameters for thermo-mechanical processing of modified 9Cr–1Mo (P91) steel employing dynamic materials model. Mater. Sci. Eng. 528, 5204–5211 (2011)

    Article  CAS  Google Scholar 

  9. M. Rout, R. Ranjan, S.K. Pal, S.B. Singh, EBSD study of microstructure evolution during axisymmetric hot compression of 304LN stainless steel. Mater. Sci. Eng. A. 711, 378–388 (2018)

    Article  CAS  Google Scholar 

  10. T. Maki, K. Tsuzaki, I. Tamura, The morphology of microstructure composed of lath martensites in steels. Trans. ISIJ. 20, 207–214 (1980)

    Article  CAS  Google Scholar 

  11. F. Barcelo, J.-L. Bechade, FournierOrientation relationship in various 9%Cr ferritic/martensitic steels–EBSD comparison between Nishiyama-Wassermann, Kurdjumov-Sachs and Greninger-Troiano. Phase Transit. 83, 601 (2010). https://doi.org/10.1080/01411594.2010.502054

    Article  CAS  Google Scholar 

  12. C. Cayron, B. Artaud, L. Briottet, Reconstruction of parent grains from EBSD data. Mater. Charact. 57(4–5), 386–401 (2006)

    Article  CAS  Google Scholar 

  13. L. Germain, N. Gey, M. Humbert, Reconstruction of deformed parent grains from microstructure inherited by phase transformations. Scr. Mater. 158, 91–94 (2019). https://doi.org/10.1016/j.scriptamat.2018.08.042

    Article  CAS  Google Scholar 

  14. A. Brust, E. Payton, T. Hobbs, V. Sinha, V. Yardley, S. Niezgoda, Probabilistic reconstruction of austenite microstructure from electron backscatter diffraction observations of martensite. Microsc. Microanal. 27, 1035–1055 (2021). https://doi.org/10.1017/S1431927621012484

    Article  CAS  Google Scholar 

  15. ASTM E112–13, Standard Test Methods for Determining Average Grain Size, Developed by Subcommittee E04.08 on Grain Size (ASTM International, West Conshohocken, PA, 2013). https://doi.org/10.1520/E0112-13

  16. A. Bonyára, J. Renkób, D. Kovácsb, P.J. Szabób, Understanding the mechanism of Beraha-I type color etching: Determination of the orientation dependent etch rate, layer refractive index and a method for quantifying the angle between surface normal and the 〈100〉, 〈111〉 directions for individual grains. Mater. Charact. (2019). https://doi.org/10.1016/j.matchar.2019.109844

    Article  Google Scholar 

  17. V.A. Yardley, S. Fahimi, E.J. Payton, Classification of creep crack and cavitation sites in tempered martensite ferritic steel microstructures using MTEX toolbox for EBSD. Mater. Sci. Technol. 31(5), 547–553 (2015). https://doi.org/10.1179/1743284714Y.0000000603

    Article  CAS  Google Scholar 

  18. A. Chatterjee, A. Ghosh, A. Moitra, A.K. Bhaduri, R. Mitra, D. Chakrabarti, The role of crystallographic orientation of martensitic variants on cleavage crack propagation. Mater. Sci. (2016). https://doi.org/10.48550/arXiv.1606.09474

    Article  Google Scholar 

  19. G.F.V. Voort, Tables of chemicals and etchants. Metallogr. Microstruct. (2004). https://doi.org/10.31399/asm.hb.v09.a0003764

    Article  Google Scholar 

  20. B. Beausir, J.J. Fundenberger, Analysis Tools for Electron and X-ray diffraction, ATEX - software, www.atex-software.eu, Université de Lorraine - Metz, 2017.

  21. C. Cayron, ARPGE: a computer program to automatically reconstruct the parent grains from electron backscatter diffraction data. J. Appl. Crystallogr. 40(6), 1183–1188 (2007)

    Article  CAS  Google Scholar 

  22. G.F. Vander Voot, Basic Guide to tint etching HSLA steel crankshafts, Met. Prog. (1985).

  23. C.J. Cogswell, C.J.R. Sheppard, Confocal differential interference contrast (DIC) microscopy: including a theoretical analysis of conventional and confocal DIC imaging. J. Microsc. 165(1), 81–101 (1992). https://doi.org/10.1111/j.1365-2818.1992.tb04307.x

    Article  Google Scholar 

  24. J. Götze, Application of Nomarski DIC and cathodoluminescence (CL) microscopy to building materials. Mater. Charact. 60, 594–602 (2009)

    Article  Google Scholar 

  25. P.J. Szabo, I. Kardos, Correlation between grain orientation and the shade of color etching. Mater. Charact. 61, 814–817 (2010)

    Article  CAS  Google Scholar 

  26. M. Nowell, S.I. Wright, J.O. Carpenter, Differentiating Ferrite and Martensite in Steel Microstructures Using Electron Backscatter Diffraction. In Proceedings of the Materials Science and Technology (MS&T), Pittsburgh, PA, USA, 25–29 October 2009; Mater. Sci. Technol. 933–943 (2009).

  27. X. Hao, X. Zhao, H. Chen, B. Huang, J. Ma, C. Wang, Y. Yang, Comparative study on corrosion behaviors of ferrite-pearlite steel with dual-phase steel in the simulated bottom plate environment of cargo oil tanks. J. Mater. Res. Technol. 12, 399–411 (2021)

    Article  CAS  Google Scholar 

  28. S.S. Babu, H.K.D.H. Bhadeshia, A direct study of grain boundary allotriomorphic ferrite crystallography. Mater. Sci. Eng. A. 142, 209 (1991)

    Article  Google Scholar 

  29. T. Remmerswaal, The influence of microstructure on the corrosion behaviour of Ferritic–Martensitic steel,M.Sc. thesis, Available from Delft University of Technology, Thesis completed August, 2015.

  30. A. Ray, S.K. Dhua, Microstructural manifestations in color: Some applications for steels. Mater. Charact. 37, 1–8 (1996)

    Article  CAS  Google Scholar 

  31. F. Hizazi, D. Srinivasan, B. Roy, P. Kumar, V. Jayaram, Micro-texture regions in rolled Ti-6Al-4V under polarized light. Scr. Mater. 213(15), 114588 (2022)

    Google Scholar 

  32. E. Beraha, Metallographic reagents based on sulfide films. Prakt. Metallogr. 7, 242–248 (1970)

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603012, India

    Mantosh Mandal, B. Aashranth, Dipti Samantaray & M. Vasudevan

  2. Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094, India

    Dipti Samantaray & M. Vasudevan

Authors
  1. Mantosh Mandal
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. B. Aashranth
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Dipti Samantaray
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. M. Vasudevan
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to B. Aashranth.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Appendices

Appendix 1

Optimization of Etchant Composition

The action of color etchants for steels involves a chemical reaction between the etchant and the steel, leading to the production and deposition of a thin film on the steel surface. For etchants containing metabisulfite salts (generally sodium metabisulfite or potassium metabisulfite) or thiosulfate salts, the metabisulfite anion reacts with the iron cations, leading to deposition of thin sulfide film on the steel [32]. In the present study, the active cation is metabisulfite, arising from the potassium metabisulfite salt. The remaining ingredients of the etchant are sulfamic acid and ammonium bifluoride, besides the solvent (water). All these ingredients are also present in Beraha’s sulfamic acid reagent [19]. The optimization carried out to obtain the present etchant involves changing the proportion of different ingredients.

Beraha’s original etchant contains metabisulfite, sulfamic acid and bifluoride in the ratio 6:4:(1–2). The variable ingredient is ammonium bifluoride. Ammonium bifluoride is often used as a substitute for hydrofluoric acid [19], indicating its high reactivity and corresponding severe etching action. The inclusion of ammonium bifluoride in Beraha’s etchant is inferred to increase the reactivity of the etchant. Due to the presence of Cr in the current steel, a more reactive etchant was considered to be more suitable.

In order to verify this, a series of etching compositions were prepared in the ratio 6:4:(0–6) (corresponding to potassium metabisulfite, sulfamic acid and ammonium bifluoride, respectively).

Identical specimens of the 9%Cr steel used in this study was etched with these etchants. The results from four significant compositions are shown in Fig. 

Fig. 11
figure 11

Microstructures of the 9%Cr steel obtained after etching with: a 6:4:0, b 6:4:2, c 6:4:4, d 6:4:6, where the ratio indicates quantity of potassium metabisulfite:sulfamic acid:ammonium bifluoride by weight

Full size image

11.

In the absence of ammonium bifluoride (Fig. 11a), the color film appeared uneven and inadequate to delineate boundaries. With addition of ammonium bifluoride in Beraha’s prescribed range (Fig. 11b), the microstructure was sharper, with martensitic boundaries being delineated. However, PAGBs were not sharply delineated. Upon adding more ammonium bifluoride to reach the 6:4:4 composition (Fig. 11c), the color obtained was uniform, and martensitic boundaries and PAGBs both being delineated. Still further addition of ammonium bifluoride led to an uneven etch, where some regions were sharply etched and others were unclear (Fig. 1d), while the macroscopic appearance suggested overetching.

On account of uniformity, the 6:4:4 composition was selected as being optimal. Further refinement was possible by preparing the etchant just before use, and ensuring complete solubility of the added salts. Towards this, the following order of mixing was found optimal: addition of potassium metabisulfite to warm water (~ 60 °C) and stirring to complete dissolution, followed by dissolution of sulfamic acid to prepare a clear solution. The requisite amount of ammonium bifluoride was added at the end.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Mandal, M., Aashranth, B., Samantaray, D. et al. Improvements in the Metallography of Ferritic–Martensitic Steels Through a Color Etching Procedure. Metallogr. Microstruct. Anal. 12, 49–61 (2023). https://doi.org/10.1007/s13632-022-00916-0

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s13632-022-00916-0

Keywords

Search

Navigation