Recent progress in visualization and digitization of coherent transformation structures and application in high-strength steel

Abstract

High-strength steels are mainly composed of medium- or low-temperature microstructures, such as bainite or martensite, with coherent transformation characteristics. This type of microstructure has a high density of dislocations and fine crystallographic structural units, which ease the coordinated matching of high strength, toughness, and plasticity. Meanwhile, given its excellent welding performance, high-strength steel has been widely used in major engineering constructions, such as pipelines, ships, and bridges. However, visualization and digitization of the effective units of these coherent transformation structures using traditional methods (optical microscopy and scanning electron microscopy) is difficult due to their complex morphology. Moreover, the establishment of quantitative relationships with macroscopic mechanical properties and key process parameters presents additional difficulty. This article reviews the latest progress in microstructural visualization and digitization of high-strength steel, with a focus on the application of crystallographic methods in the development of high-strength steel plates and welding. We obtained the crystallographic data (Euler angle) of the transformed microstructures through electron back-scattering diffraction and combined them with the calculation of inverse transformation from bainite or martensite to austenite to determine the reconstruction of high-temperature parent austenite and orientation relationship (OR) during continuous cooling transformation. Furthermore, visualization of crystallographic packets, blocks, and variants based on actual OR and digitization of various grain boundaries can be effectively completed to establish quantitative relationships with alloy composition and key process parameters, thereby providing reverse design guidance for the development of high-strength steel.

Keywords

high-strength steel / microstructure / visualization / digitization / quantification / mechanical properties

References

[1] Xie ZJ, Shang CJ, Wang XL, Wang XM, Han G, Misra RDK. Recent progress in third-generation low alloy steels developed under M3 microstructure control. Int. J. Miner. Metall. Mater., 2020, 27(1): 1,

[2] Dong H, Sun XJ, Cao WQ, Liu ZD, Wang MQ, Weng YQ. Weng YQ, Dong H, Gan Y. On the performance improvement of steels through M3 structure control. Advanced Steels: The Recent Scenario in Steel Science and Technology, 2011 Beijing Springer-Verlag Berlin Heidelberg and Metallurgical Industry Press 35,

[3] Yu YS, Hu B, Gao ML, et al.. Determining role of heterogeneous microstructure in lowering yield ratio and enhancing impact toughness in high-strength low-alloy steel. Int. J. Miner. Metall. Mater., 2021, 28(5): 816,

[4] G.H. Gao, M. Liu, X.L. Gui, et al., Heterogenous structure and formation mechanism of white and brown etching layers in bainitic rail steel, Acta Mater., 250(2023), art. No. 118887.

[5] Sun XJ, Yuan SF, Xie ZJ, Dong LL, Shang CJ, Misra RDK. Microstructure-property relationship in a high strength-high toughness combination ultra-heavy gauge offshore plate steel: The significance of multiphase microstructure. Mater. Sci. Eng. A, 2017, 689: 212,

[6] Xie ZJ, Shang CJ, Zhou WH, Wu BB. Effect of retained austenite on ductility and toughness of a low alloyed multiphase steel. Acta Metall. Sin., 2016, 52(2): 224

[7] Han P, Liu ZP, Xie ZJ, et al.. Influence of band microstructure on carbide precipitation behavior and toughness of 1 GPa-grade ultra-heavy gauge low-alloy steel. Int. J. Miner. Metall. Mater., 2023, 30(7): 1329,

[8] Morito S, Tanaka H, Konishi R, Furuhara T, Maki T. The morphology and crystallography of lath martensite in Fe–C alloys. Acta Mater., 2003, 51(6): 1789,

[9] Kitahara H, Ueji R, Tsuji N, Minamino Y. Crystallographic features of lath martensite in low-carbon steel. Acta Mater., 2006, 54(5): 1279,

[10] Takayama N, Miyamoto G, Furuhara T. Effects of transformation temperature on variant pairing of bainitic ferrite in low carbon steel. Acta Mater., 2012, 60(5): 2387,

[11] You Y, Shang CJ, Nie WJ, Subramanian S. Investigation on the microstructure and toughness of coarse grained heat affected zone in X-100 multi-phase pipeline steel with high Nb content. Mater. Sci. Eng. A, 2012, 558: 692,

[12] Wang XL, Wang ZQ, Dong LL, Shang CJ, Ma XP, Subramanian SV. New insights into the mechanism of cooling rate on the impact toughness of coarse grained heat affected zone from the aspect of variant selection. Mater. Sci. Eng. A, 2017, 704: 448,

[13] Miyamoto G, Takayama N, Furuhara T. Accurate measurement of the orientation relationship of lath martensite and bainite by electron backscatter diffraction analysis. Scripta Mater., 2009, 60(12): 1113,

[14] Kawata H, Sakamoto K, Moritani T, Morito S, Furuhara T, Maki T. Crystallography of ausformed upper bainite structure in Fe–9Ni–C alloys. Mater. Sci. Eng. A, 2006, 438–440: 140,

[15] Suikkanen PP, Cayron C, DeArdo AJ, Karjalainen LP. Crystallographic analysis of isothermally transformed bainite in 0.2C–2.0Mn–1.5Si–0.6Cr steel using EBSD. J. Mater. Sci. Technol, 2013, 29(4): 359,

[16] Morito S, Huang X, Furuhara T, Maki T, Hansen N. The morphology and crystallography of lath martensite in alloy steels. Acta Mater., 2006, 54(19): 5323,

[17] Morito S, Edamatsu Y, Ichinotani K, et al.. Quantitative analysis of three-dimensional morphology of martensite packets and blocks in iron-carbon-manganese steels. J. Alloys Compd., 2013, 577: S587,

[18] Miyamoto G, Iwata N, Takayama N, Furuhara T. Variant selection of lath martensite and bainite transformation in low carbon steel by ausforming. J. Alloys Compd., 2013, 577: S528,

[19] Stormvinter A, Miyamoto G, Furuhara T, Hedström P, Borgenstam A. Effect of carbon content on variant pairing of martensite in Fe–C alloys. Acta Mater., 2012, 60(20): 7265,

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

[21] Cayron C. ARPGE: A computer program to automatically reconstruct the parent grains from electron backscatter diffraction data. J. Appl. Crystallogr., 2007, 40: 1183,

[22] Miyamoto G, Iwata N, Takayama N, Furuhara T. Mapping the parent austenite orientation reconstructed from the orientation of martensite by EBSD and its application to ausformed martensite. Acta Mater., 2010, 58(19): 6393,

[23] Germain L, Gey N, Mercier R, Blaineau P, Humbert M. An advanced approach to reconstructing parent orientation maps in the case of approximate orientation relations: Application to steels. Acta Mater., 2012, 60(11): 4551,

[24] Abbasi M, Nelson TW, Sorensen CD, Wei LY. An approach to prior austenite reconstruction. Mater. Charact., 2012, 66: 1,

[25] D.J. Sun, Z. Zhou, K. Zhang, et al., Novel reconstruction approaches of austenitic annealing twin boundaries and grain boundaries of ultrafine grained prior austenite, Mater. Des., 227(2023), art. No. 111692.

[26] Kang S, Speer JG, Regier RW, Nako H, Kennett SC, Findley KO. The analysis of bainitic ferrite microstructure in microalloyed plate steels through quantitative characterization of intervariant boundaries. Mater. Sci. Eng. A, 2016, 669: 459,

[27] C.J. Shang, X.C. Li, and X.L. Wang, Development of high performance steel for marine engineering II — Digital characterization of gene and microstructure for iron and steel materials, Angang Technol., (2018), No. 2, p. 1.

[28] Li XC, Zhao JX, Cong JH, et al.. Machine learning guided automatic recognition of crystal boundaries in bainitic/martensitic alloy and relationship between boundary types and ductile-to-brittle transition behavior. J. Mater. Sci. Technol., 2021, 84: 49,

[29] Lambert-Perlade A, Gourgues AF, Pineau A. Austenite to bainite phase transformation in the heat-affected zone of a high strength low alloy steel. Acta Mater., 2004, 52(8): 2337,

[30] Wang XL, Wang ZQ, Ma XP, et al.. Analysis of impact toughness scatter in simulated coarse-grained HAZ of E550 grade offshore engineering steel from the aspect of crystallographic structure. Mater. Charact., 2018, 140: 312,

[31] Morito S, Yoshida H, Maki T, Huang X. Effect of block size on the strength of lath martensite in low carbon steels. Mater. Sci. Eng. A, 2006, 438–440: 237,

[32] Rancel L, Gómez M, Medina SF, Gutierrez I. Measurement of bainite packet size and its influence on cleavage fracture in a medium carbon bainitic steel. Mater. Sci. Eng. A, 2011, 530: 21,

[33] Shibata A, Nagoshi T, Sone M, Morito S, Higo Y. Evaluation of the block boundary and sub-block boundary strengths of ferrous lath martensite using a micro-bending test. Mater. Sci. Eng. A, 2010, 527(29–30): 7538,

[34] Du C, Hoefnagels JPM, Vaes R, Geers MGD. Block and sub-block boundary strengthening in lath martensite. Scr. Mater., 2016, 116: 117,

[35] X.C. Li, J.X. Zhao, L.L. Dong, et al., The significance of coherent transformation on grain refinement and consequent enhancement in toughness, Materials, 13(2020), No. 22, art. No. 5095.

[36] Wu BB, Wang XL, Wang ZQ, et al.. New insights from crystallography into the effect of refining prior austenite grain size on transformation phenomenon and consequent mechanical properties of ultra-high strength low alloy steel. Mater. Sci. Eng. A, 2019, 745: 126,

[37] Wu BB, Wang ZQ, Yu YS, Wang XL, Shang CJ, Misra RDK. Thermodynamic basis of twin-related variant pair in high strength low alloy steel. Scripta Mater., 2019, 170: 43,

[38] Wu BB, Wang ZQ, Wang XL, Xu WS, Shang CJ, Misra RDK. Toughening of martensite matrix in high strength low alloy steel: Regulation of variant pairs. Mater. Sci. Eng. A, 2019, 759: 430,

[39] Wu BB, Huang S, Wang ZQ, et al.. Crystallography analysis of toughness in high strength ultra-heavy plate steel. Mater. Lett, 2019, 250: 55,

[40] Yu YS, Wang ZQ, Wu BB, et al.. Tailoring variant pairing to enhance impact toughness in high-strength low-alloy steels via trace carbon addition. Acta Metall. Sin., 2021, 34(6): 755,

[41] S. Huang, Y.S. Yu, Z.Q. Wang, et al., Crystallographic insights into the role of nickel on hardenability of wear-resistant steels, Mater. Lett., 306(2022), art. No. 130961.

[42] Liu ZC, Wang XL, Yu YS, Shang CJ. Study on toughening mechanism of high strength steel and its relationship with substructure. J. Iron Steel Res., 2020, 32(12): 1093

[43] J.L. Wang, F.J. Guo, Z.Q. Wang, Z.J. Xie, C.J. Shang, and X.L. Wang, Influence of centerline segregation on the crystallographic features and mechanical properties of a high-strength low-alloy steel, Mater. Lett., 267(2020), art. No. 127512.

[44] Miyamoto G, Iwata N, Takayama N, Furuhara T. Quantitative analysis of variant selection in ausformed lath martensite. Acta Mater., 2012, 60(3): 1139,

[45] Z.C. Liu, J. Yang, H. Guo, X.L. Wang, and C.J. Shang, Crystal-lographic study on deformed bainite structure of ultra-high strength steel and its relationship with strength and ductile–brittle transition temperature, Mater. Lett., 326(2022), art. No. 132947.

[46] Bernier N, Bracke L, Malet L, Godet S. Crystallographic reconstruction study of the effects of finish rolling temperature on the variant selection during bainite transformation in C–Mn high-strength steels. Metall. Mater. Trans. A, 2014, 45(13): 5937,

[47] M.Y. Sun, X.L. Wang, Z.Q. Wang, et al., The critical impact of intercritical deformation on variant pairing of bainite/martensite in dual-phase steels, Mater. Sci. Eng. A, 771(2020), art. No. 138668.

[48] Li XD, Ma XP, Subramanian SV, Shang CJ, Misra RDK. Influence of prior austenite grain size on martensite-austenite constituent and toughness in the heat affected zone of 700MPa high strength linepipe steel. Mater. Sci. Eng. A, 2014, 616: 141,

[49] Miao CL, Liu ZW, Guo H, Shang CJ, Fu YH, Wang XX. Effect of Nb content and heat input on coarse-grained welding heat affected zone of X80 pipeline steels. Trans. Mater. Heat Treat., 2012, 33(1): 99

[50] Ma XP, Li XD, Langelier B, Gault B, Subramanian S, Collins L. Effects of carbon variation on microstructure evolution in weld heat-affected zone of Nb–Ti microalloyed steels. Metall. Mater. Trans. A, 2018, 49(10): 4824,

[51] Wan X, Zhou B, Nune KC, Li Y, Wu K, Li G. In-situ microscopy study of grain refinement in the simulated heat-affected zone of high-strength low-alloy steel by TiN particle. Sci. Technol. Weld. Joining, 2017, 22(4): 343,

[52] X.G. Zhang, Y.J. Ren, J. Zhang, et al., Effects of prior austenite grain size on reversion kinetics of different crystallographic austenite in a low carbon steel, Mater. Charact., 190(2022), art. No. 112025.

[53] X.L. Wang, Z.Q. Wang, A.R. Huang, et al., Contribution of grain boundary misorientation to intragranular globular austenite reversion and resultant in grain refinement in a high-strength low-alloy steel, Mater. Charact., 169(2020), art. No. 110634.

[54] Zhang XG, Miyamoto G, Toji Y, Nambu S, Koseki T, Furuhara T. Orientation of austenite reverted from martensite in Fe–2Mn–1.5Si–0.3C alloy. Acta Mater., 2018, 144: 601,

[55] X.L. Wang, Z.J. Xie, Z.Q. Wang, Y.S. Yu, L.Q. Wu, and C.J. Shang, Crystallographic study on microstructure and impact toughness of coarse grained heat affected zone of ultra-high strength steel, Mater. Lett., 323(2022), art. No. 132552.

[56] Wang XL, Ma XP, Wang ZQ, et al.. Carbon microalloying effect of base material on variant selection in coarse grained heat affected zone of X80 pipeline steel. Mater. Charact., 2019, 149: 26,

[57] You Y, Shang CJ, Chen L, Subramanian S. Investigation on the crystallography of the transformation products of reverted austenite in intercritically reheated coarse grained heat affected zone. Mater. Des., 2013, 43: 485,

[58] You Y, Shang CJ, Subramanian S. Effect of Ni addition on toughness and microstructure evolution in coarse grain heat affected zone. Met. Mater. Int., 2014, 20(4): 659,

[59] Wang ZQ, Wang XL, Nan YR, et al.. Effect of Ni content on the microstructure and mechanical properties of weld metal with both-side submerged arc welding technique. Mater. Charact., 2018, 138: 67,

[60] Niessen F, Nyyssönen T, Gazder AA, Hielscher R. Parent grain reconstruction from partially or fully transformed microstructures in MTEX. J. Appl. Crystallogr, 2022, 55: 180,

[61] Asherloo M, Wu ZH, Sabisch JEC, Ghamarian I, Rollett AD, Mostafaei A. Variant selection in laser powder bed fusion of non-spherical Ti–6Al–4V powder. J. Mater. Sci. Technol., 2023, 147: 56,

[62] Y. Zhang, R.L. Xin, K. Wang, and Q. Liu, Variant selection of a precipitates formed at β triple junctions in titanium alloy, Mater. Charact., 189(2022), art. No. 111975.

[63] C. Paramatmuni, Y. Guo, P.J. Withers, and F.P.E. Dunne, A three-dimensional mechanistic study of the drivers of classical twin nucleation and variant selection in Mg alloys: A mesoscale modelling and experimental study, Int. J. Plast., 143(2021), art. No. 103027.

[64] Ma XP, Miao CL, Langelier B, Subramanian S. Suppression of strain-induced precipitation of NbC by epitaxial growth of NbC on pre-existing TiN in Nb–Ti microalloyed steel. Mater. Des., 2017, 132: 244,

[65] S.V. Subramanian, X.P. Ma, W.J. Nie, and X.B. Zhang, Application of nano-scale precipitate engineering of TiN–NbC composite in 32mm K60-E2 grade plate rolling, [in] HSLA Steels 2015, Microalloying 2015 & Offshore Engineering Steels: Conference Proceedings, Hangzhou, 2015, p. 211.

[66] Ma XP, Langelier B, Gault B, Subramanian S. Effect of Nb addition to Ti-bearing super martensitic stainless steel on control of austenite grain size and strengthening. Metall. Mater. Trans. A, 2017, 48(5): 2460,

[67] Schino AD, Nunzio PED. Effect of Nb microalloying on the heat affected zone microstructure of girth welded joints. Mater. Lett., 2017, 186: 86,

[68] Fossaert C, Rees G, Maurickx T, Bhadeshia HKDH. The effect of niobium on the hardenability of microalloyed austenite. Metall. Mater. Trans. A, 1995, 26(1): 21,

[69] Rees GI, Perdrix J, Maurickx T, Bhadeshia HKDH. The effect of niobium in solid solution on the transformation kinetics of bainite. Mater. Sci. Eng. A, 1995, 194(2): 179,