Effects of silicon carbide contents on the microstructure of sintered steels

Silicon and carbon are common alloying elements in wrought steel production. A judicious content of silicon can prevent carbide precipitation. So silicon is commonly used in the production of carbide-free bainitic steel, which is one of advanced high strength steels. It was found previously that both silicon and carbon elements from silicon carbide additives can be alloyed to form iron-based powder compacts via sintering process. In this study, sintered steels were produced from mixtures of pre-alloyed Fe-0.50Mo-0.15Mn powder and various silicon carbide contents (1.0, 2.0, 3.0, and 4.0 wt.%) using ‘press and sinter’ process. Microstructures of sintered steels changed in accordance with added silicon carbide content. The microstructure consisting of ferrite plate and martensite/austenite constituent in the low silicon carbide-added steel was changed to the microstructure with martensite matrix in high silicon carbideadded steel. Surprisingly, diffusional phase transformations resulting in the formations of pearlite and inverse bainite were occurred prior to diffusionless martensitic transformation in high silicon carbide-added steel. The ultimate tensile strength and hardness of the studied sintered steels increased with increasing martensite volume fraction but dropped with the presence of grain boundary carbide networks.

[1]  S. Zwaag,et al.  Fundamentals and application of solid-state phase transformations for advanced high strength steels containing metastable retained austenite , 2021, Materials Science and Engineering: R: Reports.

[2]  Ba Li,et al.  Effects of continuous cooling rate on morphology of granular bainite in pipeline steels , 2020 .

[3]  Thorsten Staudt,et al.  Classification of Bainitic Structures Using Textural Parameters and Machine Learning Techniques , 2020 .

[4]  Bo Gao,et al.  Low Temperature Deformation Induced Microstructure Refinement and Consequent Ultrahigh Toughness of a 20Mn2SiCrNi Bainitic Steel , 2019 .

[5]  A. P. Tschiptschin,et al.  Improvement of wear resistance in a pearlitic rail steel via quenching and partitioning processing , 2019, Scientific Reports.

[6]  Zhengyi Jiang,et al.  Transformation Behavior and Properties of Carbide‐Free Bainite Steels with Different Si Contents , 2018, steel research international.

[7]  Thierry Iung,et al.  New developments of advanced high-strength steels for automotive applications , 2018, Comptes Rendus Physique.

[8]  N. Prabhu,et al.  Effect of austempering temperature and time on mechanical properties of SAE 9260 steel , 2018 .

[9]  J. Sietsma,et al.  The role of silicon in carbon partitioning processes in martensite/austenite microstructures , 2017 .

[10]  Guang Xu,et al.  Bainitic Transformation and Properties of Low Carbon Carbide-Free Bainitic Steels with Cr Addition , 2017 .

[11]  H. Matsuda,et al.  Effect of Si on the acceleration of bainite transformation by pre-existing martensite , 2016 .

[12]  S. Primig,et al.  Structural characterization of “carbide-free” bainite in a Fe–0.2C–1.5Si–2.5Mn steel , 2015 .

[13]  G. Gao,et al.  A carbide-free bainite/martensite/austenite triplex steel with enhanced mechanical properties treated by a novel quenching-partitioning-tempering process , 2013 .

[14]  Kebing Zhang,et al.  A new effect of retained austenite on ductility enhancement in high strength bainitic steel , 2012 .

[15]  Patricia Verleysen,et al.  Advanced high strength steels for automotive industry , 2012 .

[16]  Kebing Zhang,et al.  A new effect of retained austenite on ductility enhancement in high-strength quenching–partitioning–tempering martensitic steel , 2011 .

[17]  H. Bhadeshia,et al.  Carbide-Free Bainite: Compromise between Rate of Transformation and Properties , 2010 .

[18]  Hasler,et al.  The microstructure of continuously cooled tough bainitic steel , 2010 .

[19]  H. Bhadeshia,et al.  Nanostructured bainite , 2019, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[20]  B. Bai,et al.  Very high cycle fatigue mechanism of carbide-free bainite/martensite steel micro-alloyed with Nb , 2009 .

[21]  E. Pereloma,et al.  Mechanical Behavior and Microstructure of High Carbon Si–Mn–Cr Steel with Trip Effect , 2009 .

[22]  H. Bhadeshia,et al.  Influence of silicon on cementite precipitation in steels , 2008 .

[23]  D. Matlock,et al.  The "quenching and partitioning" process: background and recent progress , 2005 .

[24]  S. Zając,et al.  Characterisation and Quantification of Complex Bainitic Microstructures in High and Ultra-High Strength Linepipe Steels , 2005 .

[25]  Nikhilesh Chawla,et al.  Microstructure and mechanical behavior of porous sintered steels , 2005 .

[26]  F. Caballero,et al.  The Role of Retained Austenite on Tensile Properties of Steels with Bainitic Microstructures , 2005 .

[27]  G. Voort,et al.  A Study of Selective Etching of Carbides in Steel , 2004, Microscopy and Microanalysis.

[28]  B. C. De Cooman,et al.  Structure–properties relationship in TRIP steels containing carbide-free bainite , 2004 .

[29]  H. Bhadeshia,et al.  Low temperature bainite , 2003 .

[30]  Francisca García Caballero,et al.  Very strong low temperature bainite , 2002 .

[31]  S. Cescotto,et al.  Quantitative description of MC, M2C, M6C and M7C3 carbides in high speed steel rolls , 2001 .

[32]  Tsutomu Iida,et al.  Stretch-flangeability of a High-strength TRIP Type Bainitic Sheet Steel , 2000 .

[33]  P. Hodgson,et al.  Hot deformation characteristics of Si-Mn TRIP steels with and without Nb microalloy additions , 1995 .

[34]  H. Andren,et al.  MICROSTRUCTURE OF GRANULAR BAINITE , 1988 .

[35]  V. Bišs,et al.  Martensite and retained austenite in hot-rolled, low-carbon bainitic steels , 1971 .