Recent advancements in manganese steels - A review

This article reviews the current state of the art in understanding manganese steels. The standard manganese steel (Hadfield's Manganese) has roughly 12% manganese and 1.2% carbon. This approximate 10 to 1 ratio from Hadfield's work. Then there is High manganese steels with 18-31% Mn with higher carbon content upto 1.9%, higher manganese grades require elevated carbon levels in order to achieve the desired increase in service life. And other being Lean manganese steels with 5-8% Mn, 1%C and 1.5% Mo to help stabilize the austenite. Medium Mn steels had been investigated due to their excellent balance between material cost and mechanical properties. Consisting of a single alpha' martensite phase in hot and cold rolled states and multiphases after inter-critical annealing. The steels exhibit high strength and good ductility due to transformation induced plasticity occurring in retained gamma gamma(R), whose volume fraction is approximately 0.2-0.4. There another deformation mechanism called twinning induced plasticity (TWIP) enhances certain Manganese steels. TWIP steels exhibit very high strain hardening rate due to the deformation twins taking advantages of dynamic Hall-Petch effect. In TWIP steels the manganese content varies between 20 and 30%. In spite of some very desirable properties, it also poses a challenge in materials production. Reducing Mn content in TWIP steels and addition of Al reduced the tendency for delayed cracking. Since the Mn content in TWIP steels influences the stacking fault energy (SFE) which plays major role deformation mechanism. This review concludes by suggesting fundamental research needs to promote the design of manganese steels with improved properties and performance. (C) 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International conference on Materials and Manufacturing Methods.