Sulfur is present in solid steel as manganese sulfide (MnS) inclusions. Their volume fraction, size, shape and distribution depend on the suphur content, oxygen content, solidification rate, degree of hot and cold deformation and hot working temperatures.
These MnS inclusions have several effects on the processing and properties of steel. Mainly these effects are detrimental, as these inclusions are more plastic than steel and, hence, during deformation they act as crack initiation sites and zones of weakness.
Sulfur is detrimental to ductility, toughness, formability, weldability and corrosion reisitance. However, sulfur is beneficial to machinability.
Sufficient manganese must be present in the steel to prevent the formation of iron sulfide, which is highly detrimental to hot workability and leads to severe cracking during hot rolling (hot shortness).
Elongated MnS inclusions
See Also
- Secondary Steelmaking > Secondary Steelmaking: Overview
References
- Turkdogan, ET, Fundamentals of Steelmaking, The Institute of Materials, 1 86125 004 5
Authors/Contributors:
- Henri Gaye, Graduate Institute of Ferrous Technology, POSTECH
- Hae-Geon Lee, POSTECH
- Christian Bernhard, CD-Labor für metallurgische Grundlagen von Stranggießprozessen - Lehrstuhl für Metallurgie,
Montanuniversität Leoben
- Pär Jönsson, KTH Royal Institute of Technology, Stockholm
- Claire Davis, School of Metallurgy & Materials,
University of Birmingham