Red-short, hot-short refers to brittleness of steels at red-hot temperatures. It is often caused by high sulfur levels, in which case it is also known as sulfur embrittlement.

Description

Iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...

or steel, when heated to above 900 °F (460 °C), glows with a red color. The color of heated iron changes predictably (due to black-body radiation) from dull red through orange and yellow to white, and can be a useful indicator of its temperature. Good quality iron or steel at and above this temperature becomes increasingly

malleable Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stres ...

and plastic. Iron or steel having too much sulfur, on the other hand, becomes crumbly and brittle. This is due to the sulfur forming iron sulfide/iron mixtures in the grain boundaries of the metal which have a lower melting point than the steel.Deev et al. (May–June 1982)
"Role of iron sulfide in the formation of cracks in weld joints"
''Materials Science'', Vol. 18, No. 3, pp. 109–112. When the steel is heated up and worked, the mechanical energy added to the workpiece increases the temperature further. The

iron sulfide Iron sulfide or Iron sulphide can refer to range of chemical compounds composed of iron and sulfur. Minerals By increasing order of stability: * Iron(II) sulfide, FeS * Greigite, Fe3S4 (cubic) * Pyrrhotite, Fe1−xS (where x = 0 to 0.2) (monocli ...

(FeS) or iron/iron sulfide alloy (which has an even lower melting point)Sachinath Mitra.
High-pressure geochemistry and mineral physics
'. p. 1028. begins to melt, and the steel starts to separate at the grain boundaries. Steelmakers add

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

(Mn) to the steel when it is produced, to form

manganese sulfide Manganese(II) sulfide is a chemical compound of manganese and sulfur. It occurs in nature as the mineral alabandite (isometric), rambergite (hexagonal), and recently found browneite (isometric, with sphalerite-type structure, extremely rare, known ...

(MnS). Manganese sulfide inclusions have a higher melting point and do not concentrate at the grain boundaries. Thus, when the steel is later heated up and worked, the melting at the grain boundaries does not occur.

References

Metallurgy {{industry-stub