Sulfur is practically not dissolved by Α iron , so it creates iron sulfide FeS which melts at the temperature of 1200 C.
At the temperature of 800-900 o C steel containing too much sulfur, there is not too plastic and brittle (so-called fragility of
red heat). At the temperature of 1000-1200 C (because FeS is then dissolved transiently in austenite) steel processes well.
Above the melting temperature of iron sulfide - 1200 o C, the steel is brittle and this phenomenon is called Hot brittleness
of names. The alloying addition of manganese, which forms manganese sulfide with sulfur MnS freezing at the temperature
of 1600 o C, reduces the effect of the fragility of the red embers. Sulfur can cause undesirable band structure, narrows down
the impact strength and weldability. It also has negative effects on the magnetic properties. Sulfur – apart from easy-machining
steels to which it is added intentionally, is practically undesirable in any other steel.
