Increases strength and hardness; forms a carbide; increases hardenability;
lowers the transformation temperature range. When in sufficient quantity
produces an austenitic steel; always present in a steel to some extent
because it is used as a deoxidiser
Strengthens ferrite and raises the transformation temperature temperatures;
has a strong graphitising tendency. Always present to some extent,
because it is used with manganese as a deoxidiser
Increases strength and hardness; forms hard and stable carbides.
It raises the transformation temperature significantly when its content
exceeds 12%. Increases hardenability; amounts in excess of 12%, render
steel stainless. Good creep strength at high temperature.
Strengthens steel; lowers its transformation temperature range; increases
hardenability, and improves resistance to fatigue. Strong graphite forming
tendency; stabilizes austenite when in sufficient quantity. Creates
fine grains and gives good toughness.
Nickel And Chromium
Used together for austenitic stainless steels; each element counteracts
disadvantages of the other.
Forms hard and stable carbides; raises the transformation temperature
range, and tempering temperatures. Hardened tungsten steels resist
tempering up to 6000C
Strong carbide forming element, and also improves high temperature
creep resistance; reduces temper-brittleness in Ni-Cr steels. Improves
corrosion resistance and temper brittleness.
Strong carbide forming element; has a scavenging action and produces
clean, inclusion free steels. Can cause re-heat cracking when added to
chrome molly steels.
Strong carbide forming element. Not used on its own, but added as a
carbide stabiliser to some austenitic stainless steels.
Increases strength and hardnability, reduces ductility and toughness.
Increases machineability and corrosion resistance
Reduces toughness and strength and also weldabilty.
Sulphur inclusions, which are normally present, are taken into solution
near the fusion temperature of the weld. On cooling sulphides and
remaining sulphur precipitate out and tend to segregate to the grain boundaries
as liquid films, thus weakening them considerably. Such steel is
referred to as burned. Manganese breaks up these films into globules
of maganese sulphide; maganese to sulphur ratio > 20:1, higher carbon
and/or high heat input during welding > 30:1, to reduce extent of burning.