2. The main reasons behind
alloying the elements is to
increase various properties
such as
hardenability,corrosion
resistance,toughness,strengt
h,magnetic
properties,machinability & to
prevent brittleness.
3. About 2-5% Nickel is
added to steel to
improve toughness
And 12-20%to
increase corrosion
resistance
4.
5. Nickel steels are widely used for
parts subjected to fatigue and
impact load .
They possess greater tensile
strength together with considerable
ductility and toughness.
The most nickel steels contain 0.25
to 0.4 % Carbon and 1 to 5 % nickel.
These steels normally contain small
amounts of manganese to stabilise
the carbide phase.
6. Steels with high nickel content
are extremely tough and are
highly resistance to corrosion.
They also have low coefficient
of thermal expansion i.e. they
expand very little with the
change in temperature.