Alloy steel pipe are most commonly referred as Chrome Moly Steel
pipe. These pipe are alloyed with a variety of elements including
chrome, molybdenum and vanadium between 1.00% – 0.50%.
Further Alloy Steel pipe are divided as follows:
Low Alloy Steel pipe
High Alloy Steel pipe
Alloy Steel Seamless pipe
Alloy Steel Welded pipe
Apart
from chrome molybdenum and vanadium, carbon elements like cobalt,
nickel, niobium, titanium, tungsten, & zirconium can be added to
attain respective alloying effect. These elements are added due to
individual elemental benefits. Elements with a lower percentage i.e.
less that 5% are added to increase the strength and harden ability and
in larger % to achieve special properties like corrosion resistance,
high temperature sustainability, high yield and impact results. In the
field of piping industry, every steel pipe is an alloy pipe, may it be
carbon alloy pipe or chrome moly alloy steel pipe, but not all steel
pipe are called as alloy steel pipe. In general, a pipe is referred as
an alloy steel pipe when content of Manganese – 1.65%, Silicon – 0.6%
& copper 0.6 % exceeds the limit prescribed.
Heat treatment
Alloy
Steel pipe are heat treated to achieve mechanical properties as per the
desired alloying element. Below are some of the types of heat
treatment.