Special Expansion Joints for Hot Blast Main Application
The designer of the blast furnace hot blast main faces
several unique challenges. The hot blast main is typically
a large diameter pipe subject to a number of thermal
expansion components. The expansion joint system
must be designed to accommodate thermal movements
in the X, Y and Z directions of the stove branch
connections, main and bustle pipe. Thermal movements
are due to variations in skin temperature caused by the
media as well as variations in the temperature of tie rods
and structures due to changes in ambient conditions.
Consideration must also be given to the forces and movements
imposed on the stove connections and structures
as well as stresses in the hot blast piping system. Finally,
the expansion joints must operate over the lengthy
blast furnace campaign with minimal maintenance required.
Senior Flexonics Pathway has pioneered the use of .125"
thick, high nickel-alloy bellows over the last 12 years.
The USS/ Kobe Steel Lorain Works #3 blast furnace
expansion joints are an example of this bellows design.
These bellows type expansion joints can take movement
in all directions while welded pipe type expansion joints
could take only axial movement. The high nickel alloy
bellows material offers superior resistance to chloride
stress corrosion cracking. Additionally, the .125" bellows
thickness allows relatively easy weld repair if necessary.
A plan view of the hot blast main layout at the
Lorain Works is shown on the back of this news release
for reference.
Senior Flexonics Pathway is facilitated to provide the
heavy wall bellows required for hot blast main service in
all sizes. Senior Flexonics Pathway engineers can also
provide pipe stress analysis and the engineering support
required to locate and specify guide and anchor requirements
for hot blast main applications. Our hot blast
main customers include Bethlehem Steel, USS, LTV and
many others. For more information about expansion joints
for hot blast main applications, contact Senior Flexonics
Pathway.