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Flanges
Welding Neck Flange Bores, Pipe Flanges and Flanged Fittings,
Carbon and Stainless Steel Welding,Flange Supplier, Welding
Neck flange, Slip-On flange,Blind flange Exporter, Welding Neck
flange, Manufacturer, Forged Flanges, supplier, Raised- Face
Flanges, Socket Weld flange, Traders, Threaded flange, Back-Up
Flange, Blind flange, Maker, Stainless Steel Pipe Flange, Socket
weld Flange, carbon steel plate Flange, Exporter, carbon steel
Flange, Windsro Exportes, All Flange Exports From india
Weld Neck :
WELDING
NECK FLANGES are distinguished from other
types by their long tapered hub and gentle transition
of thickness in the region of the butt weld joining
them to the pipe. The long tapered hub provides
an important reinforcement of the flange proper
from the standpoint of strength and resistance
to dishing. The smooth transition from flange
thickness to pipe wall thickness effected by the
taper is extremely beneficial under conditions
of repeated bending, caused by line expansion
or other variable forces and produces an endurance
strength of welding neck flanged assemblies equivalent
to that of a butt welded joint between pipes,
which, in practice, is the same as that of unwelded
pipe. Thus this type of flange is preferred for
every severe service condition, whether this results
from high pressure or from sub-zero or elevated
temperature, and whether loading conditions are
substantially constant or fluctuate between wide
limits. |
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Slip-On :
SLIP-ON
FLANGES continue to be preferred to welding
neck flanges by many users on account of their
initially lower cost, the reduced accuracy required
in cutting the pipe to length, and the somewhat
greater ease of alignment of the assembly; however
their final installed cost is probably not much,
if any, less than that of welding neck flanges.
Their calculated strength under internal pressure
is approximately two-thirds that of welding neck
flanges, and their life under fatigue is about
one-third that of the latter. For these reasons,
slip-on flanges are limited to sizes ½"
to 2 ½" in the 1500 lb standard and are
not shown in the 2500lb standard. |
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Blind :
BLIND
FLANGES are used to blank off the ends
of piping, valves and pressure vessel opening.
From the standpoint of internal pressure and bolt
loading, blind flanges, particularly in the larger
sizes, are the most highly stressed of all flange
types; however, since the maximum stresses in
a blind flange are bending stresses at the center,
they can safely be permitted to be higher than
in other types of flanges. |
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Lap - Joint :
LAP JOINT FLANGES are primarily
employed with lap joint stubs, the combined initial
cost of the two items being approximately one-third
higher than that of comparable welding neck flanges.
Their pressure-holding ability is little, if any,
better than that of slip-on flanges and the fatigue
life of the assembly is only one-tenth that of
welding neck flanges. The chief use of lap joint
flanges in carbon or low alloy steel piping systems
is in services necessitating frequent dismantling
for inspection and cleaning and where the ability
to swivel flanges and to align bolt holes materially
simplifies the erection of large diameter or unusually
stiff piping. Their use at points where severe
bending stress occurs should be avoided. |
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Threaded :
THREADED FLANGES are confined
to special applications. Their chief merit lies
in the fact that they can be assembled without
welding this explains their use in extremely high
pressure services, particularly at or near atmospheric
temperature, where alloy steel is essential for
strength and where the necessary post weld heat
treatment is impractical. Threaded flanges are
unsuited for conditions involving temperature
or bending stresses of any magnitude, particularly
under cyclic conditions, where leakage through
the threads may occur in relatively few cycles
of heating or stress; sea welding is sometimes
employed to overcome this, but cannot be considered
as entirely satisfactory. |
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Socket Weld :
SOCKET WELDING FLANGES were initially
developed for use on small size high pressure
piping. When provided with an internal weld, their
static strength is equal to, but their fatigue
strength 50% greater than double welding slip-on
flanges. Smooth bore conditions can readily be
attained (by grinding the internal weld) without
having to bevel the flange face and, after welding,
to reface the flange as would be required with
slip-on flanges. The internally welded socket
type flange is popular in chemical process piping
for this reason. |
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Orifice :
ORIFICE
FLANGES are widely used in conjunction
with orifice meters for measuring the rate of
flow of liquids and gases. They are basically
the same as standard welding neck and slip-on
flanges except for the provision of radial, tapped
holes in the flange ring for meter connections
and additional bolts to act as jack screws to
facilitate separating the flanges for inspection
or replacement of the orifice plate. In choosing
the type of orifice flange, the considerations
affecting the choice of welding neck and slip-on
standard flanges apply with equal force. |
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