Hydrocarbon Processing - May 2021 - 31

Maintenance and Reliability
The crack then propagated through the
weld metal of Weld 1 toward the inner
surface of the shell.
In FIG. 5, a second weld can be seen between the reinforcement pad and the nozzle. There is also a gouge in the shell. Material has been removed from this location
and a small quantity deposited adjacent to
the gouge. Both this gouge and another
parallel gouge can be seen in FIG. 2 running
across the entire width of the material.
A microscopical examination of this
section revealed that all three parent materials were ferrite-pearlite microstructure. Weld 1 had been carried out from
the inside of the shell (FIG. 6A). It appears
that an initial tack weld was performed
to attach the reinforcement pad, and that
the cap was ground flush to the inside of
the shell. This weld has HAZ regions on
all three parent materials. The crack has
propagated through the main part of the
weld. FIG. 6B shows detail of the crack and
microstructure at the mouth of the crack.
Weld 2 is between the nozzle and the
reinforcement pad (FIG. 7A). There is a
feature that is likely to be lack of fusion

associated with the root pass on the reinforcement pad side of the weld (FIG. 7B).
Hardness results for Weld 1 found a
peak hardness of 258 HV5, which was associated with the HAZ of the tack weld
on the reinforcement pad parent material. Peak hardness in the HAZ associated
with the nozzle and shell parent materials
were 179 and 206 HV5, respectively. The
peak weld metal hardness measured 202
HV5 in the tack weld, 207 HV5 in the
subsequent root pass, and 194 HV5 in the
cap. The hardness results for Weld 1 are
detailed in TABLE 1.
The peak hardness associated with
Weld 2 was 280 HV5 in the HAZ adjacent
to the cap in the reinforcement pad parent material. The HAZ associated with
the root pass of this weld had a peak hardness of 232 HV5 in the reinforcement
pad parent material. The HAZ associated
with the nozzle parent material had a lower peak hardness of 203 HV5. The peak
hardness measured in the weld metal was
225 HV5 in the cap and 202 HV5 near to
the root. The hardness results for Weld 2
are detailed in TABLE 2.

FIG. 7. (A) Overview of Weld 2, which
was located between the nozzle and the
reinforcement pad; and (B) detail of the
lack of fusion at the reinforcement pad side
of the weld.

1.77''
4.5cm Pin

0.83''
2.1cm
0.94''
2.4cm
Pop-A-Plug P2
Duplex 2205

0.83''
2.1cm

Scheduled Maintenance
Leaking Tubes

Perfect Solution for Leaking Heat Exchanger Tubes!
Trusted by process plants around the world as the industry's leading tube leak solution, Pop-A-Plug Tube Plugs from Curtiss-Wright are
engineered for optimal performance throughout the life cycle of the heat exchanger. Controlled hydraulic installation eliminates welding and
time-consuming pre-/post-weld heat treatments that can cause damage to tubes, tube sheet ligaments, and joints. Pop-A-Plug Tube Plugs
are manufactured with ASME /ASTM certiﬁed materials.
*
*

Pressure rating 7000 PsiG (483 BarG)
Helium leak tight seal to 1 x 10

877.328.2107

-10

cc/sec

Wide range of sizes /materials to accommodate any application

100% lot tested to ensure unmatched quality

est-sales@curtisswright.com

cw-estgroup.com/hp

Hydrocarbon Processing | MAY 2021

http://www.cw-estgroup.com/hp

Hydrocarbon Processing - May 2021

Table of Contents for the Digital Edition of Hydrocarbon Processing - May 2021