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FABRICATION OF JOINTS BETWEEN PUMP
BARRELS AND THE PRESSURE SHELL
OF THE ART
P. Patriarca
The ability to weld an accurately machined and
properly stress-relieved pump barret to a thick-
walled pressure shell without the need for finish
machining or subsequent stress relieving would
simplify considerably the assembly of the “north
head” of the ART. A design was suggested to
permit such a procedure, and a test was conducted
to evaluate the feasibility of the design.
The component parts of the joint used for the
test are shown in Fig. 3.4.7. The liner flange
is shown attached to the pump barrel sleeve,
which in turn was welded to the pump barrel. The
liner flange is also shown attached to a carbonsteel
pipe, .. which was in turn welded to a 2k-in.-
~
thick carbon-steel base plate. This auxfliary
weldment was intended to provide a degree of
restraint comparable to that to be expected from
the northhead expansion tank.
PERfOD ENDING JUNE 10, 1956
It is interesting to note that at least partial
relief of residual stresses was accomplished by
cutting the barrel assembly from the restraints
und soaking at 1SWF. This procedure resulted
in additional diametrical changes, which indicate
that some distortion will occur in the north head
in service that may be unacceptable.
Axial changes were also determined by mi-
crometer measurements at the positions described
in Fig. 3.4.12. The results of the measurements
are summarized in Table 3.4.4. It may be noted
that an axial shift occurred that was significant
in magnitude but remarkably small for the amount
of welding involved. These results indicate that
some distortion is inevitable and must be either
accepted or removed by subsequent machining and
that a stress relief anneal will be necessary to
remove effects of residual stresses during oper-
ation.
TABLE 3.4.4. RESULTS OF MICROMETER
MEASUREMENTSONAXISOF PUMPBARREL
Dimensions (in.)
It may be noted that the shell flange is quite Posit ion Before After
large, the intent being to minimize distortion of Welding Welding
Change
the flange and thereby require a realistic proportion
of the distortion during welding to occur A1 2.459 2.447 -0.01 2
in the barrel sleeve and hence in the barrel itself.
The restraint provided by the auxiliary weldment
2
3
2.459
2.444
2.468
2.468
+0.009
+ 0.024
shown in Fig. 3.4.8 was intended to supplement 4 2.437 2.431 -0.006
the afore-mentioned condition and, hence, to more
nearly simulate the northhead pressure shell.
B1
2
2.492
2.466
2.480
2.470
-0.012
+ 0.004
2.433 +0.017
s welded into the p 2.429 -0.008
welding procedure
2.516 -0.008
determined by micrometer me
2.474
2.394
2.431
+0.001
+ 0.01 4
-0.006
2.56T -0.002
2.573 -0.002
2.361 +0.010
2.437 -0.003
2.594 0
summarized In Table
d that the maximum changes
considering the extent of
2.478
2.321
2.438
-0.006
+0.003
- 0.004
181