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ANP PROJECT PROGRESS REPORT
COMPOSITE TUBING
H. lnouye M. R. D'Amorel
*
The fabrication of composite tubing by coextrusion
was described previou~ly.~~6 Initially
these studies were made in order to develop
~ ~ billets which, when extruded, would result in
composite tubing with predetermined thicknesses
of the various metal layers. To date, billet
configurations for the fabrication of two- and
three-ply tube blanks have been developed.
An extrusion billet design used for the fabri-
cation of two-ply tube blanks of equal layer
thicknesses is shown in Fig. 3.3.5. The effect
of various alloy combinations on the layer thick-
nesses after extrusion was of particular interest,
since it is known that the thickness of metals with
higher resistance to plastic deformation will be
greater after hot rolling than was calculated.
Billets of the configuration shown in Fig. 3.3.5
were extruded at 2100°F to l\-in.-OD, k-in.-woll
tube blanks. Tube blanks of several combinations
of alloys were sectioned longitudinally and the
layer thicknesses determined. The results, as
presented in Table 3.3.8, show that variations in
the layer thicknesses are independent of the
40n assignment from Pratt & Whitney Aircraft.
'J. H. Coobs et aL, ANP Quar. Prog. Rep. Sept. 10,
1955, ORNL-1947, p 145.
6T. K. Roche and H. Inouye, ANP Quai. Prog. Rep.
Dec. 10, 1955, ORNL-2012, p 155.
NOSE AND INSlM CYLINDER OF TYPE 316
STAINLESS STEEL
UNCLASSIFIED
WNL-LR-DVG 42903
ORILL %-in HOLE % ir DEEP
NOTE: ALL DIMENSIONS
ARE IN INCHES
Fig. 3.3.5. Extrusion Billet Design for the Pro-
duction of Tube Blanks with Equal Layer Thick-
nesses.
168
TABLE 3.3.8. LAYER THICKNESSES OF ti2
COMPOSITE TUBE BLANKS
Alloy
Combination
Incbnel-type 316 stainless steel
ThiFkness (in.)
Outer Inner
Layer Layer*
Front 0.122 0.130
Middle 0.130 0,122
End 0.106 0.122
Average 0.119 0.125
Hastelloy 8-type 316 stainless steel
Front 0.110 0,142
Middle 0.114 0.134
End 0,110 0.122
Averoge 0,111 0.133
Monel-type 316 stainless steel
Front 0.126 0.130
Middle 0.118 0.134
End 0.138 0.134
Average 0.127 0.132
Nickel-type 316 stainless steel
Front
Middle 0,138 0.098
End 0,122 0.126
Average 0,130 0,112
*Inner layer was type 316 stainless steel in all the
blanks.
combination of alloys, although the resistances
of the alloys to plastic deformation may vary
greatly. Accurate thickness measurements were
difficult to obtain because of the roughness of the
extruded blank.
Tube blanks of the combinations listed were re-
drawn to 0.187-in.-OD, 0.020-in.-wall tubing with
fair success. As a result of inexperience in proc-
essing duplex tubing, however, a few longitudinal
cracks were present in the lnconel layer of the
Inconel-type 316 stainless steel combination. Al-
so, the Hastelloy B-type 316 stainless steel com-
bination was rejected during processing because
of longitudinal splitting. Preliminary examinations
of the small-diameter tubing obtained showed that
thermal bonds were maintained at the metal inter-
faces throughout the processing and that the layer _-
thicknesses were about equal.
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