propagated up into the pipe wall. While this system very lil<ely is satisfactory 

 for cyclical service at some pressure less than 3,000 psi, it was not tested at 

 lower pressures and its maximum useful depth rating is not known. 



5. Composite gaskets were made by cementing 1/8-inch-thick steel 

 washers to 1/8-inch-thick lead washers with epoxy cement (see Figure 24). 

 The composite gaskets were then treated and assembled to the glass pipe 

 end closures in the same manner as described above for the copper— steel 

 gaskets. 



While the lead bearing system provided the most "compliant" of 

 the glass-to-metal bearing systems (see Figure 25), it did not produce the 

 desired critical pressure for the system. All specimens tested failed during 

 the first cycle to 3,000 psi. While this system very likely is satisfactory for 

 cyclical service at some pressure less than 3,000 psi, it was not tested at 

 lower pressure, and its maximum useful depth range is not known. 



6. The gaskets in this test assembly consisted of 1/4-inch-thick 

 washers machined from 6061-T6 aluminum and finished to a 32-rms sur- 

 face finish. A 0.0025-inch-thick molybdenum disulfide coating was then 

 applied to one side of each washer. Figure 26 shows the component parts 

 of the specimen assembly. In the final assembly, the bare sides of the 

 aluminum washers were sealed to the glass pipe end flanges with RTV 

 silicone rubber and the molybdenum-disulfide-coated sides were placed 



in contact with the steel end-closure discs. The assembly was compressed 



by tightening the tie bolts, and the 

 flange section of joints between the washers and steel 



4-inch-iD X 6-inch-iong end platcs wcre then sealed with RTV 



Pyrex glass pipe 



silicone rubber (Figure 27). 



Figure 28 shows the aluminum 

 bearing ring after 1 cycles to 3,000 psi 

 followed by 10 cycles to 4,000 psi. The 

 resulting indentation is very difficult to 

 detect. One specimen assembly survived 

 two 10-cycle tests successively to 3,000 

 and 4,000 psi. A second specimen 

 failed after one cycle to 3,000 psi and 

 a third specimen survived three 10- 

 cycle tests successively to 3,000, 

 4,000, and 5,000 psi and six cycles 

 to 6,000 psi. 



surface lapped 



to remove 



irregularities 



1/8-inch-thick lead 

 (epoxy used to join 

 washers) 



1/8-inch-thick 

 mild steel 



stainless steel 

 type 316 



Figure 24. Experimental sealing and 

 bearing system utilizing a 

 composite lead— steel washer 

 between the glass pipe end 

 flange and the metal end- 

 closure plate. 



25 



