Brazing process attaches thermocouples to slot in type-347 stainless steel tube flush around its circumference. Electrolytic flashing with gold enhances brazing process. This installation procedure does not significantly change calibration of thermocouples used and does not cause major wear spots in the thin-walled devices

Curren, A. N.

Wycoff, K. C.

English

NASA Technical Reports Server

December 1970	 Brief 70-10655 
S	 NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Thermocouple Installation in Thin-Walled Tubes 
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.
Thin-Wall (0.012 in.) Tube Showing Two 0.010-in-Wide by 0.010-in-Deep Milled Instrument Slots. 
Commercially available thermocouple assemblies 
can now be installed in thin-walled devices without 
causing major weak spots in the walls. Tests were 
conducted with surface temperatures of up to 1095°F 
for several hours, including up to 100 on/off cycles, 
without failure. 
In the assembly described, a slot 0.010 in. wide 
by 0.010 in. deep was milled around the circumference 
Of a 347 stainless steel tube with a wall thickness of
0.012 in. Both this slot and the thermocouple assem-
blies to be used were then electrolytically flashed with 
0.0001 in. of gold to enhance the brazing process. 
Each thermocouple assembly was shaped and fitted 
so that its sensing tips were in the desired position in 
the slot and the entire assembly itself was inside 
the slot. The thermocouples were temporarily held in 
place by prick-punch upsets along the slot edges and 
were brazed to the slot with a brazing material com-
colitinucci ,, M-1i 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19700000635 2020-03-17T01:00:37+00:00Z
posed of 82% gold and 18% nickel by weight. Brazing 
was performed in a vacuum furnace at 1820°F. 
The completed assembly was a stainless steel thin 
walled tube with several thermocouples mounted 
flush around its circumference. The installation proce-
dure did not significantly change the calibration of the 
thermocouples used. 
Notes: 
This method can be applied to a variety of thin-
walled devices such as heaters, heat exchangers, and 
medical catheters.
2. No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B70-10655 
Patent status: 
No patent action is contemplated by NASA. 
Source: Arthur N. Curren and Kurt C. Wycoff 
Lewis Research Center 
(LEW-1 1222)
[II 
. 
Brief 70-10655	 Category 01


Thermocouple installation in thin-walled tubes

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