Expandable metal plug is inserted to provide a seal to support the mold core with small blocks, referred to as chaplets, during the casting of a complex volute. Weld-warpage and multiple X ray inspection are eliminated by use of this technique

Goundrey, R. L.

Harris, C. L.

English

NASA Technical Reports Server

October 1966	 Brief 66-10489 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Plug Replaces Weld Filler as Seal in Complex Casting 
Plug	 Expansion Pin 
The problem: 
In casting a complex volute, it is necessary to sup-
port the mold core with small blocks, referred to as 
chaplets, during the casting process. These chaplets 
become an integral part of the housing but frequently 
fail to fuse completely with the poured metal and a 
leakage path results. It has been the practice to drill 
out the outer end of the chaplet and then backfill with 
weld metal. This is an expensive process and requires 
X-ray inspection to assure weld integrity. Warpage 
sometimes occurs during welding and subsequent heat 
treatments are required to restore the casting to design 
dimensions.
The solution: 
Instead of backfilling with weld material, the chap-
let is drilled out and an expandable metal plug is in-
serted to provide the seal. 
How it's done: 
The mold is supported in the normal manner with 
chaplets. Following pouring, the casting is heat 
treated to the desired condition. Then the end of each 
chaplet is drilled out so that a close fitting, expandable 
plug can be inserted.
(continued overlcafl 
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=19660000487 2020-03-11T17:38:05+00:00Z
Notes: 
1. Expandable plugs, capable of withstanding ex-
tremely high pressure are commercially available 
in a wide range of sizes. 
2. Weld-warpage and multiple X-ray inspection are 
eliminated by use of this technique. This new 
method can result in a cost saving of $500 per com-
ponent. 
3. Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
AEC/NASA Space Nuclear Propulsion 
Office 
U.S. Atomic Energy Commission 
Washington, D.C. 20545 
Reference: B66-10489
Patent status: 
No patent action is contemplated by NASA. 
Source: R. L. Goundrey and C. L. Harris 
of Aerojet-General Corporation 
under contract to 
Space Nuclear Propulsion Office 
(NU-0049) 
Brief 66-10489	 Category 05


Plug replaces weld filler as seal in complex casting

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