Program investigates the effects of varied welding positions on weld qualities. Progressive changes in bead geometry occur as the weld plane angle is varied from upslope to downslope. The gravitational effect on the weld puddle varies greatly with welding position

Haryung, J.

Wroth, R. S.

English

NASA Technical Reports Server

Direction 
Of Torch 
Travel 
Pore Escape Paths 
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Ill 
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Torch Axis 
Weld Puddle 
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Metal
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Weld Metal 
June 1967	 Brief 67-10177 
NASA TECH BRIEF	 1 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Effect of Welding Position on Porosity Formation in Aluminum Alloy Welds 
A program has been initiated to investigate the ef-
fects of varied welding positions on such weld qualities 
as deposit soundness and uniformity, bead geometry, 
chemical composition, and mechanical properties. 
Automatic MIG welds have been prepared in positions 
ranging from flat (0 degrees) to 35 degrees both up-
slope and downslope, using standing welding proce-
dures as weld speed in inches per minute, weld current 
and voltage, torch lead angle, and shielding gas de-
livery rates. 
Progressive changes in bead geometry occur as the 
weld plane angle is varied from 350 upslope to 350 
downslope. Generally, upslope welds are characterized
by a narrow weld deposit with a high crown, while 
downslope welds are wide and flat. The fused cross 
section area is found to be greater and to contain 
somewhat greater amounts of copper (from welding 
2014-T6 aluminum alloy) in downslope welding, 
indicating that more of the parent plate is melted when 
welding in this plane. Nondestructive inspection indi-
cates that fewer surface and internal defects are pro-
duced by welding upslope as opposed to downslope. 
Upslope welds made at 25° and 35° angles are com-
pletely free of defects. As the weld plane angle is 
reduced through the flat position to a 350 downslope 
angle, both surface and internal porosity become 
(continued ovkal) 
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=19670000177 2020-03-11T20:51:28+00:00Z
Brief 67-10177 
progressively more severe. The porosity content ob- 2.	 Inquiries concerning this innovation may be di-
served in all downslope welds are such that these will rected to: 
not meet , acceptance specifications. Technology Utilization Officer 
As shown in the figure, the gravitational effect on Marshall Space Flight Center 
the weld puddle varies greatly with welding position. Huntsville, Alabama 35812 
Porosity forming in the weld puddle, rises vertically Reference: B67-10177 
toward the surface where it is liberated in the form 
of gas. In the case of upslope welds, the escape path 
is quite short and essentially all porosity is liberated Pateflt status:. 
before the puddle solidifies. Downslope welds, how- No patent action is contemplated by NASA. 
ever, present a much longer escape path and the , weld Source: Robert S. Wroth and John Haiyung puddle has a tendency to solidify before the gas bub-
of Douglas Aircraft Company bles can rise to the surface and they are entrapped
under contract to in the weld deposit as porosity. Marshall Space Flight Center 
Notes: 
1.	 This method does not eliminate or minimize the 
formation of gas bubbles in the weld puddle but ''	 (MFS23 18) 
does facilitate their escape.


Effect of welding position on porosity formation in aluminum alloy welds

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