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November, 1925
Forging- Stamping - Heat Tieating
A d a p t a b i l i t y o f Electric A r c W e l d i n g
By A. G. BISSELL*
A R C welding as a method of fabricating structural
steel is not a new departure. For quite a fewyears
it has been used in steel ship construction
in the assembly of steel ladders, masts, skylights, funnels,
deck stanchions, tanks, etc. Barges and floating
targets have also been entirely assembled, and pipe
lines, gas holders, oil tanks, small bridges and buildings
completely constructed by electric arc welding.
One interesting application of arc welding in the
erection of a structural steel building was recentlymade
at Eola, 111., where the Chicago, Burlington &
Quincy Railroad erected a 60x40-ft. one-story mill
type building, using scrap steel. An exact duplicate
of this building was also constructed by the riveted
method. Data furnished by W. T. Krattsch, engineer
of buildings of the railroad company, shows the following
comparison in erection costs: Arc Welded Riveted
Preparation cost, including material and
$1,000.00
shop fabrication $381.71
339.50
Field erection cost 404.49
$786.20 $1,339.50
It will be noted that the saving in favor of the arc
welded building lies in the minimum of preparation
required—merely^ the cutting of the steel to required
length. No clip angles, gusset plates or butt straps
are necessary, while besides these, the riveted job involved
shop details and layout, punching, painting,
FIG. 1—This test failed to produce any evidence of weakness
in the welded joints.
reaming and shop fabrication. In the riveted structure
27,100 pounds of steel were used, while but 25,619
pounds were used in the welded structure—a reduction
of 5y per cent in favor of the welded type of
construction. The saving in steel and reduction in
total erection cost in this case resulted in a final saying
of 41.3 per cent where arc welding was used in
place of riveting.
While there have been numerous applications of
arc welding in the fabrication of structural steel, test
•General Engineering Department, Westinghouse Electric
& Manufacturing Company.
409
data involving welded joints has not been complete.
Tests were therefore made of welded joints for tensile,
sheer, static, shock and fatigue strength of such
joints, compared to similar joints made by riveting,
and to the steel members welded together.
Using y2 in. and y in. plates beveled at 60 deg.
and arc welded to form a butt joint as a section subjected
to tensile strength tests, it was found that the
joint in the y> in. plate developed an average tensile
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FIG. 2—Method of welding the structural steel members
of a roof.
strength of 64,400 pounds per sq. in., with an elongation
of 4 per cent in a 1-inch section across the weld.
The steel in which the joint was made had a tensile
strength of between 65,000 and 70,000 pounds per sq.
in., and failure in the piece occurred in both base and
deposited metal. Welding wire used was hard-drawn
mill-steel, having a carbon content of .17 per cent and
a manganese content of .55 per cent.
In sheer test, a similar joint developed 50,550
pounds per sq. in. in sheer, and when subjected to
static tests, a pressure of 40 tons deformed the supporting
beams completely, but failed to produce any
evidence of failure in the welded joints. In fatigue
test, a riveted and welded joint of similar design were
mounted on a vibratory testing machine and subjected
to a vibration or vertical movement of 1/16 in. at the
rate of 1,760 complete cycles per minute. After 18
hours and 20 minutes, there was hardly a joint in the
riveted member which was not thoroughly loosened,
the rivets worn, the rivet holes enlarged, and a number
of portions broken off the main section. None of
the arc welded portions were weakened or damaged,
and it was necessary, in bringing about its destruction
in a continuance of the test, to append weights
to the outer ends of the riveted beams and arms. When
finally the model failed, failure occurred in the beams
and not in the welded joints. Under a sudden shock
of 700 tons administered directly to an arc welded
joint section, the welds did not fail, even though the
structural steel members of the section were severely
strained and deformed.
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