are more readily weldable out of position,
particularly vertical-up and vertical-down.
These wires operate with a mixed
shielding gas (argon and CO2) rather
than straight CO2, which provides a sta-
ble arc similar to, but not as steady as,
that of a T-1 flux-cored wire. As a result,
these wires often are easier to train weld-
ing operators to use, but they still pro-
vide the toughness desired with a tradi-
tional T- 5 wire. Usually they have impact
properties of more than 37 joules at -58
degrees F in the as-welded condition. In
the PWHT condition, they can offer
toughness greater than 47 joules at - 40
degrees F. These newer T- 5 wires typically have greater slag coverage as well. The
slag provides good-quality welds, yet is
relatively easy to remove.
One disadvantage of these newer
wires, however, is that unlike other T- 5
wires, they operate on DC, negative
polarity (DCEN) and therefore require a
different power source. Also, the weld
puddle on these wires types tends to
behave differently than other T-1 or T- 5
wires, which may require additional
welder training to use them properly.
THE X-FACTOR
With these newer wires, as well as the
traditional T- 5 flux-cored wires and T-1
wires, the X-factor is critical. The X-factor is a formula that measures a weldment’s resistance to temper embrittlement,
which is the brittleness, or loss of toughness, that occurs when the weldment
is held (or slowly cooled) through a
temperature range of approximately 850
to 1,100 degrees F. It is particularly
important when welding chrome-moly.
For all types of flux-cored wire welding
of chrome-moly, the X-factor should
be below 15.
MAKING THE CHOICE
Determining whether an application can
benefit from a T-1 or T- 5 welding
wire depends on several factors, including
whether the specifications for the
particular chrome-moly application can
be changed. In some circumstances, it
may simply not be an option to change
from stick or submerged arc welding.
In others, switching might not improve
the weld. However, the latest T-1 or T- 5
flux-cored wires are worth a look
because, in some cases, they may improve
productivity and help companies gain
a competitive edge.
Enter reader service code 197234 at www.ffid.net
Joe Bundy is a research and design
engineering manager for the Tubular Wire
Division of Hobart Brothers, 101 Trade
Square E., Troy, OH 45373, 937-332-
4000, www.hobartbrothers.com.
