WELDING
CHROME-MOLY
STEEL
Are tubular wires an option?
By Joe Bundy
COMPANIES traditionally have relied on shielded metal
arc welding (SMAW, or stick) electrodes for welding
chrome-moly tube and pipe, in part for the mechanical and
chemical properties they provide and in part because they
are the accepted standard specified for such applications.
However, with greater demands to increase productivity and
stay competitive, some companies are considering a wire welding process as a means to get ahead. Some have begun to use
T-1 or T- 5 gas-shielded, flux-cored wires, both of which have
undergone significant advancements in recent years and offer
greater consistency than similar products offered in the past.
Like any filler metal, flux-cored wires for chrome-moly
have distinct advantages and disadvantages. Flux-cored wire’s
main advantage is speed. Because it comes on a spool and is
hundreds of feet long, it can provide a long, continuous weld,
which is much faster than stopping to get a new stick after 12
or 15 inches of welding. However, flux-cored wire isn’t the
best consumable for every welding job. Learning about the
main types of flux-cored wire for chrome-moly tube and pipe
is the first step in considering the switch.
WHAT YOU SHOULD
KNOW ABOUT T-1 WIRES
Flux-cored wires referred to as T-1 have a rutile (or acidic) slag
system. Suppliers often offer T-1 wires in several product classes to match the chemical and mechanical properties of various
chrome-moly tube and pipe. These wire classes include B2, B3,
B6, B8, and B9, which contain from 1.25 to 10. 5 percent
chrome and 0.5 to 1 percent molybdenum (see Figure 1).
A T-1 wire’s slag system results in an easy-to-remove slag
and makes the wire well-suited for welding on multipass
applications because it requires minimal cleanup between
passes. This category of wire also creates low amounts of
spatter, which reduces the need for postweld cleaning.
Typically, T-1 flux-cored wires for chrome-moly have a
stable arc and weld smoothly. Consequently, they appeal to
