is helpful for small jobs and can keep costs down.
Still, fabricators need to consider SMAW’s stub loss
and slag removal to determine if the process’s low
electrode costs still make it cost-e;ective overall.
A 309 or 312 SMAW electrode is a good choice for
stick welding stainless steel, especially for maintenance or repair applications. It o;ers high cracking
resistance and good strength, and typically can join
stainless steel already in service, even if the specific
material grade isn’t known.
Gas Metal Arc and
Flux-cored Arc Welding
When productivity is a priority for stainless steel
welding, wire feed processes o;er e;iciency and
good bead appearance. Advancements in equipment and filler metal have made these processes
easier to use, even for those newer to welding stainless steel.
Many fabricators perform gas metal arc welding
(GMAW) of stainless steel with a solid wire. GMAW
has moderate equipment complexity and operator
skill requirements, and for stainless steel welding, it
can be used in pulse or spray transfer mode.
The cost per pound for solid wire is less than other
choices, but the shielding gas is an added expense.
Using an argon-based shielding gas blend—such as
98 percent argon/2 percent CO2, or an argon/helium
mixture—helps reduce spatter.
Flux-cored arc welding (FCAW) can be more productive than GMAW but does generate slag and
spatter, which adds time and cost for cleanup. FCAW
also has the highest cost per pound for stainless filler metals, as the flux’s alloying elements are more
expensive to manufacture.
However, many FCAW wires run on common
shielding gas mixtures such as argon/CO2 or 100
percent CO2. A fabricator new to welding stainless
steel would probably not need to invest in a di;erent type of gas or delivery system.
Metal-cored arc welding, either with pulsed or
standard spray methods, provides fast travel speeds
that input less heat into the weld. This helps prevent
warping and distortion when welding stainless steel.
Although metal-cored welding produces less
spatter than other forms of wire welding, the price
per pound for the stainless steel filler metal is the
highest. When deciding on this filler metal and process, fabricators should weigh the upfront cost versus the productivity gains and the potential reduction in rework and cleanup.
Submerged Arc Welding
Many fabricators have submerged arc welding
(SAW) systems in place for welding carbon steel,
but SAW also o;ers significant benefits for stainless
steel, including greater productivity and extremely
low spatter levels, which help save time and money
on cleanup. SAW is well-suited for thick materials
and large applications such as storage or liquid natural gas tanks. Though it’s limited to the flat welding
position, it can be performed by less-skilled operators. When using SAW on stainless steel, fabricators
employ a neutral or nonalloying flux, which does
not add alloys that could alter the chemistry of the
Gas Tungsten Arc Welding
Gas tungsten arc welding (GTAW) produces very lit-
tle spatter, even compared to SA W. If welders are us-
ing filler rod or wire, GTAW has a moderate cost per
pound, but it also requires high skill and typically
the most complex equipment. While aesthetics and
bead appearance with GTAW are very high, the pro-
ductivity is the lowest compared to other choices.
GTAW on stainless steel typically uses 100 percent
argon shielding gas, o;en with a secondary tank of
argon on hand for a backpurge between passes.
Most operations that use GTAW for stainless steel
do so for aesthetic reasons, simply because the process produces such a clean, precise weld.
Selecting the Right Process
As the use of stainless steel continues to grow, more
companies will have to become familiar with welding
the material. Cost may be the key consideration for
some operations, while reducing downtime and
improving productivity may be the keys for others.
Each process and filler metal choice comes with
trade-o;s. While there is no such thing as the perfect welding process for stainless steel, keeping
some key considerations in mind when selecting
the process and filler metal can help ensure success
and cost savings.
Jonathan Will is product manager at Hobart,
Stainless steel continues to gain popularity in applications across the fabrication industry, thanks mainly to its
corrosion resistance, strength, and toughness.
Made in the USA