Page 19 - HIWT Summer 2013 World of Welding

hiwt@welding.org HOBART INSTITUTE OF WELDING TECHNOLOGY

A STAINLESS STEEL WELDING APPLICATION

By Elmer Swank, Jr.
CWI/CWE
HIWT Instructor

QUESTION:

We are currently The 98% argon, 2% oxygen mixture is usually used to get
attaching twenty a spray transfer, with larger wire and on thicker material. A
stainless steel sheets spray transfer is usually limited to flat position. I have used
onto 1-1/2-inch x this gas mixture on the thickness you are welding, but you have
1-1/2-inch, one- to be careful not to use too much voltage and cause undercut
eighth-inch rolled (another place for cracks to start.)
stainless steel angle.
The radius of the You may want to try a tri-mix of 90% helium - 7½% argon
curve is 40 degrees. - 2½ % carbon dioxide for short-circuit transfer. Another
The sheets are welded good choice is a .045 gas shielded flux cored wire with carbon
to the angles using 1-inch stitch at 4 to 5-inch spacing. When dioxide or argon-carbon dioxide gas mixture. The performance
in place these sheets are subjected to upward water pressure of the small diameter flux cored wires have improved a lot in
and the curved sheet acts to direct flow. recent years.
A WP-280 HIWT Ad 3-25x4-875_Layout 1 12/21/11 9:28 AM Page 1
What we have found is cracking of the material around the
welds causing the sheets to push away from the angle
thus implying failure of the weld. Discussion has been on
going as to what causes this. We are using 98% argon and 2%
oxygen as a masking gas and .035 stainless steel wire. We
are considering going to 14 gauge material to help with the
problem.

What are you recommendations?

RESPONSE: Introducing the
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You didn’t say what type of stainless steel you are welding.
Many of the 400 series stainless steels will get brittle in the The water-cooled
heat affected zone, and may crack. Preheating to 300 or 400 solution for demanding
degrees will help to slow the cooling rate and minimize this applications
brittle condition. However, additional heat may cause more
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If the material is a 300 series stainless steel, it is less likely to • Multi-position handle
get brittle in the heat affected zone. From the description, it
sounds like the welds are too short and the spaces too long. • Improves operator
control and comfort
You may want to try 2-inch weld increments with a center-
to-center spacing of 4-inches before you increase material
thickness. Weldcraft.com

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