276
Gas Tungsten Arc Welding Handbook
parts are sprayed with a salt mixture and allowed to
corrode, simulating years of exposure to the weather.
Such tests are usually required by the specifi cation
used by the fabricator. Weld test parameters made on
the qualifi cation test weldments must be duplicated
on the production part without deviation to maintain
the proper corrosion resistance.
Ferrite Test
A ferrite test on completed stainless steel welds
determines the amount of magnetic ferrite in an
austenitic (nonmagnetic) weld. Insuffi cient ferrite in a
weld made under high restraint is prone to cracking at
red heat. Limits of ferrite will depend on the use of the
fi nal weldment. These amounts are usually specifi ed
in the fabrication specifi cation.
Weld test parameters and fi ller metals used on
qualifi cation test weldments must be duplicated on
the production part without deviation to maintain the
proper ferrite content.
Weld Repair
If a weldment fails inspection, the welding
inspector will review it in order to determine the
extent of damage that may be caused by repairing the
weld and whether the weldment can fulfi ll its func-
tion if the defect is allowed to remain in place. If the
function of the weldment is affected by the defect, the
weldment must be discarded and replaced. In some
cases, the defect may not affect the functionality of the
weldment, in which case it can be left. These determi-
nations are made on a case-by-case basis.
If a part requires rework, a thorough welding
procedure should be established to minimize the
effect of the repair on the remaining portion of the
weld. This procedure must consider the procedure
used to create the original weld. It must also consider
the following:
• the condition of the base metal and weld
• the type of fi ller metal to be used in the
repair
• the welding sequence
• any in-process inspection required during
the repair
• tooling required for the repair
• the fi nal weld’s mechanical properties
Incomplete consideration of any of these factors
may result in further rejection of the weld repair and
possible failure of the weld when placed into service.
Dimensional Repairs
Dimensional repairs are repairs that are required
because the weld is too small for the material and joint
type. These repairs involve the addition of material
to increase weld size and are usually necessary due
to the insuffi cient addition of fi ller metal during the
welding operation. Conditions that require dimen-
sional repairs are as follows:
Figure 18-21. Round-type tensile bars are shown in the
foreground of this image. (Photo courtesy of Tinius Olsen)
Figure 18-22. A fl at tensile test bar is being tested. (Photo
courtesy of Tinius Olsen)