Chapter 29 Shielded Metal Arc Welding 807
Copyright Goodheart-Willcox Co., Inc.
The contour of the completed bead
can be slightly concave, dome-shaped,
or slightly convex. A bead with a convex
profi le has a little more material in the
joint but is better able to handle variable
stresses. In either case, the toes (edges) of
the bead should blend smoothly to the base
metal without causing a reduction in the
thickness of the material.
Fillet Weld Practice
Welding on 1 1/2″ × 4″ × 1/4″ to
1 1/2″ × 6″ × 1/4″ coupons is great practice
for learning to perform fi llet welds. The
following procedure can be used for fi llet
weld practice.
1. Obtain two 1 1/2″ × 4″ × 1/4″ steel coupons from your instructor or cut
them using the cutting torch. Grind the edge of one of the pieces straight
and smooth using a bench grinder or disc grinder.
Safety Note
When using a grinder, observe the power tool safety rules described in Chapter 8 and
these safety precautions:
• Wear OSHA-approved eye protection.
• Operate grinders and sanders in well-ventilated areas.
• Allow the tool to reach operating speed before contacting the work material.
• For disc grinders, apply only light pressure and let the tool do the work. Keep the tool
in constant motion.
• For bench grinders, apply even pressure and move the work material continuously
across the face of the stone/sander. Use the tool rest, and keep it adjusted to within
1/8″ from the grinding stone.
2. Using a scrap piece of steel, set the machine parameters according to
manufacturer’s specifi cations. Run a test bead, and then make any
adjustments to fi ne-tune the settings.
3. Strike the arc. Remember to call out the word cover before striking the
arc to alert anyone nearby to avoid looking at the arc without adequate
protection.
4. Tack weld the two coupons lengthwise and perpendicular to each other
by placing a small weld on each end of the joint. Tack welds are very
short, temporary beads used to hold parts in place while welding.
When the permanent weld is performed, the tack welds are remelted
and included in the fi nal bead. It may be necessary to realign the plates
after placing the fi rst tack due to contraction of the cooling tack weld.
Goodheart-Willcox Publisher
Figure 29-55. Welding in the 2F position.