16
Note:
When using self-shielding flux-core wire
it is very important to thoroughly chip and brush the
slag off each completed weld bead before making another pass or the next pass will be of poor quality.
Fillet Weld Joints.
Most fillet weld joints, on metals of moderate to heavy thickness, will require
multiple pass welds to produce strong joint. The illustrations in Figure 19 show the sequence of laying
multiple pass weld beads into a T fillet joint and a Lap fillet joint.
6.5 Spot welding
There are three methods of spot welding: Burn-Through, Punch and Fill, and the Lap Spot type. Each
method has advantages and disadvantages depending on the specific application as well as the
personal preference.
1.
The Burn Through method
welds two overlapped pieces of metal together by burning through
the top piece and into the bottom piece. When using the Burn-Through method, larger wire diameters
tends to work better than smaller diameters. Wire diameters that tends to work best, using the burn-
through method are 0.9 mm self-shielding flux-core wires. Do not use 0.75 mm self-shielding flux
core wires when using the burn-through method unless the metal is VERY thin or excessive filler metal
build-up and minimal penetration is acceptable. Always select the HIGH heat setting with the burn-
through method and tune in the wire speed prior to making any spot welds.
2.
The Punch and Fill method
produces a weld with the most finished appearance of the three
spot weld methods. In this method, a hole is punched or drilled into the top piece of metal and the
arc is directed through the hole to penetrate into the bottom piece. The puddle is allowed to fill up
the hole leaving a spot weld that is smooth and flushed with the weld surface established on the top
piece. Select the right wire diameter, heat setting, and tune in the wire speed as if you were welding
the same thickness material with a continuous bead.
3.
The Lap Spot method
directs the welding arc to penetrate both the bottom and the top piece at
the same time, right along each side of the lap joint seam. Select the right wire diameter, heat setting,
Lap Joint Welded
in Three Passes
„T“ Joint in
Three Passes
Punch and fill
Burn through
Lap spot
Summary of Contents for MIG 180-5
Page 20: ...22 C Lift the welding torch to the normal position to initiate the arc and start welding ...
Page 22: ...24 Spare parts listing ...
Page 49: ...51 Κατάλογος ανταλλακτικών ...
Page 74: ...76 Sklopni crtež rezervnih delova ...
Page 99: ...101 Sklopni crtež rezervnih delova ...
Page 127: ...129 Skica notranjosti naprave ...