Weldability Of Typical Stud Bolt/Base Metal Combinations For Capacitor Discharge Welding. (Table 1); Welding - Cebora POWER SPOT 5700 Instruction Manual

7 WELDABILITY OF TYPICAL STUD BOLT/BASE METAL COMBINATIONS FOR CAPACITOR
DISCHARGE WELDING. (TABLE 1)
It is important to pay careful attention to the resistance and deformity at the welding point between the stud bolt and base
metal. In the case of steel, you must pay particular attention to brittleness. The material and resistance of the stud bolt have
limited tolerance; the carbon content in steel threaded stud bolts must be < 0.20%.
The surface of the base metal must be clean. Layers of paint, rust, waste, grease and non-weldable metal coatings
must be removed from the welding area. This must be done using appropriate means. Base metals with layers of
waste and rust must be cleaned thoroughly.
Stud material/Base metal
Steel up to 0.30 C %
Galvanized steel
Stainless steel 304/316
Al 99,5
Al Mg 3
Al Si 12
8

WELDING

This technology makes it possible to weld stud bolts on clean, but not oxidized, surfaces of mild steel, galvanized steel,
stainless steel, aluminum and brass. The rapidity of the process does not alter the surfaces on the side opposite from the
welding. Welding is not possible on case-hardened steel, oxidized or painted metal.
Before beginning production it is essential to carry out a few test welds to determine the proper setting of the power source
and gun (spring force), proceeding as follows:
• Insert the chosen stud bolt in the clamp X (previously adjusted as described in Fig. 2).
• Arrange the base sheet metal in conditions identical to those that will be used for the job in terms of thickness, earth
connection area, size of the workpiece, material quality.
• The terminals of the earth cable should be placed symmetrically, and as close as possible to the welding point.
• Activate the power source by means of the lighted switch E.
• Hold the gun and place the stud on the welding spot, avoiding to give blows, consequently damaging the striking tip of the
stud. Press the trigger O and, holding it pressed, push the gun evenly and not quickly. Once the right pressure is reached,
the weld will be automatically activated. If the surface of the material on which the stud bolt is to be welded is fl at, we
recommend mounting the three spacers Z after fi rst unscrewing the screws Y
• In this case it is recommended to push the gun until the three spacers are in touch with the piece and then press the trigger
to activate the welding.
These procedures are required to obtain the same pressure of the stud on the base material and consequently a
higher quality of the weld.
• The voltage and force values recommended on the display are intended as a starting point for calculating the
correct power source setting and for calibrating gun force.
• These values have been tested on samples of "base materials" (2 mm thick for steel and stainless steel and 1.2
mm thick for aluminium).
• Carry out a few welds, adjusting the voltage using the knob G, and the force of the gun using the setting knob Q, until the
welding is perfect.
• The gun should be removed keeping it perfectly aligned with the bolt, to avoid deforming the clamp (Fig4).
• Do not make welds to welded stud bolts.
24
Copper plated steel
up to 0.2 C%
A
B
A
-
-
-
High weldability: A Low weldability: B
NO NO
OK OK
Fig. 4
Stainless steel
Al Mg 3
304/316
A
B
A
-
-
-
Not weldable: -
Tab. 1
AI Si 12
- -
- -
- -
A B
B A
B A
Al 99,5
-
-
-
B
B
B
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