Clarke 6012200, Инструкция по эксплуатации и обслуживанию

Страница: 14 / 28

2. TIG WELDING
TIG welding Is primarily a DC current process, but can also utilise AC, usually for
very thin materials and when welding Aluminium or other non ferrous metals.
(This range does not utilise AC current)
It uses a non-consumable tungsten (or tungsten alloy) electrode, held in a torch.
Shielding gas (100% Argon), is fed through the torch to protect
a. the electrode,
b. molten weld pool,
and c. solidifying weld metal........ from contamination by the atmosphere.
The electric arc is produced by the passage of current through the conductive,
ionized shielding gas. The arc is established between the tip of the electrode and
the work. Heat generated by the arc melts the base metal. Once the arc and
weld pool are established, the torch is moved along the joint and the arc
progressively melts the joined surfaces. Filler wire, if used, is usually added to the
leading edge of the weld pool to fill the joint.
This process is ideally suited for welding thin metals, pressure vessels, heat
exchangers, pipes etc., where accuracy and a high quality weld is desired, as it
produces a very low porosity weld.
TIG Welding Process Advantages
• It produces superior quality welds, generally free of defects.
• It is free of the spatter which occurs with other arc welding processes.
• It can be used with or without filler metal as required for the specific
application.
• It allows excellent control of root pass weld penetration.
• It can produce inexpensive autogenous welds at high speeds.
• It can use relatively inexpensive power supplies.
• It allows precise control of the welding variables.
• Welds all metals, if AC current is utilised.
• Capable of welding very thin material (0.5mm), without undue distortion.
Main Features of TIG Welding
1. Welds all metals, if AC current is utilised.
2. Electronic control of welding current.
3. Forced air cooling.
4. A Thermal Overload Protection Device prevents overheating the transformer.
Limitations
1. Greater weld dexterity is required
2. It is more expensive to weld thicker materials - greater than 4 - 5mm
14