C02 welding

Egorov Aleksandr. Student of machine building department of TPU. Group 4V41.

The plan of presentation

The description of welding method;

Applications of CO2 welding;

Equipment for CO2 welding;

Materials for welding.

Welding - is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence.

Gas tungsten arc welding (GTAW)

Gas CO2 arc welding, also known as the active gas welding, is a manual arc welding process that uses a electrode wire to produce the weld. The weld area is protected from atmospheric contamination by a shielding gas (usually an active and inert gas such as argon).

Welding in CO2 is commonly used to weld various kinds sections and steels.

Advantages and Disadvantages

Advantages:

excellence of welded joints;

higher quality welds and a stable arc;

absence of necessity of application of flux or coating;

the high extent of density of the heat source;

the minimal interacting of metal of a weld with oxygen and nitrogen of air;

the opportunity of observation of the open arc and behind formation of a weld;

high efficiency, ample opportunities and ease of mechanization and automation;

at welding in inert gases stability of an arc increases and the loss of alloying elements;

welding in different positions.

Disadvantages:

necessity of application of protection from light and thermal radiation of an arc;

responsivity to an air flow;

necessity in additional difficult equipment; slower than most other welding techniques.

Operation of GTAW

Scheme of GTAW

At welding in a zone of an arc, through a welding head shielding gas is supplied continuously. Heat of an arc melts base metal and a filler rod. Molten metal of the weld pool, crystallizes and forms a weld. At welding by a tungstic electrode, the electrode is not melted. Formation of a weld occurs due to melting of base metal and filler metal.

Filler metal is added manually to the front end of the weld pool as it is needed.

At welding active metals often use a copper shoe to gain a good fusion of a weld and to ensure shield.

Applications of GTAW

GTAW can be used on nearly all weldable steels, though it is most often applied to mild steel and light metals es. It is often used when quality welds are extremely important, such as:

•in aerospace industry;

•aircraft and naval applications;

•bicycle industry;

•pipe welding in difficult positions;

•in maintenance and repair work cars;

•etc

Equipment for GTAW

Welding torch;

Welding power supply;

Wire electrode;

Shielding gas;

Welding machines and devices.

Welding torch

Welding power supply

Arc welding uses a constant current power source.

Used is better polarity when an electrode plus so as occurs maximum profusion.