Carbon-arc welding

From GAWDAwiki

Carbon-arc welding is a welding process in which heat is produced by an arc between a carbon electrode and a work piece. The work piece is heated and melted by the arc and a joint is formed. Shielding is typically not employed. Filler metal may be used. Nowadays, TIG welding is used in place of carbon-arc welding in many applications.^[1]

Advantages

• Low cost
• Quick learning curve
• Easily automated
• Minimal distortion of work pieces

Disadvantages

• Porosity of weld^[2]

Types of Carbon-arc Welding

1. Twin Carbon Electrode Arc Welding: This is a variation of carbon arc welding in which an arc is established when two carbon electrodes are brought together. The arc forms in front of the apex angle formed by the electrodes and fans out to create a soft heat or arc flame—softer than a single carbon arc. Shielding and pressure are not used. Pressure and filler metals are sometimes used. Twin carbon electrode arc welding is sometimes used for brazing.
2. Gas Carbon-arc Welding: In this variation of carbon arc welding, shielding gases (inert or gas mixtures) are used. Pressure and filler metals are sometimes used.
3. Shielded Carbon-arc Welding: This method also involves an arc between a carbon electrode and a work piece. However, in this scenario shielding is provided by the combustion of a solid material fed into the arc, from a blanket of flux on the arc or from both. Pressure and filler metals are sometimes used.¹

References

1. http://www.fortunecity.com/village/lind/247/weld_book/Ch6.htm
2. http://www.substech.com/dokuwiki/doku.php?id=carbon_arc_welding