Page 95 - CITS - Welder - Trade Theory

WELDER - CITS

Silver-copper-zinc An ideal composition for economy in brazing operation Flux necessary
cadmium (43 percent requiring a low temperature, quick and complete penetration.
silver) - Type BA-Cu- Suitable on steel, copper, brass, bronze, copper-nickel alloys
Ag 16A and nickel-silver. (Flame neutral)
Silver-copper-zinc- This alloy is also suitable for steel, copper-nickel alloys and Flux necessary
cadmium (50 percent nickel-silvers. (Flame neutral)
silver) - Type BA-Cu-
Ag 11
Silver-copper-zinc- Specially suitable for brazing tungsten carbide tips to rock Flux necessary
cadmium nickel (50 drills, milling cutters, cutting and shaping tools; also suitable
percent silver) for brazing steels which are difficult to ‘wet’ such as stainless
-Type BA-Cu-Ag 12 steels. (Flame neutral)

Gas welding fluxes and function

Objectives : At the end of this lesson you shall be able to
• explain flux and its function in gas welding
• describe the types of welding fluxes and their storage.

Flux is a fusible (easily melted) chemical compound to be applied before and during welding to prevent unwanted
chemical action during welding and thus making the welding operation easier.
The function of flux in gas welding: To dissolve oxides and to prevent impurities and other inclusion that could
affect the weld quality.
Fluxes help the flow of their metal into very small gap between the metals being joined.
Fluxes act as cleaning agents to dissolve and remove oxides and clean the metal for welding from dirt and other
impurities.
Fluxes are available in the form of paste, powder and liquid.
The method of application of flux is shown in Fig 1.
Storing of fluxes: Where the flux is in the form of a coating on the filler rod, protect carefully at all times against
damage and dampness. (Fig 2)
Seal flux tin lids when storing especially for long periods.
Though the inner envelope of an oxy-acetylene flame offers protection to the weld metal, it is necessary to use
a flux in most cases. Flux used during welding not only protects the weldment from oxidation but also from a
slag which floats up and allows clean weld metal, to be deposited. After the completion of welding, flux residues
should be cleaned.

Fig 1

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CITS : C G & M - Welder - Lesson 14-26 CITS : C G & M - Welder - Lesson 14-26