The main purpose of flux in soldering is to:

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ALP CBT 2 Electrician Previous Paper: Held on 22 Jan 2019 Shift 1

Answer 1

The main purpose of flux:

In high-temperature metal joining process like welding, soldering The primary function purpose of flux material is to prevent oxidation of base and filler material.
It also allows free flow of solder material on joints instead of forming beads.
It cleans the surface removing dirt and metal oxides also lowers the melting point of solder.

Important Points

Fluxes used in soldering:

There are two types of fluxes used in soldering
1. Corrosive type
2. Non-corrosive type
The common corrosive fluxes are Zinc chloride, mixtures of Zinc chloride and ammonium chloride
The flux must be washed off after soldering to prevent corrosion.
The non-corrosive fluxes are rosin and a mixture of rosin and alcohol.
These are essential for electrical connections where corrosion can create local high resistance and even loss of conduction.