Methods of Joining Metals

1. Soldering:

Soldering is a method of joining metal surfaces together by means of a low melting pointThe temperature at which a solid changes its state to liquid at atmospheric pressure is called the melting point of that liquid. The melting point is usually defined as the point... More metal alloy called solder (flexible lead wire). The solder is melted and applied to the metal parts to be joined and this forms a good bond. The metals to be joined will have a higher melting point than the solder.

Types of Soldering:

There are two types of soldering:

a. Soft Soldering: This type of soldering takes place in temperatures between 90°C – 450°C. The soft solder used during this soldering operation is an alloy of tin and lead and it is used to join metals where strength is not an important factor, for example, joining wires in radios and televisions.

b. Hard (Silver) Soldering: Silver soldering makes use of solder which melts at or above red heat (or alloys with melting points above 450 °C). This is used on metal parts that need to be exposed to greater heat than the melting point of soft solder, for example, joining metals like silver and copper.

The solders used alloys of silver, copper and zinc which have higher melting points and provide stronger bonds. It is used in refrigeration and air-conditioning systems.

red-heat” is observed somewhere between 500-1000°C

Tools and Materials Required for Soldering:

The tools and materials used during soldering operations are grouped together. They include the following: