Soldering is a method for joining metallic materials with the aid of an alloy (solder), whose melting point is lower than the melting points of the materials to be joined. Unlike welding, the ends of the metal to be joined are not melted by soldering. A flux prevents oxidation of the surfaces and/or dissolves existing oxide films. A distinction is drawn between soft soldering and hard soldering (known also as brazing). A number of variations are possible for both forms of soldering: 

• soldering with a soldering iron or soldering torch
• furnace soldering
• dip soldering
• electric resistance soldering
• inductive soldering.

Nowadays soldering jobs on mechanical seals are performed almost exclusively with silver solders, the necessary soldering temperature being produced by inductive heating. By meticulously removing the residual flux and any scale, the soldered parts can display a practicable level of corrosion resistance.

Mechanical seal with brazed carbide seal faces