The most widespread way of welding of metal is melting. At such way the metal parts put to each other end-to-end, leaving small gap. By means of special source of heat of edge of parts melt and connect.
Instruction
1. If warmed only parts, then on the place of joint of parts the seam which consists only of that metal of which parts are made is formed. If between parts have entered additional metal, then the connecting seam turns out from the parent and additional metal. The second option is most often used. Welding happens at temperature from 2000 degrees. Fusion welding is carried out in the arc, gas, electron beam and electroslag way. The most widespread – arc welding and gas welding.
2. Heat used at arc welding is made by electric discharge in gases. Temperature at such discharge reaches 30,000 degrees. To light arch use tension which arises in electrode and the most metal part. The electrode can participate in formation of seam (if as electrode the electrode wire), and maybe not melting (if electrode graphite, coal or tungsten is used).
3. As at such welding metal forms on joint surface with nitrogen and oxygen that can lead to connection strength reduction, the electrode is covered with special substances, and fill gumboil around electrode, melting, special substances and gumboil form gas veil which isolates connection from air. For the same purposes use gas stream which moves through special nozzle. These gases successfully isolate the melting metal.
4. For gas welding use the gases which are warmly burning down in oxygen, most often acetylene which gives temperature to 3200 degrees. It is possible to weld by means of acetylene burner metal parts up to 6 mm thick.