Stick welder

1. The process of creating welding joint is caused by fusion on joining materials, thus leading to melting of the base metal or other material. In addition, filler materials are typically added to the joint. They form a pool of molten material that creates a joint after cooling. As a rule, a base material is not as strong as a joint. The pressure also can be applied during the welding process. One can connect parts together in many ways. The most usual are fastening by bolts or rivets, brazing and welding. If you want to do the continuous joint on long parts of joining surfaces you need welding. This is the main advantage of welding, especially for enclosed cans such as boilers, etc. Carbon and low-alloy steels are the most frequently used materials in welded constructions. The weldability of steels varies depending on a carbon content and total alloying content. Aluminium alloys are also generally weldable. Copper and its alloys are also weldable, but the high thermal conductivity makes welding difficult. As a rule, you can easily weld plastic or glass. They usually welded by heating to melting range and by simply pressing surfaces together. Rust, oxidation, grease, and dirt prevent a proper weld joint. Hot metal requires protection and all weld processes use one of two protection methods: flux or shielding gas. The form of a welding flux (used in stick welder) is usually liquid, paste or solid. It creates a small pocket of gas while evaporating. This is how the oxidation process prevented. But solid flux must be removed after completing the welding. To protect welding shielding gas surrounds point of welding. The original fusion technique is known from the earliest uses of iron. People heated small pieces of iron to welding temperature and then hammered or pressed them to create larger useful pieces. The most common today’s welding techniques are arc welding, oxyacetylene welding, resistance, electron-beam, friction, laser welding and other. The largest total volume of welding is shielded metal-arc welding. An electric arc is created between materials leading to electrode’s metal melting and transferring it to the joint in this process. Another technique is gas (usually oxyacetylene) welding. For fusion process heat is supplied by burned acetylene in oxygen. The resistance welding is a process when the required heat is generated from electrical resistance of the joint. Such welds are made using low-voltage and high current power source with pressure applied. Electron-beam welding is based on a dense stream of high-velocity electrons bombarding the joint. The friction welding is based on heating joining parts by friction. Laser welding is accomplished when materials are fused together by heat generated from a laser source. The quality of weld depends on the base material, filler and flux material, energy and design. The strength of material and weld depends on the welding method and concentration of energy input, type of the flux and filler, and weldability of the base material. The weld quality also much depends on the heat-affected zone. To test the quality of the weld either destructive or nondestructive methods are used. Possible defects of welds are cracks, gas, and non-metallic inclusions, distortions, incomplete penetration, lack of fusion and lamellar tearing.