Welder

There are different ways to connect the parts together. Usually this can be done by fasten them with rivets or bolts, solder or weld them together. If you want to do the solid 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.

Welding parts can be geometrically prepared in different ways. V-butt joint, lap joint butt joint, and T-joint are the basic types of weld joints. There are many other types of joints existing. Many welding processes require the particular joint design. Resistance, laser, and electron-beam welding are most frequently performed on the lap joints.

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.

The original fusion technique is known from the earliest uses of iron. The process of joining small pieces of iron to larger ones was through heating to welding temperature and hammering or pressing together. The most common today’s welding techniques are arc welding, oxyacetylene welding, resistance, electron-beam, friction, laser welding and other. The shielded metal-arc welding is the most used technique. An electric arc is created between materials leading to electrode’s metal melting and transferring it to the joint in this process. Oxyacetylene (or gas) welding is another common technique. The source of heat in this process is acetylene burned in the atmosphere of 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 process of creating welding joint is caused by fusion on joining materials, thus leading to melting of the base metal or other material. Usually, there are fillers that added to joining base materials. The joint is created in the process of cooling the pool of those molten materials. As a rule, a base material is not as strong as a joint. The pressure also can be applied during the welding process.

The quality of weld depends on the base material, filler and flux material, energy and design. The welding method and concentration of energy input, weldability of the base material and type of the filler and flux influence the strength of weld and material. The weld quality also much depends on the heat-affected zone. Usually, one of the destructive or nondestructive methods is used to test the quality of the weld. Possible defects of welds are cracks, gas, and non-metallic inclusions, distortions, incomplete penetration, lack of fusion and lamellar tearing.