Can I teach myself welding?

The metalworking industry has instituted codes and specifications to guide welders, weld inspectors, engineers, managers, and property owners in proper welding technique, design of welds, how to judge the quality of welding procedure specification, how to judge the skill of the person performing the weld, and how to ensure the quality of a welding job. Methods such as visual inspection, radiography, ultrasonic testing, phased-array ultrasonics, dye penetrant inspection, magnetic particle inspection, or industrial computed tomography can help with detection and analysis of certain defects. Where Q = heat input welding speed (mm/min). The efficiency is dependent on the welding process used, with shielded metal arc welding having a value of 0.75, gas metal arc welding and submerged arc welding, 0.9, and gas tungsten arc welding, 0.8. Methods of alleviating the stresses and brittleness created in the HAZ include stress relieving and tempering.

Crystalline solids have cohesion because of a metallic, or chemical bond formed between the constituent atoms. Two types of chemical bonds are possible: covalent and the ionic. To form an Ionic Bond, either a bonding electron (valence) or a bonding electron (valence) must separate from one atom. Then the electron attaches to another atom to form ionic bonds. If the ions have an equilibrium position and there is no force between them, this is called bonding in the stat position. If the ions are under tension, their inter-ionic spacing is increased, which creates an electrostatic attractive force. The dominant force between the atomic nuclear nuclei is a repulsing and compressive force.

World War I caused a major surge in the use of welding, with the various military powers attempting to determine which of the several new welding processes would be best. The British primarily used arc welding, even constructing a ship, the "Fullagar" with an entirely welded hull. Arc welding was first applied to aircraft during the war as well, as some German airplane fuselages were constructed using the process. Also noteworthy is the first welded road bridge in the world, the Maurzyce Bridge in Poland (1928). During the 1920s, significant advances were made in welding technology, including the introduction of automatic welding in 1920, in which electrode wire was fed continuously. Shielding gas became a subject receiving much attention, as scientists attempted to protect welds from the effects of oxygen and nitrogen in the atmosphere. Porosity and brittleness were the primary problems, and the solutions that developed included the use of hydrogen, argon, and helium as welding atmospheres. During the following decade, further advances allowed for the welding of reactive metals like aluminum and magnesium. This in conjunction with developments in automatic welding, alternating current, and fluxes fed a major expansion of arc welding during the 1930s and then during World War II. In 1930, the first all-welded merchant vessel, M/S Carolinian, was launched.

The new energy beam welding processes, laser beam welding and electron beam weld, have been very popular in high-production applications. Both processes are very similar, with the main difference being their power source. While laser beam welding uses a focused laser beam, electron beam welding uses an electron beam in a vacuum. Both have high energy densities, which allows for deep penetration and minimizes the area of weld. Both are very fast and can be automated easily, making them extremely productive. Their primary drawbacks include their high equipment costs, which are declining, and the susceptibility for thermal cracking. Laser-hybrid welding is a new development in this area. It uses principles from both laser beam and arc welding to produce better weld properties.

There are many power supplies that can be used to supply the electricity required for arc welding processes. Constant current power supplies (or constant voltage power supplies) are the most popular welding power supplies. The length of an arc in arc welding is directly proportional to its voltage. However, the current determines the heat input. Because they can maintain a constant current, even when the voltage changes, constant current power supplies are used most frequently for manual welding processes like gas tungsten or shielded metal welding. Because manual welding can be challenging, it is possible to not hold the electrode steady. As a result, the voltage and arc lengths will fluctuate. These power supplies are used to automate welding processes like gas metal arc welding and flux-cored. Because of the large current changes, any fluctuations in the distance between wire and base material are quickly corrected by an increase in current, the arc length is maintained constant. If the wire and base material are too close together, the current will quickly increase. This causes heat to increase, and the tip of wire to melt.