Welding involves the process of enjoining construction materials, such as metals and thermoplastics, through a process known as coalescence. Welders melt the workpieces and add filler material in order to form a weld pool of molten material. Welders will use a gas flame, electric arch, laser technology, electron beam, ultrasound technology, and friction-based tools to induce this fusion of materials. The industrial process may involve different environments, including open air, underwater, and outer space workstations. Welding can present danger to those unprotected due to a hazardous undertaking involving an array of burns, electrical shock, vision damage due to debris and shrapnel, poisonous gases and fumes, and overexposure to ultraviolet radiation.
The origins of welding can be traced back to the Bronze and Iron Age in Europe and the Middle East. In fact, Herodotus, author of the ���The Histories,� states that Glaucus of Chios was the man who invented iron welding. Other accounts describe early welders constructing the iron pillar in Delhi, India during 310 A.D. During the Middle Ages, blacksmiths pounded heated metal until bonding occurred, a process that would become known as forge welding. Nikolai Benardos created the first electric arch welding device that used carbon electrodes to promote the fusion between metals. Other welding methods, such as resistance welding and oxyfuel welding all enhanced primitive arc welding methods throughout the 19th century. The World Wars brought significant advancements to the welding industry due to major military demands for indestructible infrastructure. Some of these projects included: the Bridge of Maurzyce, the Fulagar, and German airplane fuselages. Modern advancements, such as plasma arch welding, electromagnetic pulse welding, and friction-stir welding have brought about high-quality applications among today's societal expanse across all industries.
There are four main types of welding used by laymen and professionals, including arc, gas, resistance, energy beam, and solid-state welding. Arc welding uses a welding power supply to create an electrical between the welding tools electrode and base material in order to fuse metals together. Gas welding employs oxyfuel in order to weld pipes and tubes. Resistance welding consists of heat generation by passing it through the contact of two or more metal surfaces. Energy beam welding uses laser technology to meld different metals together. Solid-state welding , or ultrasonic welding, connects thin sheets of metal or thermoplastic together through vibration at high frequency and under high pressure.
Welders face hazardous and potentially fatal circumstances when operating the appropriate machinery. For this reason, welders must take proper precautions, such as wearing the personal protective equipment, especially if procedures involve an open electric arc or flame. Personal protective equipment may include: leather gloves, long sleeve jackets, goggles, helmets, steel-toed shoes, gas masks, and ear muffs. Additionally, welders will erect translucent welding curtains to avoid bystander injury. Some environments may require a ventilated, full-body protective suit to avoid exposure to dangerous particulate matter, which could cause significant damage to body's processes.
A welder's certification embodies a procedure or qualification test measuring the aptitude of the candidate eligible for a career within the welding industry. Competent graduates should possess the skill and comprehension levels to follow the given instructions in order to produce the same results as the specific procedure outlines. In other words, a competent graduate will understand what it takes to produce quality results. Most welder qualification tests are given as pre-employment screenings, while a welder's certification ensures that the graduate understands the basic skills and codes to enter the workforce without discrepancy on the employer's behalf.