Презентация (Презентация по сварке для автомата (Arc welding))

- If everyone’s ready, let’s start.

- Good morning ladies and gentlemen. It’s good to see you all here. I’d like to start by introducing myself. My name is Alexsey Savelyev. I’m a student of group 7-73 of the Welding Technology department at the BMSTU (Bauman Moscow State Technical University). The subject of my presentation is “History of arc welding and present application.” I’ve chosen to speak about this because nowadays arc welding has a wide application in many different industries and the study of this welding type is important for the smooth operation of equipment.

Welding is a technique used for joining together two or more metallic parts usually through the application of heat.

Arc welding refers to a group of welding processes that use a welding power supply to create an electric arc between an electrode and the base material to melt metals at the welding point. The welding region is sometimes protected by some type of inert gas, known as a shielding gas, and filler material is sometimes used as well.

Power supplies

Arc welding can use either direct (DC) or alternating (AC) current. Suppling the electrical energy is necessary for arc welding processes, so a number of different power supplies can be used. The most common classification is constant current power supplies and constant voltage power supplies. In arc welding, the voltage is directly related to the length of the arc, and the current is related to the amount of heat input. Constant current power supplies are most often used for manual welding processes such as gas tungsten arc welding and shielded metal arc welding, because they maintain a relatively constant current even as the voltage varies. This is important because in manual welding, it can be difficult to hold the electrode perfectly steady, and as a result, the arc length and thus voltage tend to fluctuate. Constant voltage power supplies hold the voltage constant and vary the current, and as a result, are most often used for automated welding processes such as gas metal arc welding, flux cored arc welding, and submerged arc welding. The type of current used in arc welding also plays an important role in welding.

There are two types of applied electrodes: consumable and non-consumable.

Consumable electrode methods

One of the most common types of arc welding is shielded metal arc welding

(SMAW), which is also known as manual metal arc welding (MMA). Electric current is used to create an arc between the base material and consumable electrode, which is made of steel and is covered with a flux that protects the weld area from oxidation and contamination by producing CO 2 gas during the welding process.

Non-consumable electrode methods

Tungsten inert gas (TIG) welding, is a manual welding process that uses a non-consumable electrode made of tungsten, an inert gas mixture, and a separate filler material. Especially useful for welding thin materials, this method is characterized by a stable arc and high quality welds, but it requires significant operator skill. It can be used on nearly all weldable metals, though it is most often applied to stainless steel and light metals.

Hazards

Welding, without the proper precautions, can be a dangerous and unhealthy practice. However, with the use of new technology and proper protection, the risks of injury and death associated with welding can be greatly reduced.

There are several hazards, which can lead to problems with health: high temperature, sparks, UV-rays, ozon, harmful gases and aerosols.

Safety issues

Because many common welding procedures involve an open electric arc or flame, the risk of burns is significant. To prevent them, welders wear protective clothing in the form of heavy leather hand gloves and protective long leather jackets to avoid exposure to extreme heat and flames.

The brightness of the weld area leads to a condition called arc eye in which ultraviolet light causes the inflammation of the cornea and can burn the retinas of the eyes. Face shields with dark face plates are worn to prevent this exposure, and in recent years, new helmet models have been produced that feature a face plate that self-darkens upon exposure to high amounts of UV light.

During the work, it may need to move hot workpieces from one place to another or reverse it. In this case workers used pilers to prevent burns.