There are several types of welding, as well as the corresponding basic knowledge.

In general: 1Manual arc welding, argon arc welding, electroslag pressure welding, flash butt welding, oxyacetylene flame gas welding and cutting, and carbon dioxide protection welding are commonly used in civil engineering for steel structure installation and non-ferrous metal welding.

2.Plastic welding is mostly used for hot melt welding of various engineering plastics, in which plastic bonding should also belong to the welding process. 3. The welding of shipbuilding boilers and various pressure vessels requires higher welding process requirements and stricter technical requirements, on-site operations, and uses special processes such as manual arc welding, argon arc welding, carbon dioxide protection welding, and electroslag welding.

3.There are also ultrasonic welding, first-class welding, etc., which are special welding technologies under special processes, and their uses are limited in actual operations, and they are no longer classified. The above is more one-sided, because the scope of welding technology is compared with the welding process, the topic is too broad and the technology is different from the process, and different processes can cause the same technical results, I hope the questioner can distinguish it!

In production, we generally divide welding into three categories: fusion welding, pressure welding, and brazing!

Welding is generally divided into fusion welding, pressure welding and brazing. Fusion welding achieves intermolecular bonding, while brazing utilizes surface tension.

Welding, also known as welding, is a manufacturing process and technology that joins metals or other thermoplastic materials such as plastics by means of heat, high temperature or high pressure. Welding achieves the purpose of bonding through the following three ways:

1. Fusion welding - heat the workpiece to be joined to make it partially melted to form a molten pool, the molten pool will be joined after cooling and solidifying, and the melt filler can be added to assist if necessary, it is suitable for the welding of various metals and alloys, without pressure.

2. Pressure welding - the welding process must apply pressure to the weldment, which belongs to the processing of various metal materials and some metal materials.

3. Brazing - using metal materials with lower melting point than the base metal as brazing metal, using liquid brazing metal to wet the base metal, filling the joint gap, and diffusion with the base metal to achieve link weldments. It is suitable for the welding of various materials, and also suitable for the welding of different metals or dissimilar materials.

There are many types of energy** in modern welding, including gas flames, arcs, lasers, electron beams, friction and ultrasonics. In addition to being used in factories, welding can also be performed in a variety of environments, such as in the field, underwater, and in space. Welding can be dangerous to the operator wherever it is, so proper precautions must be taken when performing welding.

The possible injuries to the human body caused by welding include burns, electric shock, vision damage, inhalation of toxic gases, excessive ultraviolet radiation, etc.

First, the basic knowledge of electric welding: it is a high-power transformer made of the principle of inductance, a power supply (which can be DC or AC) that turns 220V AC into low voltage and high current (can be DC or AC), the inductance will produce huge voltage changes when it is turned on and off, and the high-voltage arc generated by the positive and negative poles in the instantaneous short circuit is used to melt the solder on the welding rod to achieve the purpose of combining them. Welding transformers have their own characteristics, that is, the voltage drops sharply after the electrode is ignited.

The adjustment of the working voltage of the welding machine, in addition to the one-time 220 380 voltage conversion, the secondary coil also has a tap conversion voltage, and it is also adjusted with an iron core, and the adjustable iron core welding machine is generally a high-power transformer.

Second, the details are as follows: welding technology is a common method to change the metal structure and connecting parts, with the continuous development of industrial technology, manual arc welding, argon arc welding and other arc welding technology is more and more widely used. The technical level of the welder plays a decisive role in the quality of the welding.

At the same time, accidents caused by personal illegal operations are not uncommon.

Welding safety. 1. Risk factors of welding.

Welders should come into contact with electricity, flammable and explosive gases, flammable liquids, pressure vessels, and aerial work when working. In the welding process, harmful gases, metal vapors and fumes will also be generated; There is also the radiation of arc light, the high temperature of the welding heat source, etc. If safety operating procedures are not strictly followed, it may cause electric shock, burns, fires, **, and even occupational diseases.

Causing losses and harm to individuals, businesses, and countries.

2. Welder "six defenses":

During the welding work, it is necessary to prevent electric shock, fire prevention, explosion prevention, poison prevention, radiation prevention, and fall from height.

Protection against electric shock. Arc welding equipment must be grounded; The welding torch should have reliable insulation; The wiring, repair and inspection of arc welding equipment should be carried out by an electrician; The welder's work clothes, gloves, and insulated shoes should be kept dry; When replacing the welding rod, wear gloves and avoid contact between the body and the weldment; The welded cable must be well insulated, and the cable should be avoided from being burned or smashed when working;

Fire and explosion proof:

Before operation, flammable and explosive materials should be removed within 10 meters before and after the welding and cutting site, and non-combustible materials should be used to accept sparks. The electrical welding operation site must be equipped with at least two 8kg dry powder fire extinguishers, fire extinguishing sand, and no less than 50 liters of fire extinguishing water.

The electrode head and the weldment after welding should not be thrown casually; Take cooling measures such as sprinkling water in a timely manner. You must carry a portable gas check alarm with you, and the alarm point of the portable meter is.

After the operation, the construction site must be thoroughly cleaned, sprinkled, and kept for 1 hour to confirm that there is no danger before leaving.

Prevention of harmful gas and soot poisoning:

During welding, the surrounding air is often polluted by some harmful gases and dusts, such as manganese oxide, zinc oxide, hydrogen fluoride, carbon monoxide, etc. Long-term breathing may cause occupational diseases such as welders' pneumoconiosis.

Anti-poison measures: The welding site should be well ventilated. Avoid multiple welders crammed together. Wear protective gear.

Radiation protection: Radiation can stab the eyes and burn**. Wear an electric welding mask during construction; wear welder labor protection equipment;

Anti-Falling from Heights:

In our country, electric welding operations need to be licensed, welders are the type of work that belongs to the access category, in the professional qualifications of skilled personnel, only five of the 81 types of work are accessed, and the welder is one of them, and the actual situation is that most of the industry practitioners are unlicensed operations. With the continuous standardization of technology and the relevant requirements of the industry, more and more people want to take a welding certificate, the advantage of the certificate is still very large, first of all, the salary of the certificate and the non-certificate are very different, often able to reach more than double or higher level. Therefore, the issue of short-term welder training has naturally become a concern for practitioners.

Welding as an industrial "tailor" is a very important means of processing in industrial production, the quality of welding plays a decisive role in the quality of the product, so, what is the future development of welding technology?

Industry outlook. With the development of production, welding is widely used in aerospace, aviation, nuclear industry, shipbuilding, construction and machinery manufacturing and other industrial sectors. After entering the 21st century, welding is an important part of the manufacturing industry, and the rapid development of the welding industry has brought unprecedented development opportunities, hydropower welding, argon arc welding, CNC and other technical types of work in the increasingly difficult employment situation is still outstanding.

At present, China consumes 300 million tons of steel every year (about tons of welded structure), and needs about 750,000 welding machines, and the welding industry will continue to grow in the next 8 10 years.