Welding technology welding technology has been invented since more than a hundred years of history, industrial production of all important products, such as aviation, aerospace and nuclear energy industry products are inseparable from the production and manufacturing of welding technology.At present, the development of emerging industries forces welding technology to advance constantly. For example, the development of microelectronics industry promotes the development of micro-connection technology and equipment.The development of ceramic materials and composite materials has promoted the development of vacuum brazing, vacuum diffusion welding, spraying and bonding technologies.Therefore, welding technology will continue to develop with the progress of science and technology, mainly reflected in the following aspects:

1 energy at present, the welding heat source has a very rich, such as flame, arc, resistance, ultrasonic, friction, etc from, electron beam, laser, microwave, etc., but the research and development of the welding heat source has not terminated, its new development can be summarized into three aspects: first is on the improvement of the existing heat source, making it more effective, convenient, economy is applicable, in this regard, the development of electron beam and laser beam welding is significant;Secondly, a better and more efficient heat source is developed. The superposition of two heat sources is used to obtain a stronger energy density. For example, laser beam is added to electron beam welding.The third is energy-saving technology.Due to the large energy consumption of welding, many new technologies aimed at saving energy have emerged, such as solar welding and resistance spot welding, which use the development of electronic technology to improve the power factor of the welding machine. 

The application of the microcomputer control system of arc welding equipment in welding can analyze and control the welding current, welding speed, arc length and other parameters, display the welding operation procedures and parameter changes and keep the data, so as to give the exact information of welding quality.At present, various control systems based on computer include welding sequence control system, PID control system, optimal control system and adaptive control system.These systems are used in different welding methods such as arc welding, pressure welding and brazing.More and more attention has been paid to the application of computer software technology in welding.At present, computer simulation technology has been used to simulate welding thermal process, welding metallurgical process, welding stress and deformation.Database technology is used to establish welder file management database, welding symbol retrieval database, welding process assessment database, welding material retrieval database, etc.In the field of welding, the application of CAD/CAM is under constant development, and flexible manufacturing systems for welding have emerged. 

3 welding robot and intelligent welding robot is a revolutionary progress of welding automation, it broke through the traditional way of welding rigid automation, opened up a new way of flexible automation, welding robot's main advantages are: stability and improve the quality of welding, to ensure the uniformity of welding products;Increase productivity, 24 hours a day continuous production;The ability to work under harmful conditions for long periods of time improves workers' working conditions;Reduced the technical requirements for workers' operation;It can realize welding automation of small batch products.It provides technical basis for welding flexible production line.In order to improve the automation of welding process, in addition to control of arc weld automatic tracking and welding quality should also be real-time control, therefore need to test in the process of welding welding groove conditions, such as the back weld width, and depth of molten weld forming, etc., so as to timely adjust welding parameters, guarantee the good welding quality, this is the intelligent welding.The first development of intelligent welding focuses on the vision system, and its key technology is sensor technology.Although intellectualization is still in the primary stage, it has a broad prospect and is an important development direction.In recent years, the expert system of welding engineering has been deeply studied at home and abroad, and some commercial welding expert systems have been launched or are ready to be launched.The welding expert system is a computer software system with the knowledge and experience of an expert and the ability to solve welding problems.Based on this, the computer integrated management system of welding quality has also been applied in welding. Its content includes the analysis of the initial test data and data of the product, product quality inspection, sales supervision, etc. Its software includes the specific application of database, expert system and other technologies. 

Increasing welding productivity is an important driving force to promote the development of welding technology.There are two ways to improve the productivity: one is to increase the welding deposition rate.Manual arc welding of iron powder welding, gravity welding, lying welding and other processes;The multi - wire welding and hot wire welding in submerged arc welding are of this kind.For example, the process parameters of three-wire submerged arc welding are 2200A X 33V;1400A X 40V 1100A X45V, with small groove section and baffle or liner on the back, the steel plate of 50-6mm can be welded into shape at one time, with the welding speed reaching more than 0.4m/min, and its cladding efficiency is more than 100 times that of manual arc welding.Secondly, it is to reduce the groove section and the amount of deposited metal. The most outstanding achievement in the past 10 years is narrow gap welding.Narrow gap welding is based on gas shielded welding, and single wire, double wire or three wire are used for welding.No matter how thick the joint is, the butt joint can be used.For example, the thickness of the steel plate is from 50-300mm, and the clearance can be designed to be about 13mm. Therefore, the amount of deposited metal needs to be reduced by several times or tens of times, thus greatly improving the productivity.The main technical key of narrow gap welding is how to ensure the penetration of both sides and the automatic tracking of arc center on the groove center line.In order to solve these two problems, many different solutions have been developed in the world, and a variety of narrow gap welding methods have emerged.During electron beam welding, laser beam welding and plasma arc welding, butt joints can be used without wave opening, so it is an ideal narrow gap welding method, which is one of the important reasons why they are widely valued.