Medicine bag was covered electrode metal core known as the welding cell. Welding core is generally a certain length and diameter of the wire. Welding, welding core has two effects: first, conduction welding current, arcing the electricity converted into heat, the second is the core itself is melted as a welding filler metal and the formation of the liquid base metal fusion weld. Welding electrodes, welding metal core part of the total weld metal. Therefore, chemical composition of welding core {a direct impact on the quality of the weld. Therefore, as the core electrode wire individually with the provisions of its brands and ingredients. If used for submerged arc welding, electroslag welding, gas welding, gas welding method for welding filler metal, then known as the wire.
Electrode coating is applied to the welding surface of the coating layer of the core. Coating in the welding consumables , decomposition of gas and molten slag, effect of mechanical protection, metallurgy and processing, the role of improving the process performance. Coating of the composition are: minerals (such as marble, fluorspar, etc.), ferroalloy and metal powder (such as ferromanganese, ilmenite, etc.), organic matter (such as wood flour, starch, etc.), chemical products (such as titanium white powder, water glass, etc.). Welding electrode coating is to determine the quality of the important factors in the welding process are the following roles:
First, enhance the stability of arc burning. Drug-free light skin is not easy to ignite arc welding. Can not be stable even if the ignition of the burn. In the electrode coating, generally contains potassium, sodium, calcium, and low ionization potential material, which can improve the stability of the arc to ensure the continuous welding process.
Second, protect the weld pool. Welding process, the air of oxygen, nitrogen and water vapor immersion weld, would adversely affect the weld. Not only the formation of pores, but also reduce the mechanical properties of the weld, and even lead to cracks. The electrode coating melted, resulting in a large number of gas enveloped the arc and weld pool, molten metal is reduced and air interactions. Weld cooling, the molten slag coating to form a layer covering the surface of the weld to protect the weld metal and to the slow cooling, reduce the possibility of porosity.
Third, to ensure that the weld oxygen to parathion impurities. Although the carbon steel welding rod  process was protected, but still it is inevitable that a small amount of oxygen into the bath, the metal and alloy oxidation, burning alloying elements, reducing the weld quality. Therefore, the electrode coating by adding a reducing agent (such as manganese, silicon, titanium, aluminum, etc.), so that the oxide reduction has entered the pool.
Fourth, additional alloying elements for the weld. Because of the high temperature arc, weld metal evaporation of alloying elements will be burning, reduce the mechanical properties of the weld. Therefore, it is necessary to weld coating of appropriate alloying elements added to make up for the burning of alloying elements, ensure or improve the mechanical properties of the weld. For some alloy welding, also needs to penetrate through the coating to the weld alloy, the weld metal and base metal composition can be close to, the mechanical properties to catch up even more than the basic metal.
Fifth, improve welding productivity, reduce splash. Electrodes are made leather medicine increase decrease droplet splash effect. Coated Electrode slightly below the melting point solder core solder, but the center of arc welding in the core area, high temperature, so the first core solder melting, melting a little bit later coating. Thus, in the electrode ends to form a short section of medicine leather tube, with the role of Arc force, the droplets hitting the pool on the straight, make it conducive to overhead position welding and vertical welding. In addition, the core coated with solder coating, the arc heat is more concentrated. Also, due to reduced metal loss caused by the splash and improve the deposition coefficient, also improved welding productivity. In addition, the welding process will also reduce the amount of dust.

The world's industrialized countries attach great importance to the development of welding technology and innovation. U.S. and German experts in the discussion of the role of the 21st century and direction of welding. Agreed that:
(1) Welding (to 2020) will remain an important manufacturing process technology, it is an accurate, reliable, low cost, and is connected by high-tech materials, methods.
There was no other method can be applied more widely than the welded connections of metal, and welding products increased by a greater added value.
(2) Welding Consumable  Technology (including connection, cutting, coating) present and future, has the largest variety of materials may be successfully processed into products that can be put into the market of choice for processing methods.
(3) Welding is no longer a "craft-call", it will gradually be integrated into the product life-cycle process, from design, development, manufacturing to maintenance and recycling at all stages.
(4) Welding shall be considered to improve the product life-cycle cost, quality and reliability are vital tool, but also to improve the competitiveness of products in the market have an important contribution.
The world's major industrialized countries attach great importance to research institutions to play the role of welding, the formation of university research institutes are basically three levels of business research and development system. The major industrial countries have set up Welding Institute, such as the British Welding Institute (TWI), United States, Edison Welding Institute (EWI), the French Welding Institute (FWI), Japan Institute of connection and welding (JRWI) Ukraine Barton Welding Institute (PEWI), University of Aachen, Germany Welding Institute (ISF) and the German Welding Society (DVS) distributed throughout the country under the welding research and training centers (SLV), etc., while South Korea's Welding research center is located in the Hyundai Research Institute of Science and Technology (KAIST) Korea Industrial Technology Research Institute KITCH within the production. They all belong to the national welding research institutions.
Abroad in recent years, the development of welding technology can be used following the industrial robots, welding and laser welding technology of new power development process such as a brief description of several examples of the importance of integrating production and research. Japan's first international in 1972 after the global oil crisis, in order to improve its auto industry in the international competitive position, began to introduce and absorb the U.S. robotics, production and research with government funding to develop their own industrial robot industry, the Government application of domestic robot manufacturers to give tax concessions, and soon several technology a strong electrical / electronics companies in transition to become the backbone of Japan's industrial robot business, such as Yasukawa (motor), Panasonic (electrical), FANAC (NC), etc. . From the 20th century, the late 70's to 80 to 15 years, the rapid development of industrial robots in Japan and the U.S. as the world's production and application of industrial robots, "Kingdom" in 2004, with 356,000 units have been all kinds of robots, the world's total 42% of the total. Application of the robot Japanese car industry is the largest industry, bringing its price competitive advantage. Korea in the late 20th century, began to develop 80 industrial robot technology in government funding and guidance, led by Hyundai Heavy Industries Group, to the late 20th century, 90 in 10 years to form their own industrial robot system, the current South Korea's automobile industry a large number of applications their own robot, and has been South Korea's entire production line welding robot cars into China. China from the 20th century, 80's, the state has invested several hundred million dollars of funds, spent nearly 20 years, but because of too much academic work has even one can be mass independent intellectual property rights with Chinese enterprises for industrial robots not established, forming a huge contrast.
Laser is considered to be the 21st century, new energy, laser technology reflect a country's industrial level. Application of laser welding is causing national attention. Germany, Russia, the United States, Japan, France, Italy and other countries attach great importance to the development of laser technology. Germany has the laser welding, laser cutting, laser + arc hybrid welding technology used in car production, especially in the production of aluminum cars, leading the development of the automobile welding technology. The German government attaches great importance to the development of laser technology, education and research in the Department of the Government set up a special department in charge of coordinating the development of laser technology. Has been formed in Germany, the Institute of Laser Technology laser applications co-Project Development, and laser host plant manufacturer of laser accessories laser application of joint enterprise to form a three-dimensional overlay network. From the Aachen University and Fraunhofer Institute of Laser (ILT) and the IPG jointly, the main development of semiconductor lasers and fiber laser FL (DDL) and the University of Stuttgart and the Institute of Optical processing tools (IFSW) and the co-Trumpf, the main research and development of disc type of laser. Germany, Rofin-Sina Corporation and Trumpf The company mainly produces CO2 lasers, HAAS company mainly produce solid (ND YAG) laser, which produced the new IPG fiber laser, Laserline diode laser company, the formation of competing and complementary laser technology R & D and production chain. Volkswagen, BMW, Mercedes Benz and U.S. Fortune (Meyer) is a German shipyard application of laser welding technology, business model. Volkswagen of Germany has laser welding technology into China, and Shanghai Volkswagen and FAW - Volkswagen car production line applications, and promote the application of laser welding technology in China. This led the German government to form a research and development of the host by the production of parts manufacturing and application technology development business model combination Combination of laser technology chain, it is worthy of study in China. The chain and the development of robot technology in Japan would be similar.
Arc  Welding Wires  is still the main method, and electric arc welding technology, progress is mainly driven by the development of power. Foreign enterprises attach great importance to the development of welding power and the power and arc physics and the development of welding technology combined. Whenever there is a new type of welding power sources are also introduced new control methods. For example, when there is power thyristor rectifier welding spatter on the launch of the CO2 waveform control to reduce the square wave AC welding power and welding power supply; when the inverter power supply after the introduction of variable polarity power supply, STT short circuit transfer welding power supply, etc.; and when the all-digital power supply and then the welding current and voltage appear wire feed speed control of the double pulse synchronized aluminum welding power and CMT "cold metal transition" welding power supply and so on. This shows not only the development of welding power circuit design, it is related to electrical technology, microelectronic technology, control technology, computer technology, arc physics, process technology, engineering and technical personnel of the joint and cooperation, we need a multidisciplinary team. The lack of domestic welding machine industry leading enterprises, the lack of such a team, is caused by slow development of the domestic welding machine, small businesses in low-end products only struggling to survive the main reason.
Friction stir welding is the early 20th century, 90 the invention by the British Institute of Solid State Welding of welding technology, which is a revolutionary innovation with, because the metal does not melt during welding, non-arc light and heat radiation, low energy consumption, efficiency high, deformation of the workpiece, and many of the advantages of a small, but speedy application. Now in aircraft, rockets, boats, cruise ships, train cars and other aluminum alloy structural manufacturing applied. Some domestic research institutes and universities have purchased the UK patent license to start their own innovation activities, and partially used in production.
In summary, the major industrial countries foreign government attaches great importance to the development of welding technology, they want to use the advanced welding technology to improve production quality, increase efficiency, reduce costs, in order to relatively low labor costs with the country market competition, which is a strategic tool.