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the development trend of ship welding power source

looking forward to the 21st century, the most advanced high-tech, such as the latest achievements in the fields of computer numerical control, microelectronics, information sensing, industrial robots, plasma and high-energy beam physics, are widely used in welding technology and will become a reality.

in the early 1990s, my country's electric welding machine manufacturing industry set off a "power revolution". at that time, hundreds of home appliance welding machine manufacturers all over the country started to develop and sell inverter power supplies. at the same time, there were many public opinions. satisfied with the status quo of entering thyristor welding power from rotating dc arc welding power source, satisfied with the market share brought by "domestic fixed point", "introduced production line" (thyristor power source), etc., but also doubted about inverter power supply attitude, some foreign counterparts continue to warn their chinese counterparts in the tone of experts with ulterior motives, "don't blindly engage in inverter welding machines", china does not even have a device to detect igbt parameters. how can it be produced? what about igbt inverter welding machine? wait for the discussion.

 it is true that the adoption of a new technology will bring greater risks, and it is correct to warn everyone not to rush it, but the consequences of not rushing will cost many traditional enterprises in china's electric welding machine manufacturing industry. at the historical opportunity when new technology emerges, we can only use active guidance, summarize and discuss, encourage continuous correction of mistakes in development, and continue to achieve success in innovation.

at present, many welding machine manufacturers in my country have mastered the characteristics of different brands of igbts after nearly 10 years of unremitting efforts. the links and problems can be adapted to the working conditions in china, so that the inverter welding power source has developed into a multi-variety and multi-series brand. at the same time, the price on the market has gradually decreased, making the advantage of the performance and price ratio of the welding machine increasingly significant.

the face is going to fall behind. from table 1, the composition of electric welding machines from my country's "ninth five-year plan" to 2000 is compared with the production structure of electric welding machines in japan in 1991. it can be seen that the two are close, indicating that our welding equipment is about 10 years behind japan.

2 the development trend of marine welding power sources

arc welding power source is one of the important production equipment in the shipbuilding industry. the workload of arc welding in shipbuilding accounts for about 30% of the total construction time. at the same time, welding equipment is also the main energy-consuming equipment in shipyard production. therefore, the promotion and application of high-quality and low-energy consumption advanced welding equipment is an important aspect of the development of efficient welding technology.

in the 1960s, due to the emergence of semiconductor devices such as silicon rectifiers and thyristors, they were first used in welding power sources in advanced countries such as the united states, germany, and japan.

 in the 1970s, many countries developed high-frequency semiconductor devices, and developed pulse width modulation integrated circuits in the united states and japan, which basically determined the operating frequency of about 20khz.

after the 1980s, germany, the united states, japan and other countries successively developed insulated gate high-power field effect transistors, and later successfully developed insulated gate bipolar transistors, ie igbt tubes. at present, igbt modules have developed towards high withstand voltage (3.3kv) and high current (2000a), intelligent modules (ipm) with functions such as drive and current and voltage protection. at present, some inverter arc welding power sources have been matched with computer technology combined, we will develop in the direction of multi-function, intelligent modularization.

3 status and development of marine arc welding power sources in my country

 in the 1960s and 1970s, the main welding process of my country's shipbuilding industry was manual arc welding and submerged arc automatic welding, and manual arc welding accounted for more than 75%. therefore, most of the welding power sources are rotary dc arc welding machines and there are two types of ac welding machines. in the 1980s, the shipbuilding industry began to build export ships. in order to speed up the shipbuilding progress and improve the welding quality, the china shipbuilding industry high-efficiency welding technology steering group was established in 1986. guidelines for planning, classification guidance, and overall promotion. in the selection and update of welding equipment, it is clearly pointed out that the rotary arc welding machine should be phased out and replaced by energy-saving and high-efficiency welding equipment. with the continuous promotion for more than ten years, the composition ratio of welding equipment in shipyards tends to be reasonable. from table 2, it can be seen that the development focus of shipyards is co2 gas shielded welding machines.

table 1 composition ratio of electric welding machines in my country and japan

country year manual arc welding automatic and semi-automatic arc welding machine resistance welding machine special complete set of welding equipment

rotary dc welder rectifier welder ac welder

china 2000 4% 21% 42% 25% 7.5% 0.5%

japan 1991 19% 19.4% 21.5% 33.1% 6.8% 0.2%

table 2 composition ratio of shipyard welding equipment

year rotary welder rectifier welder ac welder submerged arc welder co2 welder

2002 2.08% 21.41% 10.32% 4.83% 31.24%

2001 6.5% 24.88% 11.47% 6.18% 27.33%

2000 9.11% 22.25% 22.67% 4.37% 38.89%

it is expected that in the marine system, the energy-consuming rotary dc arc welding machine will be completely eliminated at the end of the "tenth five-year plan" and replaced by a high-efficiency and energy-saving welding machine.

according to the survey of 26 shipyards by the steering group, in 1998, the total number of inverter welding machines in each shipyard was only 321, and according to the classification, there were 243 manual welding machines, 40 co2 welding machines, and 38 tig welding machines. , according to the classification of inverter welding machines using high-power switching devices, there are 209 thyristor inverter welding machines, 110 igbt inverter welding machines, and 2 transistor and field effect tube inverter welding machines.

judging from the application of inverter welding machines, jiangnan shipyard, chongqing shipyard and guangzhou shipyard international are widely used and effective. jiangnan plant is mainly used in large-scale engineering welding. xijiang shipyard and guijiang shipyard use inverter welding machines more but with poor results. due to the poor reliability of the welding machine due to the damage of the welding machine and repeated repairs, it is mainly used in the welding laboratory and a small amount in production. it can be seen from the survey that at that time, most shipyards were concerned about the promotion and application of inverter welding machines. they urgently hoped that inverter welding machine manufacturers should work hard to improve reliability and produce excellent products. the reliability of the inverter welding machine has been greatly improved, and its promotion and application in the shipbuilding industry will surely develop rapidly. however, some comrades still think that the inverter welding machine is relatively delicate, whether it can withstand the harsh welding conditions of the shipyard. the test is skeptical. the following four salient features can also be drawn from the survey:

(1) most tig welding machines are transistor inverter welding machines, and most co2 welding machines are igbt inverter welding machines. manual welding machines include both thyristor inverter welding machines and igbt inverter welding machines.

(2) the thyristor inverter welding machines produced before 1995 are the ones with more reflection problems, and the inverter welding machines produced in the last two years are the ones that reflect better.

(3) the inverter welding machines that are imported and produced by a few domestic factories are the ones with larger quantity and better effect.

(4) the quality of inverter welding machines of the same model varies greatly depending on the manufacturer.

after a period of promotion and application in the shipyard, it can basically be said that there is a certain basis for understanding, but the process of promotion and application must be gradual and deepen. inverter welding power source has become the most advanced welding power source recognized internationally. according to the opinions of domestic and foreign experts, inverter welding machine has 8 advantages, which can be arranged as follows according to their importance: ①good welding performance, fast frequency response, dynamic good characteristics are conducive to the realization of welding automation; ② light weight take the 400a welding machine as an example, the spin-on welding machine is about 370 kg, the thyristor rectifier welding machine is about 200 kg, the thyristor inverter welding machine is about 70 kg, and the igbt inverter welding machine is about 70 kg. about 40 kg; ③ high efficiency, up to 80%-90%; ④ high power factor up to 0.99; ⑤ small size; ⑥ reliable arc ignition and less spatter; ⑦ fast welding speed;

of course, in order to become a new generation product of shipyards, the inverter welding machine should have the adaptability and reliability required by the ship welding process in addition to the advanced features mentioned above. more importantly, in terms of reliability, the shipyard must be assured that it can guarantee a service life of more than 8 years, and the repair rate is reduced to about 1%. in addition, it must be competitive in price.

the development of inverter welding machine in my country has gradually moved towards a relatively normal development state after the "inversion heat" in 1993-94. a group of enterprises that have been tested from the "inversion heat" have clearly realized the development of inverter welding machine. long-term, arduous and complex. only by steadfastly re-development and improvement of technical processes, and paying close attention to product quality, especially reliability, can we be in an invincible position based on the market.

after in-depth research by the experts of our high-efficiency welding technology steering group of the shipbuilding industry, they agreed that the promotion and application of inverter welding machines in shipyards is the direction of development, and the promotion and application have a certain foundation. after the price is further reduced, the application of inverter welding machine in shipyards will have a leaping development after its adaptability to the needs of the shipyard welding process. due to the wide application of inverter welding machines, the modernization of welding equipment will be greatly improved. therefore, it has a significant impact on shortening the shipbuilding cycle, improving the quality of shipbuilding, improving economic benefits and improving labor conditions.

4 thoughts

 (1) in order to promote the application of inverter welding machines in shipyards, we must first increase the publicity of inverter welding machines, and introduce the performance characteristics of inverter welding machines in a realistic manner, because only the comprehensive and only after a correct understanding can the inverter welding machine be correctly selected and promoted. from the current lessons, choosing the correct promotion and application will be successful, otherwise it will suffer setbacks. in the process of selecting an inverter welding machine, the experience of four tests and two tests can be used, that is, the quality of the components used in the production plant and the purchase channels, the manufacturing equipment and testing instruments, the production process and management level, and the sales and maintenance services. network. the second test is to test the reliability and adaptability. the inverter welding machine used for the test must withstand the test for a long time and withstand the test of the harsh production environment of the shipyard.

(2) at present, the application of inverter welding machines in most shipyards is still in the trial stage, but the application of inverter welding machines in a few shipyards has begun to rise. we must carefully summarize good experience and promote it in the entire ship system.

(3) as a welding machine manufacturer, we must clearly see that shipyards have great potential to promote the application of inverter welding machines, but they must be prepared for long-term, arduous and complex thinking, and believe that there is no difficulty in the world as long as they are willing to climb. it is necessary to form a close partnership with the shipyard to achieve a win-win result together.

(4) at present, shipyards are vigorously promoting the application of co2 welding technology. this is where the inverter welding machine can play its specialty. it is recommended that shipyards should focus on promoting igbt-type inverter co2 welding machines when selecting co2 welding equipment.