Current situation and development trend of welding

2022-10-01
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Current situation and development trend of welding technology in heavy machinery metal structure industry

current situation and development trend of welding technology in heavy machinery metal structure industry

China Construction machinery information

Guide: in recent years, with the rapid development of national economy, China's heavy machinery metal structure manufacturing industry has made remarkable achievements. China is not only a major steel consumer in the world, but also a major machinery manufacturing country in the world. According to the statistics of the international iron and Steel Association (IISI), the world steel output reached 1.03 billion for the first time in 2004

in recent years, with the rapid development of national economy, China's heavy machinery metal structure manufacturing industry has made remarkable achievements. China is not only a major steel consumer in the world, but also a major machinery manufacturing country in the world. According to the statistics of the international iron and Steel Association (IISI), the world steel output reached 1.03 billion tons for the first time in 2004, and the steel consumption was 935 million tons. China's steel output in 2004 was 272 million tons, accounting for about 26% of the global steel output. The annual steel consumption was 312 million tons, accounting for 33% of the global steel output, of which 160 million tons were used in welded structures, accounting for about 51% of the steel volume. In Europe and the United States and the former Soviet Union, the steel measured with a dial gauge accounts for about 60% of the steel used in welded structures based on two force columns, and more than 70% in Japan. It can be seen that there is still a certain gap between China and industrialized countries. According to relevant investigations, among the 160million tons of steel used for welded structures, the amount of steel used for metal structures in machinery manufacturing industry accounts for about 45% of the amount of steel. The rapid development of iron and steel industry has created a lot of development space for the sustainable development of welding technology in China's welding industry, especially in the heavy machinery metal structure industry. Entering the 21st century, China's heavy machinery industry is facing new challenges and opportunities. We should thoroughly improve the traditional welding industry with high energy consumption, high consumables, low efficiency, poor working environment and low degree of automation, promote the development of welding technology and industry towards high quality, high efficiency, energy saving, low cost, environment-friendly and automation, and strive to transform the comparative human resource advantage into scientific and technological competitive advantage, Promote enterprise progress and industrial upgrading

current situation of welding technology in the industry

1 Overview at home and abroad

welding technology is one of the key technologies for the manufacturing and installation of heavy machinery metal structure equipment, and has been widely used in the heavy machinery manufacturing industry in industrialized countries. Up to now, there is a big gap between China's heavy machinery welding technology and developed countries such as the United States (such as p H company), Germany (such as Symantec company), France (such as VAI company), Japan (such as Mitsubishi Heavy Industries, Komatsu Corporation, etc.). At present, the proportion of welded structural parts in these countries and regions is increasing day by day. Among them, the welding metal materials consumed by efficient welding processes such as automated and mechanized gas shielded welding and multi wire submerged arc welding account for about 50~70% of the total welding materials. Their welding production adopts mechanized, automated and efficient welding processes, which brings the effect of high welding production efficiency, good welding quality and strong international competitiveness

in China's heavy machinery metal structure industry, gas shielded welding, double wire submerged arc automatic welding, gantry welding machine, electroslag welding and other high-efficiency welding processes are increasingly used in large metal structure manufacturing enterprises. The metal structures completed by high-efficiency welding methods account for about 50~80% of their total weight. In small and medium-sized enterprises, CO2 gas shielded solid core welding wire, submerged arc automatic welding and other methods have also been applied. But in general, the advantage of low labor wages in China's heavy machinery manufacturing is being offset by the huge gap between low production efficiency and high quality cost, which should be paid enough attention to

2. Product situation

heavy machinery metal structure industry mainly provides heavy machinery and equipment for national large backbone enterprises and national key engineering projects. Key manufacturing enterprises in the industry, such as the first Heavy Machinery Group Co., Ltd., the second Heavy Machinery Group Co., Ltd., Taiyuan Heavy Machinery Group Co., Ltd., Dalian heavy industry Crane Group Co., Ltd., CITIC Heavy Machinery Co., Ltd., Zhengzhou coal machinery plant, Beijing coal machinery plant, Shanghai Zhenhua Port machinery company, Qiqihar second machine tool plant, etc., mainly manufacture large bridge and gantry cranes, 4~35m3 mechanical excavators 1~6m3 hydraulic excavator, large pressurized gasifier, hydrogenation reactor, large stage equipment, space launch tower, coke oven mechanical equipment, spiral welded pipe equipment, large reducer, hoist, stacker reclaimer, steel rolling and forging equipment, oxygen cylinder press, cement equipment, grinding, crushing machinery, water conservancy, engineering machinery, hydraulic prop, port machinery and environmental protection equipment

3. Steel for heavy machinery metal structure industry

for a long time, China's heavy machinery metal structure industry has mostly adopted domestic and foreign mature steel grades, such as Q235 series carbon steel, Q345, Q390 series low alloy steel, 20g, 16MnR pressure vessel steel, etc. In recent years, with the development of national key projects and the adjustment of product structure, the types and varieties of welding steel have been greatly improved. Common steel plates include: Q235, Q345, Q390 DuPont and Dow will still keep the original company name, 20, 35, 45, 15Mo3, 15CrMo, 13MnNiMoNbR, wel ten80c, A633D, 16MnR, 20g, 15MnVR, etc; Common stainless steel plates are: 0Cr18Ni9, 1Cr18Ni9Ti, 1Cr13, 2Cr13, 3Cr13, etc; Common aluminum plates include hard aluminum and aluminum alloy plates; Common forgings include 25, 35, 45, 40Cr, 42CrMo, 40CrNiMo, 40CrNi2Mo, 20MnMo, 42CrMnMo, 34CrNi3Mo, etc. The plate thickness is generally 1~300mm16 Calculate the difference between the experimental results in automatic and manual modes

with the continuous increase of steel types and varieties, the annual output of weldments has increased significantly. According to incomplete statistics, the annual output of welded parts of Qiqihar second machine tool plant in 2005 was about 10000 tons; The second Heavy Machinery Group Co., Ltd. is about 30000 tons; Taiyuan Heavy Machinery Group Co., Ltd. is about 50000 tons; CITIC Heavy Machinery Co., Ltd. exceeded 50000 tons; The annual output of Weldments of Shanghai Zhenhua Port Machinery Company is up to about 200000 tons. With its unique advantages, welded structural parts have replaced riveted structure and cast structure, and become the leading structure of metal structure equipment in heavy machinery industry

4. Welding process method

the heavy machinery metal structure industry has started, and the manual arc welding process method is generally used. In the 1950s, automatic submerged arc welding and electroslag welding processes were used, mainly for the welding of some thick plates, I-beams and cylinders. In recent years, through technological transformation, some large enterprises have successively applied advanced welding processes and methods such as double wire submerged arc welding, double wire narrow gap submerged arc automatic welding, gantry welding machine, roller submerged arc surfacing to meet the technical requirements of product manufacturing

with the transformation of welding technology in large backbone enterprises in China, gas shielded welding technology has been widely used in heavy machinery metal structure industry. It can be said that the gas shielded welding process is growing with the development of welding technology in the metal structure industry of heavy machinery. In the late 1980s, in order to meet the manufacturing requirements of large-scale mechanical technology and equipment for national key projects, introduce foreign advanced welding technology and equipment, and carry out technological transformation of large backbone heavy machinery enterprises, China's large-scale heavy machinery metal structure manufacturing enterprises cooperated with multinational companies in the United States, Germany, Japan and other countries to manufacture large-scale metal structures, and purchased foreign gas shielded welding equipment, welding materials and other equipment in batches, And carry out welder training. With the help of foreign mature technology and production process of gas shielded welding, China has formed the production capacity of gas shielded welding in China's large-scale metal structure industry, fundamentally changed the manufacturing technology level of heavy machinery metal and non deformable structure industry, and promoted the development of gas shielded welding technology in China. In the past ten years since the early 1990s, taking the first "national CO2 welding technology promotion and application exchange" as an opportunity, China held two consecutive national CO2 welding technology promotion and application exchanges in 2001 and 2004 respectively. The promotion and application of gas shielded welding technology in the heavy machinery metal structure industry has continued to develop steadily and vigorously, and the development and application ability of gas shielded welding technology has been enhanced, The application work has been extended from large machinery enterprises to small and medium-sized enterprises, and the application of gas shielded welding in large heavy machinery enterprises has also been extended from the production of cooperative manufacturing products to the production of ordinary products. Gas shielded welding equipment, welding materials and accessories are basically supplied domestically, and China's gas shielded welding industry has gradually formed

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