Hits:Updated:2020-05-14 10:05:56【Print】
The electromagnetic pilot head occupies an important place in the national economy, and many important basic economic constructions require the support and cooperation of the valve industry. It is an indispensable part in the machinery industry and promotes the development of machinery facilities at home and abroad. According to statistics from foreign industrial developed countries, the output value of valves is the sum of compressors, fans and pumps, accounting for about 5% of the output value of the entire machinery industry. At the same time, as an important part of major technical equipment, especially in power, petrochemical, metallurgy, urban water supply and drainage systems, valves play a key role, and the amount is very large. Due to the requirements of various working conditions, valves are widely used in various fields of national economy and people's livelihood.
With the rapid development of China's economy, the valve industry as a national industry has experienced rapid development over the years and has developed rapidly throughout the country. It has become one of the major industries in the domestic machinery industry. Although China's valve industry has developed rapidly, There are also many problems, the development level of the industry is low, the product technology content is low, and many products are still low-grade; because the domestic valve industry started late, it is still in the development stage, and the valve design, manufacturing, production and testing capabilities are lower than foreign advanced Many key valves still rely on imports. Many valves do not have core technology. With the limitation of automation control level, there is a certain gap in high-end valve technology compared with developed countries and foreign countries. What are the reasons for such problems? The following analysis :
1. The gap in the valve industry is obviously the key innovation and improvement
At present, the gap between China's valve industry and foreign valve industry is more obvious, and it also allows us to see our own shortcomings, so as to find the essence of the gap and problems, so as to improve and improve. What I have learned from the field in the industry and summarized in the relevant analysis data, there are four major comprehensive gaps: First, the gap in technological innovation capabilities; Second, the gap in processing technology; Third, the quality management and equipment The gap; the fourth is the gap in process management; specific can be analyzed from the following aspects:
1. The gap in technological innovation capabilities
The lack of technological innovation capabilities is a stumbling block that hinders the development of our valve industry. At present, the design level of China's valve industry is not high. Although domestic key enterprises have certain R & D conditions, most R & D centers of valve companies are restricted by personnel and facilities, and lack of sufficient capital investment. R & D and technical service capabilities are relatively closed, mainly because According to the needs of the enterprise, it only serves the enterprise, prints, designs and processes according to the sales order, and the functions are relatively simple; such as on-site technical processing in the production process of the valve, or engaged in a small number of new product development. Compared with the developed countries, the domestic valve design level is far behind.
At present, many domestic valve companies have rarely introduced innovations after introducing advanced technologies. When overseas customers visited China's heavy industry projects, such as papermaking and petrochemicals, they found that the valve products of many projects were only changed on the basis of Western design prototypes. The processing technology is also relatively backward, although some domestic valve manufacturing enterprises have modern equipment that can be automatically operated, and even dwarf some Western enterprises. But most enterprises have outdated equipment and a harsh working environment. At present, Chinese valve enterprises can cast valve products of steel, iron, aluminum, copper, composite materials, etc. However, due to backward casting techniques, raw materials such as cast steel and cast iron are wasted in the production process, and environmental protection is also poor.
For example, most domestic valve manufacturers have not been able to independently conduct effective seismic analysis of valves, and these valve manufacturers must entrust design schools to conduct seismic analysis. Only a few valve manufacturers have a complete grasp of valve stress calculation and seismic analysis, and valve Fatigue analysis and anti-shock analysis have restricted the improvement of domestic valve manufacturers' R & D capability to a certain extent. The degree of domestic industry-university-research cooperation is also low, and the technological content of self-developed products is also low. Although some colleges and universities and research and design institutes have specialties, departments and offices to carry out valve technology research, but only for the valves in the entire device The technical requirements of the role and required characteristics do not initiate the research and development of valve product design and manufacturing technology. Even if there are design drawings, they often lack manufacturability and are not compatible with actual operations. Some of the key factors are due to the lack of actual verification methods. This is the main reason for the low overall technical level of domestic valve products.
Foreign valve companies with high technical level are usually equipped with special R & D centers. In comparison, they have strong funds, various related research institutions and professional and excellent technical engineers to support them, and these R & D centers are often equipped according to needs. There are specialized laboratories and testing institutions, and the computer application software for valve products is also quite complete: both theoretical analysis and prediction of new products and new technology advanced performance can be carried out by analytical means, and experimental methods can also be used to predict results Carry out verification and verify the correctness of its analysis method based on statistical data, in order to obtain a series of effective analysis methods of valve performance and technical characteristics, and apply such methods to the subsequent development of valve technology, so as to reduce research and development costs, Its research results are more effective.
Although many enterprise valve products have obtained many national patents, many patents are only practical patents, and the technical content is not high. Many patents have only partially improved the structure, and have not substantially improved the invention. Since many valve users have stayed with traditional products for many years, the internal and external structures of many products have not been substantially improved and improved for many years.
Another example is that the control level of valve actuators in China is poor. The performance of the domestically produced valve-driven actuators is only the level of the 1990s abroad, and its action sensitivity is poor, and the overall level of automation control capability and reliability is relatively lagging behind. With this, its signal acquisition, signal comparison, signal amplification, signal return and other control capabilities lag behind those of developed countries.
In fact, as far as the technical level is concerned, there is not much difference between the design and material application of conventional valves and well-known foreign companies, and there is no insurmountable gap in the manufacturing process. What is the difference? The situation is that the word serious is serious. There is such a product. It was originally a patented water valve product of a German company. Several different companies produced it at the same time. One was a foreign company, one was a Taiwan-funded company, and the other was a domestic company. . The same product picture, but the actual valve produced is different. The first two companies have better internal quality and appearance than domestic ones. What is puzzling is that these companies all produce this product in China, and the casting blanks are all from domestic factories, but the results are very different. In a sense, there is a big gap between our business philosophy, the pursuit of goals and foreign-funded enterprises, especially if there is indeed a certain problem in the product blank processing technology, we also reflect on it.
The practices of foreign companies are different from those of Chinese companies. China ’s companies first engage in infrastructure, expand production plants, and add production equipment. The plants are also expanded and expanded, pursuing large and comprehensive, modern style, and only want to expand the scale of production, ignore After the research and development and investment of new products, the product's stamina is seriously insufficient, and most of the products produced are imitations, only ordinary low-end products are produced, too much energy is put into the market operation, and improper means are used to engage in product marketing competition, thus lacking core competition force. When many domestic enterprises engage in R & D, they mostly refer to the design of other manufacturers, thus ignoring the importance of the original experimental data, so that the products developed have only appearance but no real soul.
As the entire industrial system also has certain problems, our R & D system is quite weak, but its innovation ability is relatively weak. Nowadays, some enterprises have many factories and affiliated enterprises. Some enterprises invest in R & D capabilities and the construction of scientific and technological teams. In addition, there is also little investment in the establishment of R & D means and facilities. In fact, R & D investment is very large. At present, the entire industry is not enough to support our valve industry in R & D teams, R & D means, product testing measures, and type test equipment. The implementation of scientific research and development and the development of new products, let alone the development of high-end products.
At the same time, we must soberly realize that as China has entered the WTO for several years, China's economy has gradually been in line with the world economy, and foreign companies with strong strength have rushed to the Chinese valve market. These overseas legions have strong funds and high-tech, but also have Abundant business strategies, intangible pose a certain threat to the Chinese valve market, and are also our main competitors in the valve industry. At present, they are acquiring valve companies in China, recruiting technical design talents in the valve industry with high salary, and using well-known brands to seize the high-end valve market in China. Some invest in and build factories in China, some move their headquarters to China, and some set up R & D centers in China.
2. The gap in processing technology
Abroad: In order to meet the radiation resistance requirements of nuclear grade sealing materials, special welding powder has been widely used for cobalt-free welding in German welding company KSB. The method is to sinter the welding powder and heat-treat after welding. The valve products are designed according to the requirements of the working conditions, and the high temperature and high pressure gate valves mostly adopt the parallel double gate structure.
The French Welan valve company pre-welds the welding process and equipment, and the automatic welding and post-welding processing are completed on the same equipment or the same processing production line. The temperature can be automatically controlled regardless of the pre-welding, mid-welding and post-welding processing , To ensure the welding quality, simplify the welding process, improve the welding efficiency, especially for relatively complex welding seams (such as straight line and curve connection to achieve automatic welding) to achieve automatic welding.
The domestic welding technology is backward, some of them also use the old welding method, the welder's technical level is low, the welding materials are also ordinary materials, and can not meet the special valve design requirements. Many enterprises are busy with production and sales all day long, and rarely carry out research and improvement on the process. Generally, there are many ordinary valves, and no middle-to-high-end valves are involved at all, so the technical level is average.
Standards and standards are backward, and the parameters are not mastered enough. In terms of mastering design and manufacturing standards such as ASMEBPVC and RCC-M, national foreign valve manufacturers have mastered these specifications more systematically and implemented them in design and manufacturing. Most domestic valve manufacturers are only partially mastered. There is no systematic and comprehensive in-depth research, and they have not fully mastered the functions, parameters and requirements of various valves on the system. Foreign valve manufacturers are well aware of the location, function, parameters, requirements and difficulties of each one.
At present, the domestic equipment capacity is generally too small, and it can only produce forged steel blanks and textiles below 3? (DN100), so the equipment capacity needs to be improved.
In the application of the new technology of die forgings, due to the inherent quality of the forgings being better than that of the steel castings, the high-end valves with small and medium diameters need to be 4 ~ 6? . The production of high-end valves requires an increase in the capacity of forging equipment. The materials of valves produced by foreign companies are mainly high-temperature resistant alloy steels F91 and F22, and the high-pressure valves are mainly forged parts. The forged parts are designed with more flexibility, and many free-forged multi-body tailor-welded structures can be seen at the work site The valve, in this way, guarantees the reliability and economy of the product under the premise of relatively reliable welding and non-destructive testing. Forging gate valves of less than 600Lb in large batches by die forging and welding to ensure the tightness of the material of the blank, the valve does not have many defects such as porosity and looseness caused by casting, and can reduce the waste of free forging materials and is economical. To improve.
Domestic: At present, most of the domestic industry's valve bad parts are castings, and few die forgings are used. Valves under 600Lb with high pressure can be described as phoenix phosphorus. According to my understanding, the valve uses die forging. Hengdian Machinery, Nanjing Huaning, Jianhu Dongfang Valve, Jinhu Jinshi Group, etc. have 1000-6000 tons of pressure die forging equipment, and can also forge DN100 valve bodies. The die forging is used, and the forging cost is relatively high, but the inherent quality of the processed valve is absolutely first-class. Recently, Haobao Valve applied forging and welding technology to the globe valve of large-caliber high-temperature and high-pressure power station for the first time in China. The die-forged valve is adopted as a whole, which is suitable for high-temperature and high-pressure corrosive media pipelines. Beautiful appearance, eliminate the hidden danger of welding seam brought by welding, increase the strength of valve body, and eliminate the hidden danger of corrosion resistance of weld seam. According to the country, at the level of forged steel, DN100 and DN600 reflect the gap between China's forging capacity and foreign countries.
There is a big gap between this domestic existing steel casting technology and foreign countries. If we use too many steel castings, the production technology of the blanks is also flawed. The high-end valves have strict requirements on the content and uniformity of the chemical composition of the molten steel, and no slag inclusions or pores are allowed. Abroad adopts refining technology and uses more AOD furnaces (argon-oxygen decarburization refining) for smelting. The principle is to replace pure oxygen with a mixed gas of oxygen and inert gas to blow molten steel. Partial pressure causes excessive oxidation of chromium. Intrusive spraying can remove non-metallic inclusions and harmful dissolved gases such as oxygen, nitrogen, and hydrogen. The AOD process is an advanced technology for producing ultra-low carbon stainless steel and blunt high-quality alloy steel. The steel castings produced therefrom have excellent mechanical and technological properties (higher mechanical properties, improved impact toughness), etc., which are mainly suitable for high-end valves Requirements for molten steel. In addition, the resin sand molding process is currently used too much, and it is not as good as the ester hard modified water glass sand molding process, and the water glass sand process is basically an inorganic binder, with less gas generation, good sand mold yield, and castings are not prone to blowholes and cracks. , Is currently the first choice of high-end valve casting steel molding technology.
3. Gaps in quality management and equipment
Many domestic counterparts have lagging behind in production equipment, and have stayed at the level of equipment from the 1970s to the 1980s. Some equipment has already passed the service life. Leather care is still running at full capacity. In order to make more money, some bosses are reluctant to phase out old equipment and buy new equipment. The quality of the processed products can be guaranteed? Some are limited to funds, and they are also adding CNC and machining centers, but CNC processing enterprises have been formed so far. Not many in the industry, only about 20%.
Foreign: The quality of foreign valve products can generally meet the requirements of API, JIS, BS and other standards, and the inherent quality of the cast blank is high, the precision is high, and it can be processed on special machines without refurbishment. There are many types of fillers and gaskets, which can meet the requirements of different working conditions. The automatic control valve has stable performance parameters, fully guarantees no leakage during use, and has accurate adjustment accuracy. The service life of general valves can reach 1 ~ 2 maintenance periods, or even longer.
For example, the French Bernard Electric Equipment Company sold 300 million yuan in 2005, and exports accounted for 70% of sales. It has established a global sales network. China's metallurgical and oil and gas pipeline valves use this company's electrical equipment products in large quantities. In the field of nuclear power, their supply ranks second in the world. It is said that 80% of the nuclear installations in Qinshan Phase II, Daya Bay and Tianwan Nuclear Power Plants in China are also their goods. Their management is in place. The company's parts processing record sheets are circulated with the parts. The production site is neat and tidy. The two assembly lines are working in an orderly manner. Their screw processing uses rolling method, high efficiency, high surface finish of parts. The processed parts are cleaned in a timely manner and the station appliances are properly applied. For example, a plastic bag on each shaft is very simple, but it is very practical and avoids collision and scratches between parts. The coating method of the parts is similar to that in China, but due to the smoothness of the blank itself and the high quality of the paint, the appearance and quality of the products after painting are quite good.
Foreign companies have complete and advanced quality control methods, hot and cold experiments are fully equipped, and advanced coordinates are used to measure
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