Analyze the Gap between the Valve Industry at Home and Abroad, Reform and Innovation to Promote Development
With the rapid development of China’s economy, the vacuum valve industry, as a national industry, has experienced rapid development throughout the country after several years of ups and downs. It has become one of the main industries that have developed rapidly in the domestic machinery industry. Although the valve industry in China has developed faster, 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-end; due to the late start of the domestic valve industry, 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. Coupled with the limitation of automation control level, there is a certain gap between developed countries and foreign countries in terms of high-end valve technology. What is the reason for this problem?
1. The gap in technological innovation capabilities
Insufficient technological innovation ability is a stumbling block hindering the development of our valve industry. At present, the design level of my country’s valve industry is not high. Although domestic backbone enterprises have certain R&D conditions, the R&D centers of most valve companies are limited by personnel and facilities, and lack sufficient capital investment. R&D and technical service capabilities are relatively closed. According to the needs of the company, it only serves the company, and performs design and process preparation based on sales orders. The functions are relatively simple; such as on-site technical processing in the valve production process, or engaged in a small amount of new product development. Compared with developed countries, the domestic valve design level is far behind.
At present, many domestic valve companies rarely innovate after introducing advanced technology. 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 companies have modern equipment that can realize automatic operation, and even some Western companies are dwarfed. But most companies have outdated equipment and poor working conditions. At present, Chinese valve companies can cast steel, iron, aluminum, copper, composite materials and other valve products, but due to the backward casting technology, 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 manufacturers cannot independently carry out effective analysis of the earthquake resistance of valves, and these manufacturers must entrust design schools to carry out seismic analysis. Only a few manufacturers have a relatively complete grasp of valve stress calculation and seismic analysis, valve fatigue analysis, As well as impact resistance analysis, to a certain extent, it has restricted the improvement of domestic manufacturers’ research and development capabilities. The degree of cooperation between domestic production, education and research is also low, and the technical content of self-developed products is also low. Although some colleges and universities and research and design institutes have departments, departments, and offices to carry out valve technology research, they only focus on valves in the entire installation. The role and required characteristics of the valve put forward technical requirements, and do not develop 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 them are key 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 usually have dedicated R&D centers. In contrast, 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 applied to valve products is quite complete: both theoretical analysis and prediction of the advanced performance of new products and new technologies can be carried out through analytical means, and the results can be predicted by experimental methods. Perform verification and verify the correctness of its analysis methods based on statistical data at the same time, so as to obtain a series of effective valve performance and technical characteristics analysis methods. This type of method is applied to subsequent valve technology development, and even reduces R&D costs. The research results are more effective.
Although many companies have obtained many national patents for their valve products, many of them are only utility patents, and the technical content is not high. Many patents only have partial improvements in the structure, without substantial improvements in inventions. There are still imitations and plagiarisms. Since many valve users have stayed with traditional products for many years, many of the internal and external structures of the products have not been substantially improved or improved for many years.
The current level of control of actuators for valve products in my country is also poor. The performance and control level of the domestically produced valve supporting drive actuator is only the level of the foreign countries in the 1990s, its action sensitivity is poor, and the overall level of automation control capability and reliability is relatively lagging. In contrast, a series of control capabilities such as signal acquisition, signal comparison, signal amplification, and signal return lag behind those of developed countries.
In fact, in terms of technical level, we have no big gap in the design and material application of conventional valves compared with well-known foreign companies, and there is no insurmountable gap in the manufacturing process. What is the difference? However, the actual situation is that the word “seriousness” is bad. There is such a product that was originally a patented product of a German company’s water valve. It was produced by several different companies at the same time. One is a foreign company, one is a Taiwan-funded enterprise, and the other It is a domestic company. With the same product picture, the valves produced are different. The internal quality and appearance of the first two companies are better than domestic ones. What is puzzling is that these companies all produce this product in China, and the castings are all from domestic factories, but the results are very different. In a sense, there is a big gap between our business philosophy and pursuit of goals and foreign-funded enterprises, especially in the product rough processing technology that does exist certain problems, which is also our reflection.
The practice of foreign companies is different from that of Chinese companies. Chinese companies first start infrastructure construction, expand production plants, and add production equipment. The plants are also expanded and expanded again, pursuing large and complete, modern style, and only want to expand the scale of production. Due to the R&D and investment of new products, the product stamina is seriously insufficient, and most of the products produced are imitations, only ordinary low-end products are produced, too much energy is invested in market operations, and improper means are used to engage in product promotion competition, thus lacking core competition force. When many domestic companies are engaged in research and development, they often refer to the design of other manufacturers, thus ignoring the importance of the original experimental data. In this way, the products developed have only appearance without real soul.
As the entire industrial system, there are also certain problems. Our R&D system is quite weak, but its innovation capabilities are relatively weak. Now some companies have many branches and joint ventures. Some companies invest in R&D capabilities and build scientific and technological teams. The investment in the establishment of R&D facilities and facilities is also small. In fact, the R&D investment is very large. At present, the entire industry in the R&D team, R&D methods, R&D product testing measures, and type test equipment are not enough to support our valve industry. Implement scientific research and development and develop new products, not to mention the development of high-end products.
At the same time, we must be soberly aware that with China’s accession to the WTO for several years, my country’s economy has gradually integrated with the world economy, and powerful foreign-funded enterprises have rushed to the valve market in China. These overseas legions have strong capital and high technology, and have The rich business strategy poses a certain threat to the Chinese valve market, and it is also our main competitor in the valve industry. At present, they are acquiring valve companies in China, recruiting high-paying technical design talents in the valve industry, and using well-known brands to seize the high-end valve market in my country. Some invest and build factories in my country, some relocate their headquarters to China, and some establish R&D centers in China.
2, the gap in processing technology
Foreign countries: In order to meet the radiation resistance requirements of nuclear-grade valve sealing materials, the welding process, such as the German KSB company, has widely adopted special solder powder for cobalt-free welding. The method is to sinter the solder powder and heat treatment after welding. Valve products are designed according to the requirements of operating conditions, and high temperature and high pressure gate valves mostly adopt parallel double gate structure.
The French Weiland Valve Company preheats the welding process and equipment before welding. The automatic welding and post-welding treatment are completed in the same equipment or the same processing line. The temperature can be automatically controlled regardless of the pre-welding, welding and post-welding treatments. , To ensure the welding quality, simplify the welding process, and improve the welding efficiency, especially for relatively complex welds (such as straight and curved connections to achieve automatic welding).
While the domestic valve welding technology is backward, and some still use outdated welding methods, the welder’s technical level is low, and the welded materials are also ordinary materials, which cannot meet the special valve design requirements. Many companies are busy with production and sales all day, and seldom conduct research and improvement on the process. Generally, there are many ordinary valves produced, and no medium and high-grade valves are involved at all, so the technical level is average.
The standards are backward and the parameters are not mastered enough. In terms of design and manufacturing standards such as ASMEBPVC and RCC-M, foreign manufacturers have systematically mastered these specifications and implemented them in design and manufacturing. However, most of the domestic valve manufacturers only partially master them, without systematic and comprehensive in-depth research, and have not fully grasped the functions, parameters, and requirements of various valves on the system. Foreign valve manufacturers know the location, function, parameters, requirements, and difficulties of each valve.
“At present, the domestic equipment capacity is generally too small, and can only produce forging steel blanks below 3″ (DN100), so the equipment capacity needs to be improved.
In the application of the new technology of die forgings, because the internal quality of forgings is better than that of steel castings, high-end valves with medium and small diameters of 4~6” need to use forging hammers of more than 3 tons, 4,000 tons of friction presses or 10,000 tons of hydraulic presses. The production of high-end valves requires an increase in the level of forging equipment capabilities. The valve materials produced by foreign companies are mainly high-temperature alloy steel F91 and F22, while high-pressure valves are mainly forged parts. The forging parts adopt a more flexible design, which can be seen on the job site. Many free-forged multi-body tailor-welded structure valves are used to ensure the reliability and economy of the product under the premise of reliable welding and non-destructive testing. Die forging is used for gate valves with large batches below 600Lb. And welding can ensure the tightness of the material of the blank, the valve does not have many defects such as porosity and looseness due to casting, and can reduce the material waste of free forging, and the economy is greatly improved.
Domestic: At present, most of the valve parts in the domestic industry are casting parts, and die forging is rarely used. Valve die forging with high pressure below 600Lb can be described as phoenix angle. As far as I know, the valve adopts die forging. Hengdian Machinery, Nanjing Huaning, Jianhu Dongfang Valve, Jinhu Jinshi Group have 1000-6000 tons pressure die forging equipment, and can also forge DN100 valve bodies. Using die forgings, the cost of forging is relatively high, but the internal quality of the processed valve is absolutely first-class. Recently, Harbin Valve has applied forging and welding technology to the large-diameter, high-temperature and high-pressure power station stop valve for the first time in China. The whole adopts die forging valve, which is suitable for high temperature and high pressure corrosive medium pipelines. The integral die forging valve retains the original welding flange valve. The beautiful appearance eliminates the hidden dangers of welding seams, increases the strength of the valve body, and eliminates hidden dangers of weld corrosion resistance. At the level of forging steel, DN100 and DN600 reflect the gap between my country’s forging capacity and foreign countries.
There is a big gap between the existing domestic cast steel technology and foreign countries. If we use too many steel castings, there are also defects in the production technology of rough parts. High-end valves have strict requirements on the chemical composition content and uniformity of molten steel, and no slag inclusions and pores are allowed. Foreign countries adopt refining processes and use more AOD furnaces (argon-oxygen decarburization refining) for smelting. The principle is to use a mixture of oxygen and inert gas instead of pure oxygen to blow molten steel, change the thermodynamic characteristics of the decarburization process, and reduce CO The partial pressure causes excessive oxidation of chromium. Intrusive blowing can remove non-metallic inclusions and harmful dissolved gases such as oxygen, nitrogen, and hydrogen. The AOD process is an advanced technology for the production of 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., and are mainly suitable for high-end valves Requirements for molten steel. In addition, the resin sand molding process is too much currently used, which is not as good as the ester-hard modified sodium silicate sand molding process. The sodium silicate sand process is basically an inorganic binder, which has less air volume, good sand mold retreat, and castings are not easy to produce pores and cracks , Is currently the first choice for high-end valve steel casting molding process.
3. Gap in quality management and equipment
Many domestic counterparts have backward production equipment, and they have remained at the level of equipment in the 1970s and 1980s. Some equipment has already passed the service life and is still operating at full capacity. Some bosses are reluctant to weed out old equipment in order to earn more money, and it is a long way to buy new equipment. Can the quality of processed products be guaranteed? Some are limited by funds, and are gradually adding numerical control and machining centers. However, there are not many companies that have formed numerical control processing in the industry, accounting for only about 20%.
Overseas: The quality of foreign valve products can generally meet the requirements of API, JIS, BS and other standards, and the casting blanks have high internal quality and high precision. They can be processed on special machines without refurbishment. They have beautiful appearance, clear castings and good sealing performance. There are many varieties and specifications of packing and gaskets, which can meet the requirements of different working conditions. The automatic control valve has stable performance parameters, which fully guarantees no leakage during use and accurate adjustment accuracy. The service life of general valves can reach 1 to 2 maintenance periods, or even longer.
For example, the French Bernard Electric Device Company sold 300 million yuan in 2005, and exports accounted for 70% of the sales. It has established a global sales network. my country’s metallurgical and oil and gas pipeline valves use a large number of the company’s electrical products. In the field of nuclear power, their supply is ranked second in the world. It is said that 80% of the nuclear power plants in my country’s Qinshan Phase II, Daya Bay and Tianwan Nuclear Power Plants are also their goods. Their management is very in place, the company’s parts processing records circulate with the parts, the production site is neat and tidy, and the two assembly lines are working in an orderly manner. Their screw processing adopts the rolling method, which has high efficiency and high surface finish. The processed parts are cleaned in a timely manner, and the station equipment is properly used, such as a plastic bag on each shaft, which is simple but practical, and avoids collisions and scratches between parts. The painting method of the parts is similar to that in China, but because the rough itself is smooth and the quality of the paint is excellent, the appearance effect and quality of the products after painting are quite good.
Foreign companies have complete and advanced quality control methods, complete hot and cold experiments, and use advanced coordinate measuring instruments. All kinds of flaw detection equipment are strictly inspected. Each link of quality assurance is also in place. Each part is clear in any process. The records are very detailed and the responsibilities are clear; the surface quality is also good, including forging quality, surface polishing, weld quality, almost eliminates bumps and scratches; cleanliness is also high, including workshop civilized production and environmental sanitation, dust prevention, rust prevention, and products The burrs in all parts of the parts, flashes are cleaned, polished, cleaned, and cleaned and dried before assembly, without leaving a trace. The employees are also dedicated and meticulous. The concept is high quality and price, mainly for high-end valves.
Although the domestic valve industry started the work of adopting international standards and joint design and joint development in the mid-1980s, and most of the products adopted international standards and foreign advanced standards, due to the gap in implementation, the current domestic valve product quality The level is still lower than the requirements of international standards. Mainly manifested in: the wall thickness of the blank is out of tolerance; the quality of the surface roughness of the casting is poor; the precision of the casting size is poor; the internal and external leakage of the general valve is serious, and even some valves cannot guarantee reliable operation during an overhaul period; the drive device