Domestic Development Status of Forged Steel Valves

In recent years, detailed and thorough research and test verification on valves are conducted in scientific research institutes, universities, professional institutions, and manufacturing plants. China's low and medium end valves have absolute speaking right in the world. Under the guidance of China's technological research policies, we have actively engaged in the development and research of high-end valves and made great progress. Most products are comparable to similar products from international companies. A number of leading companies in the industry have emerged. At present, high-end valves used in LNG, hydrogenation, thermal power generation, nuclear foundation and aerospace can be made in China. In actual use, their stability and reliability are good, and they have been recognized by the industries and companies, for example, the integral forged nuclear-grade wedge gate valve ( Figure 1) and nuclear-grade swing check valve (Figure 2). The valve industry has entered an era of innovation and a critical period of innovative development. Some new national standards, industry standards, and group standards that follow also need to be updated, which requires the active participation of relevant parties.
 
Technical levels
China's mechanical and electrical products play a pivotal role in the international arena. With the popularization of products worldwide, the competition is unprecedentedly fierce. Valves are no exception. In terms of high-end valves, we still lack experience accumulation and theoretical support. Stability needs to be tested and the whole industry needs to work together.
  
After decades of hard work, the domestically produced valves can meet the needs of industrial development, and their complete set rate and technical indicators have been significantly improved. In recent years, although large-scale enterprises with annual output values of several billion have emerged in China's valve industry, valve enterprises are still dominated by small and medium-sized enterprises. Their management capabilities and levels, technological research and development, and experiments still need breakthroughs. The corresponding valve forging enterprises also need to make full efforts to business management, quality control, production costs reduction and timely delivery. In the next few years and for a long time, the demand for valves in various industries such as petrochemical, natural gas, metallurgy, electric power, and urban construction will continue to increase in China. Therefore, there will be a good prospect in the manufacturing of the valve.
   
                
Figure 1 Integral forged nuclear grade wedge gate valves


Figure 2 Nuclear grade swing check valves
 
The importance of the quality of the valve
The failure of a small valve can sometimes have a great impact, which not only causes economic losses but also pollutes the environment. In July 2014, a small valve failure on a tank truck caused a leak, and the gasoline leaked from the tank truck, forming a gasoline river with 100 meters. A small valve can cause such losses. Once a large valve fails, the loss is even more unimaginable. Therefore, regardless of the size of the valve, quality is very important. The rapid development of nuclear power in China has entered the third-generation technology stage, and the importance of valves has become more and more obvious. Valves exist in almost every system. A unit with one million kilowatts requires about 15,000 valves. Although the investment only accounts for about 2% of nuclear power plants, the annual maintenance costs account for about 50% of nuclear power plants.
 
Once the valve fails, the consequences will be unimaginable, and the key valve should be made of forged steel as much as possible. The quality of forgings is of utmost importance and must meet the requirements for procurement technical conditions and relevant standards. As a valve  manufacturer, a study must be well made in advance in quality assurance, resource allocation, and production management.
 
Qualification requirements for valve forging manufacturers
According to the different uses of the forged valve, the valve owner has strict requirements on the qualification of the supplier. Nuclear power is an industry that has developed rapidly in recent years, and valves being made in China has occurred in recent years. Its profit rate of return is relatively high. If you want to produce forgings for the matched part, you must have a production certification and service content approved by the National Nuclear Safety Administration. Quality supervision is conducted regularly and irregularly by national authorities, engineering companies, owners and other review agencies for many times every year. The qualifications of relevant personnel for important positions in the enterprise (such as non-destructive testing, welding, and inspection personnel) must also meet the requirements and must obtain an operating certificate. At the same time, the valves supplied must not exceed the scope of design, manufacturing and supply covered by the certificate. An enterprise which is certificated with civil nuclear power production must also obtain a certificate for military nuclear power production before they can start manufacturing military nuclear power products. A factory without ASME NPT certificates can not supply for the API project.
 
Large foreign valve purchasing companies also require their suppliers to obtain corresponding certificates, such as CE certification, EMERSON, BP two-party certificates, etc. Military management system qualification certificates, confidentiality certificates, and second-party audit certificates are required for suppliers who supply military products.
 
In short, even if a manufacturer is capable of producing valves technically, it doesn't mean that valve and tee series of products can be manufactured. We must know whether it is necessary to obtain second or third-party certification.
 

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