|Although in recent years the development of China's valve industry faster, but the overall level of the industry is still low, the low-tech products, many of the key parameters of the valve has a high dependence on imports. Some experts estimate that the level of our valves compared with foreign advanced countries to lag behind the 10 to 20 years. Not long ago, China's valve industry, to strengthen the exchange of valve manufacturing industry in Europe, has organized more than 10 domestic enterprises had visited Europe valve, learned a lot of valuable experience in foreign counterparts, while compared with foreign valve industry, also saw our own deficiencies.
Processing technology gap
In the welding process, the German company to meet the nuclear-KSB valve sealing material against radiation, has been widely carried out using a special solder powder cobalt welding; French Velan Valve Company will preheating before welding, automatic welding, weld treatment in same equipment or a complete production line processing, whether before welding, welding, after welding, handling, temperature control can be achieved, ensure the welding quality.
While domestic technology behind the valve welded, some welding method also uses the old, low level of technology welder, welding materials are also common materials, reach special valve design requirements. Many enterprises engaged in production and sales all day, with little improvement in the technique on studying.
In forging use of new technology, the German company KSB valve material with high temperature alloy steel F91, F22 based, and high pressure valves Youyi forgings mainly to ensure product reliability and economy. Of the large volume following valve 600Lb using forging and welding, the valve is not caused by casting porosity, and many other defects, and significantly reduce material waste free forging, economy greatly improved.
While the domestic industry, mostly in the blanks valve castings and more, forging rarely used in the following high pressure valve 600Lb forging better described as rare. Many enterprises in this regard in order to reduce costs, mostly using steel casting, low pressure cast iron pieces of more material, low cost, simple processing.