Analysis of the gap between domestic valve enterprises and foreign valve enterprises
Although China's valve industry has developed rapidly in recent years, the overall level of the industry is still low, low technical content of products, many key valves with high parameters are still dependent on imports. Some experts estimate that the valve level of China and foreign advanced countries to lag behind 10~20 years. Not long ago, the Chinese valve industry to strengthen the exchange with the European valve manufacturing industry, has organized more than 10 domestic valve enterprise managers to visit Europe, learned a lot of foreign counterparts valuable experience, and compared with the foreign valve industry, also saw our own shortcomings.
The difference in processing technology
In welding process, KSB company of Germany has widely used special welding powder for cobalt-free welding in order to meet the requirement of radiation resistance of sealing materials of nuclear valves. France welland valve company will be pre - welding preheating, automatic welding, welding after treatment in the same equipment or the same processing line to complete, no matter before welding, welding, welding after treatment, the temperature can achieve automatic control, to ensure the quality of welding.
But the domestic valve welding process is backward, some still use the old welding method, welder technology level is low, the welding material is also common material, can not reach the special valve design requirements. A lot of enterprises are busy with production and marketing all day long, and little research and improvement is made in the process.
In the application of new die forging process, Germany KSB company to produce valve material to high temperature resistant alloy steel F91, F22, and high pressure valve to forging, to ensure the reliability and economy of the product. For gate valves under 600Lb in large batches, die forging is adopted and welding is carried out. The valve does not have many defects such as porosity and porosity caused by casting, which greatly reduces the waste of free forging materials and greatly improves the economic efficiency.
And the domestic industry valve blank parts are mostly cast parts, using die forging is very few, under 600Lb high pressure valve die forging is even more rare. In this respect, in order to reduce the cost of many enterprises, most of the use of cast steel, low pressure cast iron, low material cost, processing technology is simple.
Gaps in quality management and equipment
France Bernard electric device company in 2005 sales of 300 million yuan, exports accounted for 70% of the sales, established a global sales network, China's metallurgy, papermaking, water treatment and oil and gas pipeline valves a large number of the company's denso products. They are the world's second largest supplier of nuclear power, with more than 70 plants in France using their products. Their management is very good, the company's parts processing record sheet with the parts flow, the production site is neat, neat, two assembly lines in order to work. Their screw processing adopts rolling method, high efficiency, high surface finish of the parts. The parts after processing are cleaned in a timely manner, and the station appliances are applied properly, such as a plastic bag on each axle, which is very simple, but very practical, and avoids the collision and scratch between the parts. Parts of the coating method and domestic about the same, but because of the blank itself smooth and smooth and the quality of the paint, paint after the product, the appearance and quality is quite good.
Compared with that, there are still many defects in quality management in China. First of all, it is more or less ignored in the process. Many enterprises clearly have a quality assurance system, but there is no room for them to use it in the actual work. Secondly, it is also careless in the assembly process. No wonder some valves appear to run, run, drop, leakage when installed.
Another example is that many domestic enterprises have backward production equipment, which is still at the level of the 1970s to the 1980s. Some equipment has already passed its service life and is still operating at full capacity. How can the quality of product processing be guaranteed? Some are limited to capital, also in succession to acquire numerical control and processing center, but the formation of numerical control processing enterprises so far in the industry is not much, only 20% or so.
Gaps in process management
The equipment layout of France weilan company is carried out according to the product process route, so as to achieve the processing process route Z is short, so that the operator can complete the workpiece processing within the small action scope of Z.
They used a large number of machining center or even five axis linkage of the flexible machining center, CNC turning and milling machine tools and CNC CNC machine tools, computer aided manufacturing into a line, the product in the equipment a clamping, a programming. Programming work can even be remotely operated in the office, so as to simplify the machining process, engineers and technicians as long as the program is good, choose the right tool, can ensure the processing requirements of the product, and make the product high quality and high efficiency.