In the past 15 years, nodular cast iron piston rings have been widely used in various engines such as agricultural machinery, automobiles (including cars and mini cars) and motorcycles. There are many manufacturers producing nodular cast iron piston rings, and the output is also large. For example, the output of finished nodular cast iron rings for automotive diesel engines of Yizheng double ring piston ring Co., Ltd. has reached 150 million pieces in 2003, and will continue to increase significantly in 2004.
There are many casting methods for producing nodular cast iron piston rings in China, but it mainly refers to the technology of the same industry in developed countries such as Germany and Japan. For more than ten years, we have successively inspected Germany’s Goetze company, Japan’s Rik E N company, Japan’s piston ring company (n PR), Russia’s Volga automobile factory, and learned about South Korea’s YpR, India’s Goetz and other piston ring companies. The ductile iron rings of these companies mainly include double piece, four piece Different processes of nodular cast iron piston rings such as short cylinder and single piece are briefly introduced as follows for reference.
- From the main foreign advanced countries such as Germany, Japan, Russia and South Korea, there are three main casting production processes of nodular cast iron piston rings abroad: Double piece casting, four piece casting and barrel casting.
- For the production of ductile iron rings in China, Japan, South Korea, India and other countries, the early casting process of double piece ductile iron piston rings of German Gertz company has been introduced. Double piece nodular cast iron piston ring casting does not require high molding equipment and slicing machine tools. It is the simplest and convenient nodular cast iron piston ring casting process. At present, it is applied in many countries in the world.
- The four piece nodular cast iron piston ring casting process of Gertz company is based on the casting of its two-piece nodular cast iron piston ring, increases the height of the ring mold, and makes full use of the original full-automatic molding machine, steel plate square sand box and automatic production line. This process can greatly improve the production efficiency and blank output of nodular cast iron piston ring casting, and greatly save the cleaning of molding sand, blank and return material. The four piece process is not only suitable for ductile iron rings, but also for F14, KL, K4 and other materials. However, the problem of efficient grinding wheel slicing machine tool must be solved first. Can be put into mass production.
- The casting process of cylinder nodular cast iron piston ring of RIKEN, NPR and Volga automobile factory in Russia uses Japan Guangyang automatic production line and vertical parting box free molding process, which has high production efficiency and high requirements for molding sand. This process is also to manufacture high-efficiency slicing machine tools to solve the slicing problem. Compared with the two slicing machines in Russia and Japan, the structure of Russia is simpler and the slicing efficiency is higher, which is worthy of learning from the same industry in China.
- At present, the domestic nodular cast iron ring is mainly the casting process of double piece nodular cast iron piston ring, which was previously introduced from German gerz company. In addition, there are a small number of single chip and lost foam casting processes, which are only applicable to micro cars and motorcycle rings. They are not very adaptable to varieties, and there are some obvious shortcomings. At present, it seems that the promotion value is not high.
- From the perspective of development, in order to reduce production personnel, improve production efficiency and reduce production cost, the four piece process should be developed for the casting process of nodular cast iron piston ring in the future, so as to make full use of the existing semi-automatic molding machine and production line. The newly-built casting workshop can go to the automatic vertical parting box less molding production line of Guangyang or Desa company in Japan, so as to further improve the production efficiency and reduce the casting scrap rate of nodular cast iron piston ring.
- Through technical exchange and visit and study, we have a clear understanding of the casting process of four ellipses and cylinder ellipses. In the future, when the conditions are ripe, we can further test and verify the material composition, metallographic structure and mechanical properties of the simple ring.
- The slicing machine for four piece and cylinder ductile iron ring is a very important issue, which is related to whether these two advanced processes can be popularized and applied. Qualified piston ring manufacturers can trial produce, jointly develop with special machine manufacturers, or introduce foreign slicing machine tools for re imitation, so as to lay a foundation for the popularization and application of foreign advanced and mature nodular cast iron piston ring casting technology.