Domestic textile machinery: How can a good textile machine be made without good steel?

As the main material of main manufacturing and production machinery, steel quality determines the mechanical performance. Today, China's steel output has long been the first in the world, but with the increase of production capacity, the metallurgical technology level has not been significantly improved. China's metallurgical technology, whether in terms of technology and new product development, or in terms of informatization and refinement, still has a certain distance compared with similar foreign enterprises.
Backward metallurgical technology hinders mechanical performance
Zhou Yongtai, executive director and senior engineer of China Die&Mold Industry Association, said frankly in an interview: "The performance, quality and variety of metal materials often affect the quality, service life and cost of mechanical products. Compared with foreign steel products, there is a big gap between domestic steel products and foreign steel products in terms of quality, variety and specification."
Taking the rapier loom as an example, the rapid development of the textile industry has put forward higher and newer requirements on the quantity, quality, variety and performance of mold materials, such as the high standard and high-performance rapier head. Due to the speed requirements of the rapier loom, the rapier head material should have very good impact toughness, and at the same time, it should not affect the quality and life of the rapier head. In the process of smelting metal, it is necessary to grasp the control of residual elements.
However, there is still a certain gap between the varieties, specifications, quality and performance of domestic materials and the international advanced level, which leads to that China imports quite a lot of rapier head materials from abroad every year.
Wang Guoxing, the director of the Textile Machinery Research Institute of the Chinese Academy of Textile Sciences, believes that a piece of equipment, from microelectronic components to the body, frame, etc., contains various components with different strengths and surface states, such as plastic, copper, aluminum, steel, etc. During the production process of any component, all physical properties, appearance quality, etc. must meet the design requirements, which requires that the quality of metal materials must be guaranteed. The textile machinery manufacturing enterprises first require that the metal shall not fail as a whole, that is, the metal shall not crack; Secondly, textile machinery enterprises require that the first part produced has the same physical properties, appearance and dimensional tolerance as the last part, so metal materials should also ensure sufficient strength.
With the rapid development of the textile machinery industry, the production of die castings tends to adopt higher pressure and more automatic die casting machines, which requires that metal materials have excellent red hardness (high temperature yield strength) and ductility (plasticity) at the same time. The current situation is that some metal materials in China are not up to the standard, which makes textile machinery enterprises have to use imported metal materials with higher costs.
Domestic materials have a short service life and are embarrassed to face the market
Facing the new emerging market of metal materials in China, domestic steel enterprises are very embarrassed: domestic metal materials cannot fully meet the needs of domestic machinery industry.
First, the production process of die steel is backward and the steel quality is poor. For example, the internal quality of domestic universal die steel varieties such as h13, d2 and ld can meet the American general standard for die steel astma681, which belongs to the international general level and can basically meet the use needs of general die users at home and abroad. However, the high requirements put forward by users of high standard die steel, such as the control of residual elements such as impact toughness and low carbide content, and the requirements of high quality and long life, cannot be met at present.
The comparison of die technologies at home and abroad shows that the service life of foreign hardened steel dies is 1.6 million to 3 million times, while that of domestic ones is only 0.5 million to 1 million times. The service life of domestic non quenched steel dies is only half of that of foreign ones. In addition, there are few new varieties of domestic die steel. In recent years, some foreign famous die steel manufacturers have developed many new die steel products, such as high strength and toughness die steel, dh13, dh53, flame hardening die steel, powder metallurgy cold work die steel, etc. In contrast, there are fewer new products of high-performance die steel made in China and fewer new varieties of die steel are developed. For example, the plastic die steel, which accounts for 60% of the die steel consumption, has only two steel grades in China's alloy tool steel standards, while the United States has seven steel grades, and has formed a relatively complete steel series. The United States, Japan, France, Switzerland and other countries have formed a series of cold work die steels and hot work die steels. Only hot work die steels have 6 types of finalized universal varieties, which are currently inferior to domestic die steels.
Horizontal combination, a shortcut for domestic textile machinery
The development of high-tech products in China's textile machinery industry requires special metal materials, chemical products, rubber products, electronic, electrical components, hydraulic parts, fasteners and other basic supporting products and parts. At present, domestic supporting parts are insufficient in material, manufacturing precision and quality. However, using international supporting parts has problems such as high price and long cycle, which directly affects the development of textile machine automation technology. Therefore, some professionals suggested that China's textile enterprises could "go global" and horizontally unite, which should be a shortcut for the future development of textile enterprises. If conditions permit, textile machinery enterprises can adopt advanced metallurgical methods and processes, such as furnace refining, electroslag remelting, vacuum treatment, multi-directional forging, precision forging, and precision rolling, to produce high-quality steel with purity, and provide finished and high-quality mold steel products through machining, tempering and other methods.
Textile machinery enterprises should strengthen the innovation and application of surface treatment technology. On the basis of maintaining the original composition and performance of the product, the surface treatment can endow the mold surface with special performance (mainly abrasion resistance, corrosion resistance, etc.), greatly improve the service life of the product, broaden the application range of the product, and can also replace the expensive mold steel with the low-cost mold steel, in order to widely apply various kinds of high-quality surface treatment in textile machinery products.