Talking about several major problems of high-strength fastener products


With the development and progress, the quality of its industrial demand is getting higher and higher, so the requirements for fasteners are also increasing. High-strength fasteners can meet everyone's needs. At present, the development prospects of high-strength fasteners are good. However, there are still some problems with domestic high-strength fasteners. According to our understanding, there are mainly the following major problems.

1. The guaranteed load and wedge load are unqualified. Guaranteed load and wedge load are the key items for assessing the mechanical performance of products under tensile loads. , especially important for high-strength fasteners. Guaranteed load is to assess the plastic deformation resistance of the product under the specified tensile load. If the index does not meet the requirements, plastic deformation may occur due to the pre-tightening force and working load, thereby reducing the pre-tightening force and making the connection loose. . The wedge load test is to assess the tensile strength of the bolt product and the joint strength of the head rod. This index is unqualified. Under the action of a large working load, especially the impact load or the support surface is subjected to partial load, fracture or Turning around, causing connection failure, and even safety accidents.

2. The hardness is unqualified. Hardness is also an important indicator for assessing the mechanical properties of fasteners. The materials used for products of each performance level are different. The mechanical performance level is an important basis for the selection of fasteners. During installation and use, the working load should be determined according to the performance level And installation torque, for specific materials, the hardness should be controlled at a reasonable level, high hardness may reduce the fatigue resistance of the product, some companies control the hardness at a higher level in order to improve the strength of the product, causing some products to exceed the standard.

3. The decarburized layer exceeds the standard. The decarburization layer is also a category A project. Due to decarburization, the surface hardness and strength of the parts are greatly reduced, which seriously affects the surface contact strength and fatigue life of the fastener, especially the damage to the threaded part is more prominent. The main causes of decarbonization are decarbonization of raw materials, decarbonization in the process of material transformation and decarbonization in the process of heat treatment of products.

4. The size is out of tolerance. Fasteners are general-purpose parts with high requirements for interchangeability. Dimensional deviation will directly affect their interchangeability, and even affect the connection strength, anti-loosening performance or service life. The main reason for the unqualified size is that the process is not properly controlled. In order to save materials, some dimensions are controlled near the lower limit. During the production process, the equipment is not adjusted in time, and the tools and molds that are out of tolerance are used. The second is that the inspection is not effective, the process inspection and the factory inspection It is not strict, so that some unqualified batches pass the customs; the third is that the measuring tools in use cannot be regularly verified, and even the gauges that exceed the wear limit are used.

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The fastener industry ushers in new opportunities for development and demand

The growth rate of demand for fasteners in my country is 5%-10%. In 2008, the demand for fasteners was 3.13 million tons, an increase of 9.5% year-on-year. Among them, the automobile industry is the largest user, followed by the maintenance industry market and construction industry, and then electronics industry. Recently, in order to stimulate domestic demand, the state has issued a number of policies to support the manufacturing industry. In the government's 4 trillion yuan investment plan, the focus is on the construction of railways, highways, airports, power grids, and affordable housing infrastructure. The most direct beneficiaries are equipment. Manufacturing industry, which will greatly stimulate the demand for fasteners. In particular, the demand for high-strength fasteners with a specification of 1630mm ≥ 10.9 will increase sharply. In addition, the development of the aviation industry has also played a strong supporting role in the demand for fasteners. For example, Boeing plans to add 3,400 new aircraft in the next 20 years. This data will bring new development and demand opportunities for the fastener industry.


2021 Global and Chinese Fastener Industry Market Whole Industry Chain Development Prospect Forecast and Demand Scale Analysis

Fasteners are the most widely used basic components in industry today, and are known as "industrial rice". Fasteners are characterized by a wide variety of specifications, different performances and uses, a high degree of standardization, serialization, and generalization, and a wide range of applications, involving many sectors of the national economy. They are widely used in various machinery, equipment, vehicles, ships, Railways, bridges, buildings, structures, tools, instruments, chemicals, instruments and other products. The prosperity of the above-mentioned main application industries is high, and the demand for fasteners is large, which will further stimulate the expansion of the production capacity of fastener enterprises. The technological progress and industrial upgrading of the main application industries will further increase the requirements for the performance and quality of fasteners. Promote the advancement of the technical level of the fastener industry and promote the improvement of the quality of fastener products; the development of new application fields will expand the market demand for fasteners and promote the diversification of fastener products. In recent years, the entire fastener industry in my country has basically maintained a steady and steady growth. Generally speaking, due to the slowdown in global economic growth and the increasing downward pressure on the domestic economy, the growth in downstream demand for fasteners has slowed down, especially The low-end production capacity of domestic fasteners is seriously overcapacitated, but the supply of high-end products is insufficient, and the fastener industry has shifted from high-speed growth to high-quality growth.


Standard parts can be used for those aspects

Can standard parts be used in that way? In fact, standard parts are a type of mechanical parts that are used for fastening connections and are widely used. All kinds of fasteners can be seen on various machinery, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments, meters and supplies. It is characterized by a wide variety, different performances and uses, and the degree of standardization, serialization, and generalization is also extremely high. Therefore, some people also refer to a class of fasteners with existing national standards as standard fasteners, or simply as standard parts. Fasteners are the most widely used basic mechanical parts. With my country's accession to the WTO in 2001, it has entered the ranks of international trade powers. Construction fastener T-bolt


Talking about several major problems of high-strength fastener products

With the development and progress, the quality of its industrial demand is getting higher and higher, so the requirements for fasteners are also increasing. High-strength fasteners can meet everyone's needs. At present, the development prospects of high-strength fasteners are good. However, there are still some problems with domestic high-strength fasteners. According to our understanding, there are mainly the following major problems.


Hexagon bolts Hexagon nuts Commonly used fastener standards Knowledge

At present, the most commonly used standards in our daily business are as follows:


Common sense of high strength bolts

High-strength bolts are high-strength bolts and belong to a standard part. In general, high-strength bolts can withstand a larger load than ordinary bolts of the same specification.