1, the type and use of fasteners

The size of fasteners is generally metric threads, which are divided into coarse ribbed and fine ribbed according to the diameter and pitch. Because fasteners have a variety of different sizes, accuracy, strength and production materials, these elements combine to make the types of fasteners hundreds of thousands, millions of many.

Roughly speaking, fasteners can be divided into positive rib products of bolts and negative rib products of nuts. According to the shape of the rotating part of the head of the fastener, there are a cross slot head, a single slot of the head, and a hexagonal head. In addition, for different use environments and purposes, fasteners have additional characteristics, so the classification of fasteners is quite complex.

Chenzheng fastener analysis of the development trend of fastener technology

On the strength of screws and bolts, the first number is 1/100 of the nominal tensile strength of MPa as a unit, and the second number is 10 times the ratio of the nominal yield point to the nominal strength, such as "10.9", indicating that the nominal tensile strength is 1000MPa and the 0.2% yield strength is 900MPa of the bolt.

The strength of the nut is expressed by the strength level number of the high strength bolt used in combination with it. The strength of stainless steel fasteners is expressed by a combination of steel grades and tensile strength level numbers, such as "A2-50".

These expressions are international unified fastener strength expression methods. Fasteners are better products for standardization in industrial products, and detailed regulations can be seen in ISO standards.

Fastener materials are carbon steel, alloy steel, stainless steel and other steel materials and copper, aluminum and other non-steel materials, only ordinary carbon steel, alloy steel and stainless steel fasteners are very many varieties.

2. Technical development of fasteners

Fastener high strength: Improving the strength of fasteners can reduce the number of fasteners used, reduce the diameter and reduce the weight. However, it is necessary to solve the problem of delayed fracture and fatigue fracture of bolts with tensile strength of 1200MPa and yield ratio of more than 90%. Therefore, the development of steel for high-strength bolts is important, and the development of high-strength bolt manufacturing technology should also be carried out at the same time.

Small and lightweight fasteners: under the premise of no loss of fastening performance, small and lightweight fasteners are developed. Therefore, the new materials and shapes of fasteners are studied, and the processing methods of difficult materials are also developed.

Utilization of new materials: Fastener materials for aircraft and medical equipment and improved fasteners were developed, and new materials such as Ti alloy and Mg alloy were developed.

Fastening technology and anti-relaxation technology: In order to make fasteners firmly fastened on the parts and prevent accidents due to relaxation, fastening technology and anti-relaxation technology are studied. Due to the lack of careful installation of fasteners resulting in a decline in fastness leading to major accidents, so it cannot be taken lightly.

It should be realized that the easy installation and safe use of fasteners are two completely different concepts, and the key to play the fastening role of fasteners is the correct installation operation, so the development of construction methods to improve the fastening design and strengthen the fastening operation cannot be stopped.

Chenzheng Fastener is a leading comprehensive industrial fastener manufacturing Co., LTD., mainly engaged in: anchor bolts, stud bolts. U-shaped bolts. Special-shaped parts, building accessories, bolts, nuts, screws, flat washers, expansion bolts and other products production and processing company, has a complete and scientific quality management system. And a series of fastener products such as hardware tools and have been sold all over the country, praised by the majority of customers, products in short supply.