A Guide to the Selection of Non-Standard Fasteners

In modern manufacturing and engineering fields, fasteners are indispensable basic components. In addition to the standard fasteners we are familiar with, the use of non-standard fasteners is also becoming increasingly widespread. Non-standard fasteners refer to fasteners that do not meet international or national standards. Due to their customized nature, non-standard fasteners can meet the needs of various special working conditions and environments.

Material Selection for Non-Standard Fasteners

The choice of material is one of the key factors affecting the performance of non-standard fasteners. Different materials perform differently in terms of tensile strength, corrosion resistance, abrasion resistance, and so on. According to actual application needs, the following materials are commonly used in the manufacturing of non-standard fasteners.

Carbon Steel

• Characteristics: Carbon steel fasteners have good mechanical properties and high tensile strength. They are usually divided into low carbon steel, medium carbon steel, and high carbon steel based on carbon content, with common strength grades being 4.8 and 8.8. Carbon steel fasteners are suitable for general mechanical structures but are prone to rust in humid or corrosive environments, thus requiring surface treatments (such as galvanizing).

• Application Scenarios: Suitable for general machinery equipment, industrial installations, and other applications that require high strength but do not have special corrosion resistance requirements.

Stainless Steel

• Characteristics: Stainless steel fasteners are outstanding in corrosion resistance and oxidation resistance, performing well in humid, acidic, and alkaline environments. Common stainless steel materials include 304, 316, and 316L. Among these, 316 and 316L have stronger corrosion resistance due to the presence of molybdenum.

• Application Scenarios: Used in the shipping, chemical equipment, food processing, and other industries, suitable for high humidity, high salt, or chemically corrosive environments.

Alloy Steel

• Characteristics: Alloy steel fasteners, by adding elements such as manganese, silicon, chromium, and molybdenum, significantly improve the material's strength and hardness, enhance wear resistance, and corrosion resistance. Commonly used in situations requiring high-strength loads and high-temperature conditions.

• Application Scenarios: Aerospace, automotive manufacturing, wind power equipment, and other industries. Suitable for high temperature, high-pressure, or impact load conditions.

Copper and Copper Alloys

• Characteristics: Copper fasteners have excellent electrical conductivity, thermal conductivity, corrosion resistance, and good plasticity. Because they do not react with water and most chemicals, they are often used in electronic and electrical equipment.

• Application Scenarios: Power equipment, electronic components, suitable for applications requiring electrical conductivity or corrosion resistance.

Titanium and Titanium Alloys

• Characteristics: Titanium fasteners have a very high strength-to-weight ratio and excellent corrosion resistance and high-temperature performance. Due to the lightweight and high-strength characteristics of titanium materials, they are widely used in aerospace and high-end manufacturing industries.

• Application Scenarios: Aerospace, medical devices, chemical industries, suitable for extreme environments or applications with strict weight requirements.

Specification Selection for Non-Standard Fasteners

In the selection process of non-standard fasteners, determining the specifications and dimensions is crucial. The specifications not only affect the fastening method but also determine its load-bearing capacity and service life. Common specifications include thread diameter, screw length, and bolt head shape.

Thread Diameter

Thread diameter is one of the most important parameters of fasteners, directly affecting their load-bearing capacity. The appropriate thread diameter is chosen based on the required strength of the fasteners. Generally, the larger the diameter, the stronger the load-bearing capacity, but it is also necessary to consider the installation space and connection needs of the equipment.

Screw Length

Screw length determines the installation depth of the fasteners. In some special occasions, screws of different lengths need to be customized according to actual conditions to ensure the firmness of the connection. Especially in heavy mechanical structures, improper length can lead to loose connections, affecting equipment operation.

Head Shape

Non-standard fasteners have various head shapes, such as hexagon head, cylindrical head, countersunk head, and so on. The choice of head shape not only affects the appearance of the fasteners but also determines their installation method and fastening effect.

• Hexagon Head: The most common head shape, installed using a wrench, suitable for most mechanical equipment.

• Cylindrical Head: More aesthetically pleasing, suitable for occasions requiring smooth surfaces.

• Countersunk Head: The head is embedded in the material, flush with the surface, suitable for installations requiring a flat surface.

Non-standard fasteners are designed according to the special needs of customers, with specific size, shape, materials, or performance requirements. These fasteners are widely used in special machinery equipment, aerospace, shipping, rail transportation, and other industries, meeting the requirements of strength, corrosion resistance, high-temperature resistance, and more under different working conditions.