Material Selection Principles and Type Analysis of Stainless Steel for Fasteners

The selection of stainless steel fasteners

Stainless steel is an alloy material, composed of iron and chromium, which has excellent corrosion resistance, high temperature oxidation resistance and high strength. Stainless steel fasteners are widely used in various fields due to their versatility and advanced performance. In this paper, we will discuss the principles and types of stainless steel fasteners.

First, when selecting the stainless steel fasteners, it is necessary to select according to the structural strength, corrosion resistance, thermal resistance and other conditions required by the specific application. In terms of structural strength, the strength of stainless steel fasteners increases with the increase of carbon content, and the strength of stainless steel fasteners is improved by strengthening and tempering. The stainless steel fastener materials are divided into martensitic stainless steel, austenitic stainless steel, ferritic stainless steel and duplex stainless steel. According to the corrosive environment, martensitic stainless steel is used in environments containing medium and high concentrations of halides, and austenitic stainless steel is used in environments containing low concentrations of halides and acetic acid. The thermal resistance of stainless steel fasteners is improved by increasing the chromium content, but the cost is also increased.

Secondly, the selection of stainless steel fasteners should be based on the form and specifications of the fasteners, such as screws, rivets and gaskets. In terms of specifications, what type of fastener should be chosen depends on the load, environment and application, etc. For example, screws are widely used in applications involving light shock and vibration, but high-strength nuts and bolts are more suitable for applications requiring higher fastening strength. Rivets are widely used for permanent applications, and gaskets are suitable for dynamic applications, such as high temperature and pressure, because of their relatively low cost.

Thirdly, after selecting the fastener material, it is also necessary to consider the surface treatment. Based on different applications, different surface treatments can be selected, such as hot dip galvanized, electroplated, etc. Hot dip galvanizing is a traditional process that applies a zinc coating on the surface of ferrous metals to improve its corrosion resistance, and the quality of hot dip galvanizing is relatively stable. Electroplating is a process of metal deposition, which is mainly used to make the surface of metal decorative, can increase the wear resistance and improve the lubricity of the metal product.

Finally, when selecting stainless steel fasteners, the type of thread also needs to be taken into consideration. The most commonly used thread forms are National Coarse Thread (NC), National Fine Thread (NF) and National Special Thread (NS). The cross-section forms of each thread are different and their winding heights are also different, so selection should be based on the threaded connection size and operating environment.

In short, when selecting stainless steel fasteners, it is necessary to select according to the specific application, such as the structural strength, corrosion resistance and other conditions, as well as the form and specifications, surface treatment and type of thread. It is very important to choose the right stainless steel fasteners for specific applications.

In the selection of stainless steel fasteners, attention must be paid to the specific choice. This will ensure that the fasteners have good corrosion resistance and maintain the structural strength of the product.

The first principle of selection is to choose fasteners made of stainless steel. The most common are austenitic stainless steels such as 304 (1.4301) and 316 (1.4401). As a general rule, its corrosion resistance increases as the chromium and nickel content of the material increases.

Next, consider the type of fastener. Depending on their application, the selection of fasteners may include the following: bolts, screws, nuts, washers, rivets, pins, anchors, and studs. Each of these fastener types must have good corrosion resistance to ensure the overall integrity of the product.

Finally, consider the shape and size of the fastener. Generally speaking, fastener shapes can be divided into round and non-round shapes. The size should be selected according to standards such as ISO (International Standardization Organization) and ASQ (American Society for Quality) standards.

Nowadays, stainless steel fasteners have become increasingly popular, thanks to their superior corrosion resistance, durability and versatility. By selecting fasteners of the most appropriate type, shape and size, designers can ensure the performance of their products.