The characteristics and applications of fasteners made of different materials

Fasteners are a type of component widely used in machinery, construction, automobiles and other fields. Their function is to firmly connect two or more components together.

Common fasteners include bolts, nuts, screws, studs, washers and rivets, etc. Bolts are usually used to connect two or more components; The nut is used in conjunction with the bolt and is fastened by rotation. A screw, on the other hand, is a type of fastener without threads, which is fixed by its own taper or slope. Rivets are used for permanent connections. Once installed, they are very difficult to remove.

Fasteners can be classified into the following three categories based on their different materials:

(1) Carbon steel fasteners

1 Characteristics

High strength: After proper heat treatment, carbon steel can achieve high strength, capable of withstanding certain tensile and compressive forces, and meeting the connection requirements of many general industrial scenarios.

Good processing performance: Easy to cut, forge and cold heading, which enables carbon steel fasteners to be conveniently formed into various shapes and specifications during the manufacturing process, resulting in high production efficiency.

Lower cost: Compared with stainless steel and alloy steel, the raw material cost of carbon steel is lower, which gives carbon steel fasteners a significant price advantage and they are widely used in projects that are sensitive to cost.

Limited corrosion resistance: The main drawback of carbon steel is its relatively poor corrosion resistance. It is prone to rust in a humid and corrosive medium environment and requires appropriate surface treatment (such as galvanizing, painting, etc.) to enhance its corrosion resistance.

2 Uses

Construction industry: It is used for the connection of building structures, such as the connection of beams and columns in steel structure buildings, as well as the construction of some temporary building facilities. In these application scenarios, carbon steel fasteners, after surface treatment, can provide sufficient strength to ensure the stability of building structures.

General mechanical manufacturing: It is widely used in the connection of components of ordinary machinery, agricultural machinery, transportation equipment, etc. For instance, at some connection parts of a car chassis, the use of carbon steel bolts and nuts can meet the connection requirements under normal driving conditions.

(2) Stainless steel fasteners

1 Characteristics

Outstanding corrosion resistance: Stainless steel contains alloying elements such as chromium and nickel, which endows it with excellent corrosion resistance. It can be used for a long time in harsh environments such as dampness, acidity, and alkalinity without rusting. This is the most notable feature of stainless steel fasteners.

Good aesthetic appeal: Stainless steel itself has a bright surface and can be used in some occasions with appearance requirements without additional surface treatment, such as food processing equipment, medical devices, high-end architectural decoration, etc.

Strength and toughness: Different types of stainless steel have different strengths and toughness. Generally speaking, austenitic stainless steel has better toughness, and martensitic stainless steel can achieve higher strength after heat treatment, which can meet the mechanical property requirements under various working conditions.

High-temperature performance: Some stainless steels can still maintain good mechanical properties and corrosion resistance in high-temperature environments, making them suitable for some high-temperature working conditions, such as the connecting parts of chemical reaction vessels.

2 Uses

Food and beverage industry: It is used for the assembly of food processing equipment, packaging machinery, etc., to ensure hygiene and safety during the food production process and prevent food contamination due to rusting of fasteners.

Medical equipment: It is widely used in the manufacturing and assembly of medical devices, such as surgical instruments, medical beds, diagnostic equipment, etc. Its corrosion resistance and biocompatibility ensure the quality and safety of medical equipment.

Marine engineering and chemical engineering: It plays a significant role in the connection of offshore platforms, shipbuilding, and chemical equipment. As these environments usually have high humidity, high salt content or corrosive chemicals, stainless steel fasteners can effectively resist corrosion and ensure the long-term stable operation of the equipment.

(3) Alloy steel fasteners

1 Characteristics

High strength and wear resistance: Alloy steel is made by adding alloying elements (such as chromium, molybdenum, vanadium, etc.) to carbon steel. The addition of these elements significantly enhances the strength, hardness and wear resistance of fasteners. It can withstand extremely high loads and friction, and is suitable for harsh working conditions such as heavy loads and high-speed operation.

Heat resistance and low-temperature resistance: Some alloy steels have excellent heat resistance and low-temperature resistance. It can maintain high strength and stability in high-temperature environments. Even in low-temperature environments, there will be no embrittlement phenomenon, ensuring reliable connection under extreme temperature conditions.

Good fatigue resistance: Alloy steel fasteners have excellent fatigue resistance under the cyclic stress of repeated loading and unloading, which can effectively extend their service life. This is very important for some equipment that needs to withstand dynamic loads for a long time, such as engines, compressors, etc.

The processing difficulty is relatively high: Due to the high content of alloying elements in alloy steel, its processing performance is relatively poor. During the manufacturing process, special processing techniques (such as high-temperature forging, precision cutting, etc.) need to be adopted, and the requirements for tools and equipment are also relatively high, resulting in relatively high production costs.

2 Uses

Aerospace field: It is used in the connection of key parts such as aircraft engines, landing gears, and fuselage structures. These parts need to withstand huge flight loads, high temperatures, vibrations and other complex working conditions. Alloy steel fasteners can provide reliable connections to ensure flight safety.

High-end mechanical manufacturing: In the manufacturing of high-end equipment such as heavy machinery, precision machine tools, and high-speed trains, alloy steel fasteners are used to connect key components, such as the connecting rods of large presses and the connection of shafts and bearings of high-speed motors, meeting the requirements of high precision and high reliability of the equipment.

Energy industry: It plays a role in the connection of energy-related equipment such as oil extraction equipment, power generation units, and nuclear energy facilities. For example, in the connection of wellhead devices on oil drilling platforms, alloy steel bolts can withstand the effects of high pressure, high temperature and corrosive media.