Jiangxin Time: The "invisible shield" of fasteners: the role and application scenarios of different surface coatings

Fastener surface coating

In the fastener industry, products such as bolts and nuts not only bear the important task of mechanical connection, but their surface treatment process is also a key factor in determining their durability, corrosion resistance and aesthetics. The surface coating is like an "invisible shield", protecting fasteners from environmental influences and extending their service life. Different coating technologies are suitable for different application scenarios. Today, we will introduce four common surface coatings: hot-dip galvanizing, Dacromet, blackening, and nickel plating, and explore their roles and application areas in fasteners.

Hot dip galvanizing

Principle and characteristics:
Hot-dip galvanizing is to immerse the fasteners in molten zinc liquid to form a zinc layer on the surface. This zinc layer can not only protect the fasteners from oxidation and corrosion, but also provide a certain electrochemical protection when the zinc layer is damaged to prevent further oxidation of the substrate.

Advantages:

It has excellent corrosion resistance, especially suitable for outdoor environments.

The coating is thicker and can provide long-term protection for fasteners.

Application scenarios:

Hot-dip galvanized fasteners are widely used in large-scale structural projects such as buildings, bridges, wind power equipment, and communication towers. They are particularly suitable for occasions exposed to harsh environments such as the ocean, humidity, and acid rain. Due to their strong anti-corrosion ability, hot-dip galvanized fasteners are favored in outdoor equipment and infrastructure construction.

Dacromet

Principle and characteristics:
Dacromet is a coating based on zinc and aluminum flakes, which is usually applied to the surface of fasteners by spraying or dipping, and cured at high temperature to form a film. It is thinner than hot-dip galvanizing, but has extremely high corrosion resistance and is not prone to hydrogen embrittlement.

Advantages:

Excellent corrosion resistance and long corrosion resistance.

Suitable for high-strength bolts, without hydrogen embrittlement affecting their strength.

The coating is thin and does not affect the tolerance size of the bolts.

Application scenarios:

Dacromet coated fasteners are commonly used in industries such as automobiles, aerospace, and rail transportation, which have extremely high strength requirements for fasteners and need to ensure their durability in highly corrosive environments. For example, fasteners in automobile engine compartments and chassis components, Dacromet coatings can effectively prevent corrosion and ensure long-term stable use of fasteners.

Blackened

Principle and characteristics:
Blackening treatment is to form a black oxide film on the surface of fasteners through an oxidation process. This oxide film can prevent rust to a certain extent and give the fasteners a beautiful appearance. Although the anti-corrosion performance of blackening treatment is not as good as that of galvanizing and other processes, it is suitable for occasions where anti-corrosion requirements are not high.

Advantages:

Low cost, suitable for mass production.

Beautiful appearance, can add a black matte effect to fasteners.

Does not change the size of the fasteners and can be used for precision parts.

Application scenarios:

Blackening treatment is mostly used in indoor mechanical equipment, tools, instruments, molds and industrial equipment, etc., mainly used in occasions where anti-rust requirements are not high but appearance requirements are high. Blackening fasteners are often used in scenes that require beautiful and consistent appearance, and are suitable for indoor use, such as home appliance assembly or structural parts in industrial equipment.

Nickel Plating

Principle and characteristics:
Nickel plating is to deposit a layer of nickel metal on the surface of fasteners through electroplating process. The nickel layer not only provides good corrosion resistance, but also enhances the hardness and wear resistance of fasteners, while increasing the brightness of the surface, making the fasteners more beautiful in appearance.

Advantages:

Excellent corrosion resistance, especially in weak acid, weak alkali and other environments.

Increased surface hardness and wear resistance.

The bright surface improves the decorative effect of fasteners.

Application scenarios:

Nickel-plated fasteners are often used in electronic products, home appliances, decorative parts, and industrial applications that require good appearance and corrosion resistance. For example, precision instruments, consumer electronics, home decoration and other fields that have high requirements for the appearance and corrosion resistance of fasteners.

Choosing the right coating is crucial

In the application of fasteners, different use environments and requirements determine what kind of surface coating is needed. By understanding the characteristics and application scenarios of various coatings, choosing the right surface treatment can effectively extend the service life of fasteners and ensure the safety and durability of equipment.