Top 4 Surface Treatments for Metal Parts

Last Updated on October 6, 2023 by assistant

After machining, the metal parts still need more perfection. For example, the surface of the metal parts has tool scratches, roughness, burrs, or is too easy to corrode. Any of them will undoubtedly affect the final performance, lifespan, and aesthetics of the metal part. They may ultimately result in wasted time and money.

Different types of surface treatments can correspondingly solve these problems. Further knowing their properties and effects will help you choose the most suitable finish. In this article, we will introduce the top 4 popular surface finishes for metal parts to help you get a basic understanding of them.

Bead Blasting
When do you need to use bead blasting? After CNC metal machining, some tool marks are inevitably left on the surface of the metal parts. Bead blasting can effectively cover up these imperfections. So what is the process of sandblasting?

Bead Blasting Process

If we use semi-automatic bead blasting machines, craftsmen just need to hold the work-pieces manually to be sprayed in the machine. The sandblaster will be spray beaded media through a high-pressure tool to the surface of the metal. During this process, what craftsmen need to do is keep adjusting the direction of the part according to the situation until it is completed.

After bead blasting, the surface of metal parts becomes smoother and cleaner. At the same time, it has been a preferred preparation for other surface finishing techniques. It helps the metal to be completely oxidized and powder coated by clearing the tool marks. The surface of the parts will also be attached with a special texture. This is why many people tend to opt for bead blasting in their metal fabrication projects.

Bead Blasting Parts

The length of the product lifespan of the metal parts largely depends on their wear resistance and corrosion resistance. Among a variety of surface treatments, anodizing is commonly applied to increase the corrosion resistance of aluminum parts.

By adding an oxide film to the parts, the machined aluminum parts are of a stronger oxide film. It not only increases the thickness of the surface of the aluminum parts but also adds an aesthetic appeal.

Anodizing Metal Parts

There are three categories for anodizing: anodizing type I, anodizing type II, and anodizing III. Anodizing type I is your best option if you just want to make aluminum machined parts of a decorative surface. Anodizing types I and II are suitable for the components with higher requirements for corrosion resistance.



Powder Coating
Why do you need powder coating for metal parts? What is the process of powder coating? It is a popular surface finish, which can be used on a wide variety of metals, including aluminum and brass. And steel is the most common one by powder coating. Its process is characterized by low toxicity and flammability. This is because the raw material it uses is a mixture of ground pigments and resin particles. And you can choose any pigment to determine the color of the powder coating for metal parts.

Powder Coating for Metal Parts

Before powder coating, the first step we need to do is – remove the oil and rough scratches from the steel parts by sandblasting. It is a process commonly used to remove scratches on metal parts. After that, it can achieve its best performance. After being sprayed onto the machined metal part and melted, a smooth and hard film is formed on the steel metal part.

What are the benefits of powder coating?

Powder Coated Metal Parts

  • Increase the durability and corrosion resistance. Parts after powder coating can effectively prevent scratches and impact damage. It also makes the metal parts have stronger corrosion resistance in a wet environment.
  • Less cost and more environmentally friendly. Compared to other finishes, powder coating requires less labor and shorter turnaround times. In addition, it does not evaporate harmful substances during the curing. That’s why it has little impact on the environment.
  • Smooth and flawless. After sandblasting, the bumps or streaks of the metal parts will be covered and then powder coating can achieve its best results. Alongside that, if you need glossy and matte textures, powder coating can do it for you.


If you need metal parts with a good surface finish, polishing will be your best choice. By using a variety of polishing tools, it can reduce the roughness of metal parts with better surface cleanliness. Common polishing processes include mechanical, chemical, and electrolytic polishing.

Polishing for Metal Parts