How many surface treatments could do for stainless steel machining parts?

cnc machining

Worthy Hardware, as an ISO-certified business, we offer quick turnarounds and friendly service to all our clients. We have produced many kinds of precision stainless steel machining parts in the past 25 years. As stainless steel materials have a unique strength, high wear resistance, superior anti-corrosion resistance, and are not easy to rust, and other excellent characteristics, they are widely used in the chemical industry, food machinery, electromechanical industry, environmental protection industry, household appliances industry and home decoration. The stainless steel surface treatments also varied according to different usage scenarios.

Stainless steel precision products can be mirror-polished and brushed, but what about other surface treatments? We hope this article has inspired you to get started on your next CNC machining manufacturing parts!

1. Why do stainless steel machining parts need to be surface treated?

In many circumstances, Stainless Steel material is more susceptible to chemical reaction than normal iron because of its unique composition and surface corrosion protection film. Even when exposed in most cases it does not normally undergo an oxidation process that breaks the bonds between metal molecules resulting in rusting or tarnishing phenomenon.

However under certain conditions such as abrasion damage from scratching against other objects which cause scattering chemicals on its exterior thus leading slowly for progressive environmentally induced ageing-induced erosion (peeling) before any severe structural failure occurs due to patterned lattice expansion caused by environmental factors at different rates depending on their intensity? Because of this, stainless steel machining parts also need to be surface treated.

2. PVD coating (Physical Vapor Deposition)

PVD is a process of accumulating physical matter on the surface by reacting with noble metals. The coating provided long-lasting protection for your stainless steel product, preventing any possible damage from dirty and harmful things like scratches or oil stains. In fact, it's nearly as hard as synthetic diamond - only surpassed in strength by actual diamonds themselves!

3. Bead-blasting (sand blasting)

The sandblasting of stainless steel parts is usually made of glass beads, and the size of sand particles is generally between 30#—280#. The micro-glass beads sandblasting process uses compressed air as the power source to transform the spray metal materials into a high-speed spray beam and spray it on the surface of the stainless steel parts to be treated so that the surface changes.

Due to the impact and cutting action of abrasives on the surface of stainless steel parts, a certain degree of cleanliness and different roughness is obtained, and the mechanical properties of the product are also improved, thus improving the fatigue resistance and corrosion resistance of the parts.d harmful things like scratches or oil stains. In fact, it's nearly as hard as synthetic diamond - only surpassed in strength by actual diamonds themselves!

4. Passivation

Passivation surface treatment is to allow the surface of the stainless steel parts to react with the passivation agent to form a stable passivation film, thereby protecting the stainless steel substrate from being oxidized and corroded and causing rust. It is applied for SUS200, SUS300, and SUS400 series stainless steel parts.

5. Polish

Stainless steel is widely used because of its high corrosion resistance and decorative properties, especially in medical appliances, food industry appliances, tableware, kitchen appliances, etc. Therefore, the requirement for the surface treatment of the production of such appliances is to completely remove the harmful substances on the surface. This will need the polish process. There are 3 types of polishing methods: Mirror polishing, chemical polishing, electrolytic polishing.

(1) Mirror polish

Mirror surface treatment of stainless steel products refers to a kind of bright surface effect obtained by using high-quality oilstone, diamond grinding paste and different grades of sandpaper, through polishing and grinding equipment, through rough grinding, middle grinding and fine grinding.

(2) Chemical polish

In addition to obtaining a clean surface, chemical polishing also removes manufacturing imperfections such as rust and oxidation from carbon steel surfaces. It's useful for preventing localized corrosion resistance which will increase the strength of your fasteners while extending their life span!

(3) Electrochemical polishing

Stainless steel electrolytic polishing is to hang stainless steel workpiece on the anode, The anode electrolytic machining is carried out in the electrolytic polishing solution. Electrolytic polishing is a special anode process. During the entire anode electrolytic polishing process, the surface of stainless steel products undergoes two contradictory processes at the same time, that is, the continuous formation and dissolution of oxide films on the metal surface. The surface of the stainless steel product is levelled to achieve a highly smooth and glossy appearance, which satisfies the purpose of polishing and finishing the surface of the stainless steel product.

6. Brush

Stainless steel s brush generally has several effects: straight wire pattern, snow pattern, nylon pattern. A straight wire pattern is an uninterrupted pattern from top to bottom, and generally, the fixed wire drawing machine can move back and forth. Snow pattern is the most popular one, it is made up of a little bit of orderly dots, and can be used with insect sandpaper to achieve the effect. Nylon pattern is composed of lines of different lengths. Because of the soft texture of the nylon wheel, uneven parts can be ground to reach the nylon pattern.


7. Electroless Nickel Plating

Nickel plating also applies to carbon steel parts, CNC brass parts. Can stainless steel machining parts be nickel-plated?Stainless steel itself has the advantages of strong corrosion resistance and a beautiful surface. Can meet the general purpose. However, because the products are mostly used in the environment of marine climate and have higher requirements for the surface hardness of some stainless steel parts, it is necessary to improve the corrosion resistance and hardness through surface treatment, and the geometry of these parts The shapes are more complicated, and it is impossible to obtain the plating layer of the grid by electroplating, so electroless nickel plating is used.

8. Black Oxide

Blackening is a common method of chemical surface treatment. The principle is to produce an oxide film on the metal surface to isolate the air and achieve the purpose of rust prevention. Blackening treatment can be used when appearance requirements are not high, and the surface of carbon steel parts can be blackened.

9. Chrome

(1) Bright Chrome

Chrome plating refers to the act of plating chromium as a plating layer on other metals. Metal chromium is easily passivated in the air, and a very thin passivation film is formed on the surface, thus showing the properties of precious metals. Bright chrome could make stainless steel machining parts with very shiny and bright surfaces.

(2) Hard Chrome

Hard Chrome is an industrial process that is able to provide a thick, protective barrier for your parts. This will be able to provide a much higher level of wear and corrosive protection for your parts. Hard Chrome is certainly an option for Stainless Steel parts, but may not be suitable should your component/product need to meet REACH standards.


The above is the surface treatments of common stainless steel machining parts. In addition, stainless steel parts can also be sprayed, colored, etc. Worthy Hardware has been working for more than 25 years in CNC machining and is able to process metal alloys as well as plastics with over 50 types of material. Meanwhile, we could handle more than 30 types of surface treatment: electrochemical polishing, chemical oxidation, vacuum evaporation plating, powder coating, electroless plating, electrochemical oxidation with low cost. Are you ready to send your parts to us? Just do now! We will be your one-stop partner for all your CNC machining projects.


Worthy Hardware is a CNC manufacturing and sheet metal fabrication company,including CNC machining services,CNC milling services, CNC turning services, laser cutting services and stamping services.Call us +86-76989919645 or email us [email protected] for more discounts for your projects.