What are the basic surface treatments of stainless steel sheets?

January 6, 2021
In this post, you'll read:There are many different types of surface treatment for stainless steel sheets. The surface treatment is essential as it gives both practical and aesthetic purposes.

Table of Contents

There are many different types of surface treatment for stainless steel sheets. The surface treatment is essential as it gives both practical and aesthetic purposes. If your stainless steel sheets are for display purposes, the surface treatment is vital to achieving the designed look. If your stainless steel sheets are for non-decorative application, the surface treatment might still be significant. That is because the surface finishes for your stainless steel sheet will affect their durability, corrosion resistance, and maintenance needs.

This is an image of stainless steel sheets.

No.1 

The process of No.1 surface treatment includes hot rolling and annealing. You will then have to pickle and passivate the stainless steel, which produces a non-uniform surface that is both rough and dull.

This is an image of No.1 stainless steel sheet.

Application

It is a common choice for industrial equipment where aesthetics are not necessary.

It is also the starting material for the other surface treatments, such as the 2B and 2D surface finishes.

2B

2B surface treatment is accomplished by cold-rolling the stainless steel sheets. The effect is a bright matte finish that is more reflective than 2D surfaces. It is the cheapest finish as you are not required to process it further.

This is an image of 2B stainless steel sheet.

Application

  1. 2B surface-treated stainless steel sheets are the most common types that you can find on the market. You will see them in your daily household appliances and interior designs. Often, you can find them in areas where aesthetics is not as important. 
  2. They are also used for deep drawing and can be polished to achieve the final finish.
  3. You can find 2B stainless steel sheets in many types of equipment such as chemical plants and sewage. The appearance of your stainless steel sheets is not a priority in those places. The cost-efficiency of 2B finishes makes them a top choice for these uses

2D

The 2D surface treatment will make your stainless steel non-reflective. It appears as a uniformed and dull silver-grey surface. This surface treatment is accomplished when your stainless steel sheets undergo cold rolling, heat treating, and pickling. Pickling after heat treatment helps you to remove the chromium inside the stainless steel.

This is an image of 2D stainless steel sheet.

Application:

  1. The 2D stainless steel surface treatment is applied to stainless steel surfaces that are used for industrial applications. You would opt for 2D stainless steel surface treatment when there is painting involved. This is because the No. 2D stainless steel finish is an excellent paint adhesion.
  2. The 2D stainless steel surface treatment is also great for deep drawing of stainless steel sheets. This is a process where stainless steel sheets are drawn into complex shapes. You can achieve this by applying pressure to stretch the stainless steel. 2D finishes are optimal for this purpose as the dull surface retains the lubricant during the deep drawing process. 

BA

BA stainless steel surface treatment is short for Bright Annealed finish. The thinner the stainless steel sheets, the smoother and brighter this finish becomes. The end product is reflective and is similar to the mirror surface-treated stainless steel sheets. This type of surface treatment is often used for Type 304 stainless steel.

This is an image of BA stainless steel sheet.

Application

  1. The smoothness of a bright annealed stainless steel makes it perfect for home applications. For example, it acts as an excellent cover for the interior of washing machines. This is because it provides a polished and smooth surface that allows you to wash clothes without them being spoilt by friction
  2. It is also an excellent choice for surfaces that come into constant contact with water, such as sinks. The anti-corrosive properties will help your stainless steel sheets maintain their shine for a longer time.

Mirror

You can guess by its name what the effect of a mirror surface treatment is. This kind of stainless steel surface treatment is also known as the No. 8 stainless steel surface treatment. Mirror finishes are achieved by intensive polishing of the stainless steel sheets. The result is a stainless steel sheet that is bright and reflective

The uniformed surface also makes it much easier to clean and maintain. You can choose from 3 different types of mirror polishing at FTSSS. These include general grinding (8k), fine grinding (8k – 10k), and ultra-precision grinding (10k). As expected, ultra-precision grinding provides the best result. You will be able to see maximum reflectivity in your stainless steel sheets while obtaining minimal flaws. It is because ultra-precision grinding utilizes a higher number of grinding heads. Consequently, the polishing is optimized.

You would not use mirror stainless steel sheets for all applications. Its polished surface would mean that any stains or marking becomes obvious. In high traffic areas like public transport or park railings, mirror surface treatment would not be the right choice.

Application

  1. The bumpers on our cars nowadays are made from complex plastic materials. On the other hand, firetrucks still use metal bumpers, and mirror stainless steel bumper is one of them. It can be polished to look like its counterpart chrome. You are also unlikely to see it rust, unlike chrome bumpers. Moreover, if it collides with any structure, you can push it back into shape and shine it, making it as good as new. 
  2. Mirror finishes also provide hygienic purposes for your appliances and equipment. The smoothness of its surface means that particles do not become trapped on its surface. As such, you would see medical equipment and food processing machinery, making use of mirror stainless steel sheets.
  3. You can also use mirror stainless steel sheets for aesthetic purposes. In places like hotels and high-end restaurants, mirror stainless steel will provide a chic and elegant vibe. You might have to fork out more money to maintain the shine on your stainless steel sheets, but it will be well worth the effort. You can also incorporate it into your home as its shiny nature makes it a good companion for other materials. You can pair it with wood, leather and many others. As long as you maintain the shine, you can impress your guests.
This is an image of stainless steel sheet architecture.

Hairline

You can see that the surface of hairline stainless steel sheets is covered with lines. The lines resemble human hair and thus are known as hairline finishes. This is accomplished by using a specialized grinding technique that can be customized to your preferences. You will be able to choose the intensity of the hairline on your stainless steel sheets. You can choose from 3 different types of hairline polishing at FTSSS. The resulting matte surface is easy to clean and provides a minimalistic look. The lack of light reflection offers a calm environment. It also does not leave fingerprint marks as compared to the mirror stainless steel sheets. Scratches on hairline stainless steel sheets will also not be as distinguishable as mirror stainless steel sheets. However, the grooves in the hairline stainless steel sheets mean that rust might occur faster. As such, it is not recommended for you to use hairline stainless steel sheets in places that come into contact with water. 

This is an image of hairline stainless steel sheet.

Application

  1. You can see hairline stainless steel sheets in interior design where aesthetics is a priority. You can find them in high traffic areas of hotels and shopping centers. They can maintain their elegance despite being in contact with fingerprint marks.
  2. You can also choose to use hairline stainless steel sheets in your home. If you are going for a more down to earth look, the matte finish will provide you with a minimalistic effect.

No.4

No. 4 stainless steel finish is produced by brushing the stainless steel surface with abrasive belts. You will be able to eliminate a minimal portion of the metal surface, resulting in a brushed effect. No.4 stainless steel finish has the lowest surface shine and reflectivity.

Also known as the workhorse finish, this stainless steel surface is easy to clean and maintain. You can distinguish no.4 stainless steel surface treatment by their short parallel surface lines. For more details of No.4 sheets, please check the specific explanation at FTSSS.

Application

1. Architecture and design
No.4 stainless steel finish is directional. This makes it easy to match panels in interior designs. To determine which direction the lines on the stainless steel sheet is, you can brush the surface with the back of your fingernail. Only one direction will leave a mark.

2. Food production equipment
A lot of fresh and raw products have a shelf life. This is true for dairy products, which will require their storage equipment to be hygienic. You can customize your No.4 stainless steel finish with finer grits so that the finish is smoother and less likely to trap bacteria.

Vibration

Vibration sheets, also known as the non-directional hairline finish, provides you with an interesting visual effect. Depending on where you stand, the stainless steel sheet will have a different appearance. For example, up close, you will see unsystematic lines on the sheets. If you stand further away, you will see circular lines on the stainless steel sheets. You can obtain vibration stainless steel sheets by using a special polishing oil during the production process. You can also choose the intensity of the finishing shine for your stainless steel sheets. For more details of vibration sheets, please check the specific explanation at FTSSS.

This is an image of vibration stainless steel sheet.

Application

Vibration stainless steel sheets are used for aesthetic purposes. Many places use vibration stainless steel sheets to improve the overall style. You can set your home apart by choosing the more unique vibration stainless steel sheets over the typical hairline stainless steel sheets.

Bead Blast

Bead blasted stainless steel sheets is a streak-free finish. You can obtain bead plastic stainless steel sheets by spraying zirconium beads or abrasive sand on the surfaces. The beads allow you to make tiny cuts on the surface of the stainless steel sheets. This removes small amounts of metal from the body. Spraying at high speeds results in a soft satin reflection with low reflectivity. It appears as a beautiful and uniform matte surface. It also becomes an excellent surface for paint retention, making it the right choice if you plan on painting the stainless steel surfaces. Moreover, bead blasting can also help the stainless steel sheets to have increased surface hardness. For more details of bead blasted sheets, please check the specific explanation at FTSSS.

This is an image of bead blasted stainless steel sheet.

Application 

  1. The architecture industry is a fan of bead-blasted sheets. The improved surface hardness and durability that bead blasting provides make it an excellent choice for cladding purposes.
  2. You can also find bead blasted stainless steel sheets in decoration applications. For example, its streak-free finish makes it a suitable choice for a panel to panel matching.

Conclusion

At FTSSS, we also provide an additional surface coating for your stainless steel sheets on top of the surface treatments above. This includes anti-fingerprint or PVD coating that adds another dimension to your product. If you are unsure of the most suitable stainless steel surface treatment for your product, please contact us, and we will help you make the best choice.

Hi, I am Linda, FTSSS blog writer . I have been working on stainless steel  since I graduated from university. How time flies!  13 years have slipped away from me. ‘Stay hungry, Stay foolish.’ I am walking steadily on the road of seeking knowledge every day.

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