SUS304 HL (brushed material) is a part made by applying brushed surface treatment to stainless steel.
It is also widely used in building materials, home appliances, interior decoration, etc., covering many products around us.
This time, Huaxiao Metal will introduce the advantages and disadvantages of SUS304 HL (brushed material), its uses, and the differences from other surface treatments.
What is SUS304 HL (Drawn Material)?
Stainless steel is an alloy of iron and chromium and is used in various applications such as building materials and home appliances.
There are several types of stainless steel according to the crystal structure. Among them, “SUS304” is typically stainless steel with strong rust and corrosion resistance, and parts made by drawing SUS304 are called “SUS304 HL”.
What is the drawing of SUS304 HL?
Brushing is a surface treatment method that applies many hair-like (drawn) scratches in a single direction. It is a type of physical grinding (processing that physically grinds an object with a polishing agent, etc.) and is represented by the symbol “HL” (abbreviation of Hairline).
The purpose of brushing is ultimate “decoration”.
Stainless steel such as SUS304 is used in various fields due to its strength and rust resistance, and is required to have various decorative properties such as “metallic feel”, “glossiness”, and “high-end feel” depending on the application.
SUS304 HL, which is made of brushed stainless steel, retains a matte feel and can give people a high-end, mature, calm, and sharp impression. This effect is often used in high-end metal watches, taking the example of things around us.
Brushing is sometimes performed as a post-processing of plating, welding, etc. Sometimes other decorative treatments such as painting are performed after brushing.
What is the method of Hairline?
Brushing of SUS304 is usually performed using a belt grinder.
When using a belt grinder, a grinding belt (annular belt with the polishing agent) of about P150 to P240 mesh is set on the belt grinder and rotated at high speed. Then, the material to be processed is pressed against the rotating belt and the surface is polished in one direction, thereby performing hair processing.
The style of brushing can also be changed by changing the type of grinding belt and the grinding method. For example, the thickness and shape of the brushing can be changed, or the brushing can be crossed.
Advantages and Disadvantages of Brushing
SUS304 HL has the following advantages.
• Scratches, distortions, and unevenness are not noticeable
Since the parts that have been brushed are already scratched in one direction, it is almost impossible to detect even if they are damaged in the same direction as the brushing. In addition, distortions and unevenness are not noticeable. Therefore, brushing is effective for parts that are easily damaged during use, such as watch straps and home appliances.
• Matt finish, which can create a sense of luxury.
Brushing stainless steel will become matte. Compared with the case of “mirror finishing” where the surface is polished, it can present a metallic texture, giving a sense of luxury, maturity, and calmness. Brushing is very suitable for interior design and furniture that wants to show elegance.
• It can form unevenness and has an anti-slip effect.
Brushing can produce fine unevenness on the surface of stainless steel, which has an anti-slip effect. For the purpose of anti-slip, automobile pedal guards are sometimes brushed.
• Grinding method and direction enhance design
Various designs can be achieved by changing the grain size of the grinding belt and the grinding method. It is also possible to engrave patterns with fine meshes or cross-draw like linen.
• Can be produced at a relatively low cost (when using a belt grinder)
By continuously grinding multiple SUS304 plates with a belt, SUS304 HL can be mass-produced at a relatively low cost. However, on the contrary, it may be expensive to process a single product.
Brushing of SUS304 HL also has disadvantages. Please pay attention to the following points when performing brushing.
• Brushing becomes lighter due to aging
Brushing is ultimately used for decoration, not for processing to improve durability like plating. Therefore, the brushing will gradually become lighter due to aging, and the effect will also decrease.
• Scratches perpendicular to the brushing are more noticeable
Brushing makes scratches in the same direction as the brushing less noticeable, but on the contrary, scratches perpendicular to the brushing direction are often more noticeable. Therefore, it is important to determine the direction of brushing based on which direction the part is likely to be damaged. Main Applications of SUS304 HL.
SUS304 Stainless Steel Surface Processing List
SUS304 has various surface finishing processes other than hairline. Let’s compare the representative surface finishing processes.
| Types | State After Processing | Processing Method | Feature | Uses |
| HL（Brushing） | ・Apply fine scratches like hair (brushed) in one direction ・With a matte dull luster | ・Use a P150 to P240 grit abrasive tape to grind the surface in one direction. | ・Can present a calm temperament and a sense of luxury ・Anti-slip effect ・Various designs | ・Building materials ・Kitchen equipment ・Home appliances ・Decorations ・Transportation equipment ・Precision equipment |
| No.1 | ・Silver white ・Rough texture ・Matt | ・Annealing after hot rolling → pickling and finishing | ・For applications where surface gloss is not required | ・Structural parts ・Cold-rolled base materials |
| No.2B | ・Compared to No.2D finishing, it is smoother and slightly glossy ・Relatively smooth | ・For No.2D material (annealing after cold rolling → pickling and finishing), cold rolling (skin rolling) is lightly performed to give an appropriate gloss. | ・The most commonly used finishing method for commercially available stainless steel products | ・General materials ・Building materials |
| #400 | ・Close to mirror surface ・Some streaks | ・Using P400 mesh polishing wheel, polishing No.2B material | ・A type of mirror finish ・Glossier than 2B ・Glossier than BA | ・Building materials ・Kitchen equipment |
| No.8（Mirror） | ・Near mirror finish ・No polishing marks | ・Generally, the particle size of the polishing agent is gradually increased. After general polishing, the mirror polishing wheel is used for final polishing. | ・Mirror finish with the highest light reflectivity ・Scratches are noticeable, so use in areas that are less likely to be damaged ・Glossy ・Luxury ・Feeling of weight | ・Building materials (ceiling panels, etc.) ・Decorations ・Reflectors |
※ “P〇〇〇”: indicates mesh (coarseness or particle size of polishing agent). The smaller the number, the coarser the polishing marks.
※ “No. 〇”: indicates gloss intensity. The smaller the number, the glossier it is.
Surface Finishing: HL (brushed)
This is a surface finishing method that uses a grinding belt to grind the surface of SUS304 in a single direction, giving fine hair-like (brushed) scratches. It can present a calm temperament and a sense of luxury.
Surface finishing: No.1
No.1 is a surface treatment method that performs annealing after hot rolling (heating to above the recrystallization temperature and softening and rolling) of SUS304 and then washes the surface with acid. Materials that have undergone No.1 finishing are also called “HOT materials” or “pickling materials”.
Its main features are silvery white, matte, and rough texture (similar to pear skin). It is used for applications that do not require surface gloss.
Surface finishing: No.2B
No.2B material is a material that has undergone a treatment called skinning rolling on No.2D material.
No.2D material is a part that is annealed after cold rolling (rolling at room temperature) and then cleaned with acid. It is characterized by gray and low gloss. Skin rolling is a light rolling performed to obtain moderate gloss. No.2B material, which is skin-rolled on No.2D material, is smoother and slightly glossier than No.2D material.
No.2B is the most commonly used method for surface finishing of SUS304, and most of the SUS304 products on the market are No.2B material.
Cold Rolled 304L/304 Stainless Steel Coil
Surface Finishing: #400
#400 is a finishing method that uses a P400-mesh polishing wheel to polish the surface of No.2B material, which is a so-called “mirror finishing”. #400 material has a stronger gloss than No.2B material, but it is not a complete mirror surface, and there are slight streaks on its surface.
#400 material is used for building materials, kitchen equipment, etc.
304 18 Guage Stainless Steel Sheets To Canada
Surface Finishing: No.8 (mirror)
No.8 is a type of mirror finishing like #400 and is the closest mirror finishing method to SUS304. The gloss of the No.8 material is stronger than that of the #400 material, and there are no streaks or polishing marks on its surface. There are cases where No.8 material is used as a mirror.
How to Polish Stainless Steel to a Mirror Finish
When manufacturing No.8 material, polishing is performed while gradually increasing the particle size of the polishing agent, and the final polishing is performed using a mirror polishing wheel. No.8 material is used as a building material and decoration because of its gloss, high-end feel, and weight, but be careful that it is easily damaged.
In Conclusion
SUS304 HL is a component made by applying a hair-like line to the surface of SUS304, a type of stainless steel. The brushing process makes scratches and unevenness less noticeable while giving a high-end, mature feel. The unevenness of the brushing also has a non-slip effect.
SUS304 HL is an excellent component used in many products such as building materials, kitchen equipment, and decorations. It is expected that its uses will continue to expand in the future by utilizing its characteristics.