The various surface processing of stainless steel pipe
broadens its application fields-different surface processing makes the surface of stainless steel different, making it unique in its application.
There are many reasons why surface finishing of stainless steel is important in construction applications.
Corrosive environments require smooth surfaces because smooth surfaces are not prone to fouling. The accumulation of dirt can cause stainless steel to rust and even cause corrosion.
In spacious halls, stainless steel is the most commonly used material for elevator decorative panels. Although fingerprints on the surface can be wiped off, they affect the appearance, so it is best to choose a suitable surface to prevent fingerprints from leaving.
Hygienic conditions are important in many industries, such as food processing, catering, brewing, and chemical industries. In these applications, surfaces must be easy to clean every day, and chemical cleaning agents are often used.
Stainless steel is the best material in this regard. In public places, the surface of stainless steel is often scrawled with graffiti. However, an important feature of it is that they can be washed away. This is a significant feature of stainless steel over aluminum. The surface of aluminum tends to leave marks, which are often difficult to remove. When cleaning the surface of stainless steel, you should clean it along the lines of the stainless steel, because some surface processing lines are one-way.
Stainless steel is most suitable for use in hospitals or other areas where hygiene is critical, such as food processing, catering, brewing, and chemical industries, not only because it is easy to clean every day, sometimes using chemical cleaning agents, but also because it is less likely to breed bacteria. Tests have shown that stainless steel performs the same as glass and ceramics in this regard.
1. The natural look of stainless steel. Stainless steel gives people a natural feeling of solidity and brightness, and its natural color softly reflects the color of the surrounding environment.
2. Basic types of surface processing. There are roughly five surface treatments that can be used for stainless steel, and they can be combined to create more final products. The five categories are rolling surface processing, mechanical surface processing, chemical surface processing, textured surface processing, and colored surface processing. There are also specialized finishes, but no matter which finish you specify, the following steps should be followed:
① Agree with the manufacturer on the required surface processing. It is best to prepare a sample as a standard for future mass production.
② When used in large areas (such as composite panels), it must be ensured that the base coils or coils used are from the same batch.
③In many construction applications, such as inside elevators, although fingerprints can be wiped off, they are very unsightly. If you choose a cloth surface, it will not be so obvious. Mirror stainless steel must not be used in these sensitive areas.
④ The manufacturing process should be taken into consideration when selecting surface processing. For example, to remove weld beads, the weld may need to be ground and the original surface processing must be restored. Patterned boards are difficult or even impossible to meet this requirement.
⑤ For some surface processing, grinding, or polishing, the texture is directional and is called unidirectional. If the lines are made vertical rather than horizontal when used, dirt will be less likely to adhere to it and it will be easier to clean.
⑥No matter what kind of finishing is used, additional process steps are required, thus increasing costs. Therefore, be careful when choosing surface processing. Therefore, relevant personnel such as architects, designers, and manufacturers need to understand the surface processing of stainless steel. Through friendly cooperation and mutual exchanges, the desired results will be achieved.
⑦Based on our experience, we do not recommend using aluminum oxide as an abrasive unless great care is taken during use. It is best to use silicon carbide abrasives.
3． Standard surface finish. Many types of surface processing have been represented by numbers or other classification methods, and they have been incorporated into relevant standards.
4. Rolling surface processing. There are three basic rolling surface treatments for plates and strips, which are represented by the plate and strip production processes.
No.1: Hot rolled, annealed, pickled, and descaled. The surface of the treated steel plate is a dull surface and a bit rough.
No.2D: Better surface processing than N0.1, but also a dull surface. After cold rolling, annealing, descaling, and finally light rolling with matte rollers.
No.2B: This is the most commonly used in construction applications. Except for the final light cold rolling with a polishing roller after annealing and descaling, the other processes are the same as 2D. The surface is slightly shiny and can be polished.
No.2B Bright Annealed: This is a reflective surface that is rolled with polishing rollers and finally annealed in a controlled atmosphere. Bright annealing still maintains its reflective surface and does not produce scale.
Since no oxidation reaction occurs during bright annealing, pickling, and passivation treatments are not required.
5. Polished surface processing
No.3: Represented by 3A and 3B.
3A: The surface is evenly ground and the abrasive grain size is 80~100.
3B: Matt surface polishing, with uniform straight lines on the surface. It is usually polished once with an abrasive belt with a grit of 180~200 on the 2A or 2B board.
No. 4: One-way surface finish, not very reflective, this finish is probably the most versatile in architectural applications. The process steps are to first polish with coarse abrasives and finally, grind with 180-grit abrasives.
No.6: It is a further improvement on No.4. It is polished with a Tampico polishing brush in abrasive and oil medium. 4 surfaces. This surface treatment is not included in "British Standard 1449", but can be found in the American Standard.
No.7: It is called bright polishing, which is polishing the surface that has been ground very finely but still has grinding marks.
Usually, the 2A or 2B plate is used, with a fiber or cloth polishing wheel and the corresponding polishing paste.
No.8: Mirror polished surface with high reflectivity, often called mirror surface processing because the reflected image is very clear.
Polish the stainless steel continuously with a fine abrasive and then with a very fine polishing paste. In architectural applications, it should be noted that such surfaces may leave fingerprints if used in areas with high traffic or where people touch them frequently. Fingerprints can of course be erased, but sometimes they affect the appearance. Surface processing described in "official" standards and literature is only a general introduction, and samples can most intuitively represent the types of surface processing. Polishing or metal finishing manufacturers will provide samples of various surface finishes and users should discuss them with them.
6. Surface roughness. The classification of rolled surface processing and polished surface processing indicates the degree to which it can be achieved. Another effective expression method is the measurement of surface roughness. The standard measurement method is called CLA (Centre Line Average), in which the measuring instrument moves laterally across the surface of the steel plate and records the amplitude of the peak and valley changes. The smaller the CLA number, the smoother the surface. The result of the different grades can be seen from the surface finish and CLA numbers in the table below.
7. Mechanical polishing. Note: We should remember that grinding with sandpaper or abrasive belts during grinding operations is a polishing-cutting operation, leaving very fine lines on the surface of the steel plate. We have had trouble using aluminum oxide as an abrasive, partly due to pressure issues. Any grinding parts of the equipment, such as abrasive belts and grinding wheels, must not be used on other non-stainless steel materials before use. Because this will contaminate the stainless steel surface. To ensure the consistency of surface processing, new grinding wheels or abrasive belts should be tried on scrap materials with the same composition first so that the same samples can be compared.
8. Electrolytic polishing. This is a metal removal process in which stainless steel acts as an anode in an electrolyte and is energized to remove metal from the surface. The process is often used for parts whose shapes are difficult to polish using traditional methods. This process is often used on the surface of cold-rolled steel sheets because the surface is smoother than that of hot-rolled steel sheets. However, electrolytic polishing will make surface impurities more obvious, especially titanium and niobium-stabilized materials, which will cause differences in the weld area due to granular impurities. Small weld scars and sharp edges can be removed by this process. The process focuses on protruding parts of the surface, dissolving them preferentially. The electrolytic polishing process is to immerse stainless steel in heated liquid. The proportion of the liquid involves many proprietary technologies and patented technologies. Electrolytic polishing of austenitic stainless steel works well.
9. Textured surface processing. Many types of patterns can be used for stainless steel.
The advantages of adding patterns or textured surface processing to steel plates are as follows:
① Reduce "oil can-ning", which is a term used to describe the surface of shiny materials that do not look flat from an optical perspective. For example: even if a large-area decorative board is stretched or straightened by tension, it is difficult to make the surface completely flat, so the metal roof material will shrink.