Now people have generally used stainless steel products. In fact, there are many types of stainless steel. Moreover，people can’t distinguish them my eyes. Meanwhile, different types of stainless steel have different uses. And the No.4 stainless steel coil is a polished finish.
Moreover, its production process and standards are somewhat different from other types.
First, let’s understand what is No. 4 stainless steel coil.
No.4 stainless steel coil is a universal stainless steel finish. People extend evenly along the length of the coil. Moreover, people use abrasive machinery to polish and finish stainless steel. And then people use 120-320 grit sandpaper for polishing. In this way, a small amount of metal on the surface can be removed without affecting the thickness of its stainless steel. In this way, people made the No.4 stainless steel coil.
The polished lines on its surface are very thin and its surface is more reflective.
(Another type of steel coil with a surface proceeded is mirror 8k stainless steel, you can check the information on Detailed introduction of mirror 8k stainless steel coil)
There are very fine refractory materials in the abrasive belt. Such as silica, alumina.
Polishers in stainless steel plants lubricate the cutting action by filling the strip with oil. So，this helps keep it cool and provides a finer, more uniform surface.
Because the production process is variable, not every No.4 finished product looks the same. Sometimes, different manufacturers of abrasive belts have different grain sizes. So the service life of No.4 stainless steel coils is also different.
When people choose the No.4 stainless steel coil, its appearance must match the job requirements. Therefore, a project should use the same batch of No.4 stainless steel coil material package.
By the way, compared to 2B or BA finishes, No. 4 is easier to achieve a reasonable appearance match.
And, when using it, follow the direction of the polishing line of No. 4 stainless steel coil.
Compared to 2B or BA finishes, No. 4 is easier to achieve a reasonable Moreover, No. 4 finishing is easier to achieve a reasonable match in appearance.
The finish that people produce by using abrasives is grinding or polishing finish.
Moreover, the standard of No.4 stainless steel is depending on the general surface treatment used to produce widely-used restaurant equipment, kitchen equipment, storefronts and food processing.
Besides, people also use the roughness of the abrasive to define the No. 4 surface treatment agent.
And, new editions of American and European standards define the surface roughness limits.
Meanwhile, in Australia, the convention is to use only “No 4” as a description of polished finishes, not rolled finishes.
The European standard EN10088-2 defines two finishes, namely “2J” and “2K”. There is no provision for the appearance of the roughness of “2J” coatings, but “2K” is defined as surface Ra less than 0.5 microns.
However, these words describe a process and do not specify the result.
Moreover, the roughness of No. 4 does not change with the thickness of the steel.
Although you can specify its roughness to better control the corrosion performance of the surface. But it only has some correlation with the appearance of No.4. And it is difficult to measure its roughness repeatedly.
Besides, topcoats with the same gloss may look completely different. Therefore, its gloss is not suitable for the specification of key tasks in construction.
For critical works, it is best to use reference samples viewed under agreed conditions to specify the appearance. And this sample should be large enough so that they can be viewed from various angles and distances-the appearance will vary with the viewing angle.
Because sulfides are present in all steels. Moreover, they can act as corrosion catalysts. Therefore, when there is relatively large damage on the steel surface, it is difficult to keep its surface clean.
In general, the corrosion resistance of No. 4 is often lower than that of the finished BA or 2B finishes.
Moreover, the surface of No. 4 is also related to corrosion. When the surface is vertical first, its corrosion resistance will be better.
In some places where the requirements for corrosion resistance are not very high, its corrosion resistance will not affect the normal use of the product.
However, under conditions such as the ocean and the atmosphere, its corrosive will be lower.
But some manufacturers will take some measures to improve its corrosion resistance. For example, pickling the surface of No. 4 stainless steel in a mixture of hydrofluoric acid and nitric acid.
Or passivize its surface in a nitric acid solution.
And then, this can improve the corrosion resistance of No.4 stainless steel coating.
Besides, the privation treatment can dissolve the sulfide on the surface of No.4. Moreover, this will not change its appearance.
Similarly, pickling can also remove sulfide on its surface. However, its appearance will darken.
Unfortunately, though these two methods, even if people control the temperature and contact time of the treatment process, a completely smooth and uniform surface cannot be obtained. Moreover, people cannot often passivize No. 4 stainless steel.
Therefore, electro-polishing the surface of No. 4 stainless steel can improve its corrosion resistance. At the same time, it can brighten its surface.
There are two types of No.4 stainless steel.
Next, let’s take a look at it in detail
People polishing the surface of stainless steel can improve the overall finish of stainless steel products
Moreover, stainless steel polishing can improve the overall surface finish of any stainless steel product.
Moreover, this can make steel meet more sanitary requirements.
However, there is more than one way to polish stainless steel. Therefore, their effects are also different.
Now, let’s take a look at them one by one below.
Hot rolled stainless steel is a semi-finished product. Then, it has to pass through cold rolling treatment.
For its process, people hot roll, pickle the stainless steel first. And then put it on the polishing rod for cold rolling.
Besides, the required thickness of the finished product determines the frequency of this process.
People continuously polish the bright coil. In this way, a high-reflectivity finish can be obtained. Moreover, this type of surface treatment is commonly used in car and home decoration, tableware, utensils, fire extinguishers and sanitary equipment.
People customized No.4 stainless steel for different purposes. Therefore, its application areas are many.
For manufacturers, the surface treatment of No. 4 is directional. Moreover, matching surfaces and repair welding are easy. Therefore, people usually use it wherever welding seams and other original markings need to be repaired. But it is difficult for people to achieve these in 2B or BA finishes.
For users, they can also easily eliminate any damage on the surface of No.4.
But the surface of No.4 stainless steel coil is darker than other common surfaces. For example, 2B and BA. Therefore, people usually use it on occasions that require low reflectivity and gloss.
Some of the most famous buildings in the world are made of polished stainless steel. Moreover, polished stainless steel is also used in many high-rise buildings everywhere.
Usually, the roof gutters, roofs, light poles, elevators, public seats and signs we usually see are all polished stainless steel products.
For architects and designers, the surface of No.4 stainless steel can achieve the glossiness of the panel. Moreover, it has the best surface flatness.
Special requirements are attached to the J-shaped finish of Ou Biao Li. This makes it sufficiently corrosion-resistant for exterior buildings.
Polished stainless steel provides a highly hygienic surface. Moreover, it is easy for people to clean it. Therefore, it has many kitchen and food applications.
Because No. 4 stainless steel is very easy to clean, polished stainless steel is usually the first choice for these applications.
In addition to commercial kitchens, we can see polished stainless in beer barrels, milk silos, juice tanks, pipes, beer and wine fermentation tanks, cheese barrels, tables and display cabinets.
Polished stainless steel has good corrosion resistance. Moreover, its weight is relatively light. Therefore, it has many applications in vehicles and transportation.
For example, No. 4 stainless steel is used in automobile exhaust systems, wiper arms, wheel covers, milk tankers, trucks, bus frames and offshore chemical tankers.
And, when the service life of stainless steel expires, people will reuse stainless steel.
If people don’t reuse it and will recycle it.
In general, the scrap value of nickel-containing grades is high. Therefore, most stainless steels today are manufactured using large amounts of waste stainless steel.
This not only does not sacrifice the quality of stainless steel but also develops in the direction of sustainability and environmental protection.
We all know that one of its advantages is easy to clean. So, how should we clean it and do surface protection?
There is usually a white polyethene plastic film on the No. 4 finish. And the plastic film usually has printed lines on the plastic in the same direction as the No. 4 polish.
Moreover, it is best to keep the film on the steel surface during the manufacturing process. This prevents handling and transportation damage. However, the film has limited resistance to sunlight, and if it is not a black film underneath, people should not place No. 4 stainless steel in the sun for more than one or two hours.
Unfortunately, the film may bake onto the surface. Or it becomes brittle or torn into strips when removed. Or leave the glue on the steel surface.
In this way, the glue on the steel will retain dirt and may cause rapid surface discolouration or tea stains. However, a final wipe with a glass cleaner or window cleaner will ensure no traces.
Therefore, if you suspect that there is glue remaining on the steel, please use the solvent provided by the merchant to wipe the surface.
Besides, if other solvents are used, it is better for people to use them after testing.
People can usually wipe the No. 4 surface with a soft damp cloth.
When cleaning the grease on the surface of No. 4 stainless steel, people usually moisten a soft cloth with ammonia or household liquid grease remover to wipe it. However, using hot water is also very effective.
There is also a kind of stainless steel cleaner that is a white powder. It belongs to sulfa-mic acid products. People can wipe the surface with a damp cloth dipped in the powder. This can brighten the surface.
However, some No. 4 finishes will pull threads and fluff from the fabric when wiping, which is difficult to peel off the steel. Therefore, wiping should always be done in the direction of the polishing line.
No.4 stainless steel coil is a universal stainless steel finish. And there is no definite definition of processing standards. Moreover, the appearance of No.4 stainless steel coil must match the requirements of the work. Therefore, a project should use the same batch of No.4 stainless steel coil material package.
For the polishing types, there are cold-rolled and ground polishing. And people customized No.4 stainless steel for different purposes. Moreover, people customized No.4 stainless steel for different purposes.
Polished stainless steel provides a highly hygienic surface. Moreover, it is easy for people to clean it. So, it has many kitchen and food applications.
Polished stainless steel has good corrosion resistance. Moreover, its weight is relatively light. Therefore, it has many applications in vehicles and transportation.
People can usually wipe the No. 4 surfaces with a soft damp cloth or detergent.
However, do not use abrasive cleaners to clean the surface of No. 4 stainless steel. This may change its appearance.
Moreover, when cleaning, people can reduce fingerprints by applying light oil on the surface.
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