What is No.4 stainless steel sheet?

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Introduction to No.4 stainless steel sheet

No.4 stainless steel sheet is one of the surface effects of stainless steel.

In fact, it is also a polished surface. And its surface is dark and uneven.

Moreover, among the types of stainless steel, it is considered moderately ground stainless steel.

Because of its excellent weld-ability, corrosion resistance, and cleanliness, people use it widely.

Moreover, since the birth of stainless steel for more than a century, its manufacturing process has been very mature.

Therefore, on the basis of No.4 surface treatment, people can also add color to it.

Next, let’s take a closer look at it.

First of all, what is the No.4 stainless steel sheet?

No.4 stainless steel sheet

What is the No.4 stainless steel sheet?

No.4 stainless steel sheet is a brushed finish. And he has a darker and uneven appearance.

Moreover, usually, it has a peelable PVC coating. And this coating prevents scratches during manufacturing and installation.

Usually, it’s surface treatment thickness is 0.20mm to 6.0mm.

As for its surface roughness, it is usually 25 microinches or less.

Moreover, the roughness of the surface does not change with the thickness of the steel.

Meanwhile, it is also the easiest facing to maintain.

Therefore, people can often see No.4 finishes in kitchen appliances and other places.

However, its surface treatment effect is not always the same.

Next, we come to the standard of its surface treatment effect.

Standard of No.4 finish

The current standard is defined by the roughness of general-purpose surfaces used in restaurant equipment, storefronts, and food processing.

And the new American and European standards define the limit of its surface roughness:

ASTM A480 defines its surface roughness as one or both sides of general polishing.

Moreover, one can produce linear texture finishes by mechanical polishing or rolling.

And skilled operators can usually mix this topcoat.

However, in Australia, people use No. 4 to describe polished finishes.

Instead of using it to describe rolled finishes.

The European standard defines two No. 4 finishes: 2J and 2K.

And 2K means that the surface Ra is less than 0.5 microns.

For J-shaped finishes, it needs to have the corrosion resistance required for ships and exterior buildings.

According to the above, we said, people, can use Ra to better control the roughness of the No.4 stainless steel sheet.

However, it is only related to appearance.

Moreover, it is difficult to measure it repeatedly.

Meanwhile, sometimes two topcoats with the same Ra may look different.

Although Ra can be specified to better control the corrosion performance of the surface, it only has a moderate correlation with the appearance.

And it is difficult to repeat the measurement.

Therefore, for important work, it is best to use reference samples viewed under agreed conditions to specify its appearance.

Moreover, the appearance of the sample may vary with the viewing angle.

Therefore, this sample should be large enough.

In this way, people can observe their appearance from various angles and distances.

standard of roughness

How to make No.4 stainless steel sheet?

Usually, people use abrasive belts and polishing machines to make No. 4 surfaces.

The abrasive belt has very fine refractory particles.

For example, silica, alumina, and zirconia.

And they are in the adhesive layer of flexible cloth or paper backing.

As for the width of the belt, it is wider than the width of stainless steel.

Then, people put the abrasive belt on the roll and run it, and then put the stainless steel on it.

At this time, people use short and parallel polishing lines to make a stainless steel sheet with the No. 4 surface.

Moreover, these polishing lines extend uniformly along the length of the coil.

Meanwhile, the surface of No. 4 is made by mechanical polishing with tapered abrasive.

Moreover, a high grit count can produce finer polishing lines and more reflective finishes.

According to requirements, the final finish can be between 120 and 320 mesh.

In this way, people can remove a small amount of metal on the surface of stainless steel.

Moreover, this does not affect the thickness of the stainless steel sheet.

People heat-treat stainless steel. And this can produce a uniform microstructure.

At this time, people need to ensure that stainless steel meets the requirements of mechanical properties.

And after these processing steps, its surface showed a dark and uneven appearance.

Usually, people call this oxide scale.

Then, people remove it chemically.

Usually, people refer to the process of chemically removing scale as pickling or descaling.

And this is the final step.

When using a polishing machine, people fill the strip with oil to lubricate the cutting action.

And this helps to provide a finer and more uniform surface.

no.4 stainless steel sheet

Properties of No.4 stainless steel sheet

From an objective point of view,it’s properites depend on its chemical composition.

Corrosion resistance

When the chromium content in stainless steel is less than 12%, it has corrosion resistance.

And No. 4 stainless steel sheet is not as prone to corrosion or rust as ordinary steel. However, it is not absolutely rust-free.

When the No. 4 stainless steel sheet is worn, the surface scratches or grooves caused by the wear will expose the sulfide inclusions.

Moreover, it can be a corrosion catalyst.

Moreover, the corrosion resistance of the No. 4 stainless steel sheet depends on the type of stainless steel.

Generally, in aggressive environments, people use 316 grade 4 stainless steel sheets.

At this time, one can ignore the corrosion resistance.

However, in mild applications, the corrosion resistance of No. 4 stainless steel is very good.

However, under more severe conditions.

For example, in marine and industrial environments, people can take measures to improve corrosion resistance:

  1. The corrosion resistance of a smooth surface can be better than the corrosion resistance of a rough surface with a higher degree of alloy.

Moreover, when the vertical lines on the surface of No. 4 stainless steel have better corrosion resistance than the horizontal lines.

Therefore, the finish direction of No. 4 stainless steel is also very important.

2.Passivation treatment can dissolve the sulfide on the surface of the No. 4 stainless steel sheet.

Moreover, this will not change its appearance.

Therefore, people can pickle the surface of No. 4 stainless steel in a mixture of hydrofluoric acid and nitric acid.

Or, people passivate the surface of No. 4 stainless steel in a nitric acid solution.

And these can improve the corrosion resistance of the No.4 stainless steel surface.

However, the pickling treatment is aggressive, it will darken the surface of No. 4 stainless steel.

3.Also, people electropolishing the surface can improve the corrosion resistance and brighten the surface.

Moreover, this can remove the sulfide on the surface of the stainless steel sheet.

In general, the corrosion resistance of the No. 4 stainless steel sheet is usually lower than that of the same grade BA or 2B surface.

corrosion resistance

Types

In metal processing, the most common stainless steel finish is 2B No.4 finish.

Moreover, its reflectivity is not as good as the 2B finish.

However, it has an attractive appearance and good results.

Moreover, different grades of No. 4 stainless steel sheets have different surface finishes.

Meanwhile, according to different uses, people have different requirements for the oxidation and corrosion resistance of stainless steel.

Therefore, it is important to choose the correct type of stainless steel sheet.

Generally, No. 4 cold-rolled surface is suitable for 304, 316, 430, 410, 409 stainless steel and duplex stainless steel sheets.

Moreover, its sliding edge width is usually 1000mm, 1220mm, 1500mm, 1800mm, 2000mm.

Usages of No.4 stainless steel sheet

Grade 4 finishing stainless steel is the main force in the light manufacturing industry.

For architects and designers, it can reduce the gloss of the panel. And it has the best apparent flatness.

And for manufacturers, it is directional. Meanwhile, it can easily match the surface and repair the weld.

Besides, for the end-user, No.4 can repair the surface to eliminate any damage.

Because the surface of No. 4 is relatively dark, people use No. 4 stainless steel sheets when it is necessary to reduce reflectivity or gloss.

Also, when it is necessary to repair welds and other manufacturing marks to conform to the original surface, the No. 4 stainless steel sheet is also suitable.

Moreover, in restaurants and kitchen equipment, storefronts, and food processing supplies, people also use No. 4 stainless steel sheets.

Meanwhile, it is also widely used in construction and industrial applications. For example handrails.

But of specific types of No.4 stainless steel sheet, people use the 304 No.4 often.

Next, let’s have a look together.

Commonly used 304 No.4 stainless steel sheet

For some parts that need machining, welding, grinding, or polishing, people need stainless steel with good corrosion resistance. At this time, 304 4 good stainless steel sheet is a good choice.

Moreover, in the paper-making and chemical industries as well as low-temperature services, 304 4 stainless steel sheet can be well adapted to these corrosive environments.

In industries such as dairy products and beverages, hygiene and cleanliness are important.

And these industries have widely accepted 304 or 304L No. 4 stainless steel sheets.

Moreover, people can also use this material to make parts for processing acetic acid, nitric acid, and citric acid.

And because it lacks magnetism, it has good tensile, forming, and stamping properties.

When good mechanical properties are required, people often use 304 4 stainless steel sheets.

However, the 304 No. 4 stainless steel sheet is not suitable for high-temperature applications.

Besides,it is not only versatile but also easy to clean.

How to clean when its dirty

No.4 stainless steel sheet can maintain good hygiene. Moreover, even if it is dirty, people can easily clean it.

Next, let me take a look at the cleaning method.

Under normal circumstances, people can use a soft damp cloth to scrub the surface of the No. 4 stainless steel sheet.

And when there is grease on the stainless steel sheet, people can use ammonia or household liquid grease remover to clear it.

However, hot water is also very effective.

And when scrubbing, the surface of No. 4 may not be able to pull out the thread or fluff.

Moreover, it is difficult to remove.

Therefore, people should scrub along the polishing line when scrubbing.

However, people must not use abrasive cleaners.

And it will change the appearance of the No. 4 surface.

If you want to change its appearance, people can choose an inconspicuous small area to try it.

After that, the entire surface is processed.

However, the surface-treated by this method is not uniform.

Besides, there is a white powdery stainless steel cleaner.

And it contains sulfamic acid.

Moreover, people can use it to brighten the surface of No. 4 stainless steel.

Meanwhile, people can also apply light oil on the surface to reduce fingerprints.

Sometimes, the glue on stainless steel will accumulate dust.

And this may cause rapid discoloration or stains on the surface.

At this time, people can wipe it with methyl ethyl ketone or MEK-solvent.

However, the solvent used depends on the way the glue is polymerized.

At this time, one can test other cleaning agents.

cleaning

Conclusion

No.4 stainless steel sheet is a brushed finish.

And it has a darker and uneven appearance.

During the manufacturing process, people use a protective film on the surface to prevent scratches.

Moreover, its roughness is not always the same.

And although Ra can be specified to better control the corrosion performance of the surface, it only has a moderate correlation with the appearance, and it is difficult to repeat the measurement.

Therefore, for important work, it is best to use reference samples viewed under agreed conditions to specify its appearance.

As for its properties, it has good corrosion resistance. However, the corrosion resistance of 2B and BA will be better.

Moreover, it has stretch-ability and form-ability.

Usually, people use it where the reflectivity needs to be reduced.

Moreover, it is widely used in construction, food, kitchen equipment, and other industries.

It also has the advantage that it can meet high hygiene requirements.

And even if it is dirty, people can clean it easily.

For example, people can scrub with a damp cloth.

Moreover, people can also clean them with household cleaners.

Besides, people can choose other cleaning agents according to different stains and purposes.

That’s all for the No.4 stainless steel sheet today.

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