| Why does stainless steel rust also? |
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People will become very surprising when they see the brown spots on the surface
of the stainless steel tubes, for they think the stainless steel won't rust, or ,they will not to be called stainless steel. And there must be something wrong with the steel. In fact, it' a unilateral attitude toward steel. They will also rust under some conditions
Stainless steel can resist oxidation and corrosion in conditions of acid/alkali/salt due to its capability of antirust and antisepsis. And the corrosion resistance can be various depend on the changes of its chemical composing, mutual influence, using conditions and environment. Let's take tube 304 as an example. This kind of material can perform well in the clean dry atmosphere. But when to be placed in the coastal areas where the air contains a lot of salt, it will rust soon. And conversely, the tube 316 will perform well in such kind of atmosphere. So, here comes the conclusion, which is stainless steel will rust and be eroded under some conditions.
The firm thin Cr contained film on the surface of the stainless steel can prevent the oxygen atom from entering, thus enables it the corrosion resistance. But due to some reasons, this kind of film will be destroyed. Then the oxygen atom in the air or liquid will enter into the steel and the iron atom in the steel will be separated to become the ferric oxide to rust the steel surface. And the reasons to cause this are various:
1. There is remained dust which contained other metals on the surface of the steel. And this will form a microcircuit with the cooling water. Then the electrochemical reaction would take place to destroy the film. That is what we called electrochemical corrosion.
2. In the case of water and oxygen, the organic liquid (juice, noodle soup and sputum) on the stainless steel surface will form the organic acid to make the steel rust.
3. The partial corrosion cab be caused by the acid/alkali/salt contained substances remained on the steel surface, like alkali water and limewater used in wall decoration.
4. When reacting with the cooling water, the sulfide, carbon oxide and the nitric oxide is able to form the vitriol, nitric acid and acetum to make the surface rust.
All the things mentioned above can cause rust on the stainless steel. And in order to keep the surface luculent, we give you the advices below:
1. Clean the decorative stainless steel regularly to eliminate the exoteric factors which are able to cause rust.
2. In the coastal areas, it's better to use the material 316 which can resist the seawater corrosion.
3. Some chemical components contained in the material 304 in the market can not achieve the national standard. And the purchasers should be careful when purchasing.
Instructions for construction:
The stainless steel should be used with films on during construction to avoid nicks and dirt. The film bond will also remain on the surface as the time passing. So after remove the film, the surface should be cleaned by using special tools.
Keep the stainless steel away from the magnetic substances or lime. If so, wash it with clean water. And when the construction is finished, we'd better remove the concrete and powders stick on the stainless steel with mild detergent and water..
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| Why does stainless steel magnetic? |
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People always use magnet to check up the quality of the stainless steel. They think those with no magnetism are of good quality, or, it's bad. But, to tell you the truth, this kind of method is not right.
There are many types of stainless steel and they can be classified as following according to their structures in normal temperature:
1. Austenitic stainless steel: 304, 321, 316, 310 etc.
2. Martensitic or Ferritic stainless steel: 430, 420, 410 etc.
The Austenitic stainless steel has no or just weak magnetism. And the Martensitic or Ferritic stainless steel usually has magnetism.
The decorative stainless steel sheets are usually Austenitic 304 with no or weak magnetism. But due to the different processing way or chemical changes during the smelting, the magnetism may be produced. This can not be considered as imposter or reject, but why?
As we mentioned above that the Austenitic stainless steel has no or just weak magnetism and the Martensitic or Ferritic stainless steel usually has magnetism. So if the heat is not proper or the components deviate during the smelting, the Austenitic 304 may contain some Martensitic or Ferritic ones. Thus enables the Austenitic 304 magnetism.
Besides, the cold processing will also turn stainless steel 304 into Martensitic one. The magnetism is in direct ratio with the degree of distortion. So, the magnetism of the stainless tubes76 is smaller than the tube9.5 produced by the same material. And the quadrate tubes are more magnetic than the round ones, especially around the part of angels.
To eliminate the magnetism of the steel 304 caused by the reasons above, we can use the high-temperature solution treatment to resume the austenitic structures.
The things should be stated here is that the steel 304's magnetism caused by the reasons above is different from those maintained by steel 430 or carbon steels. In other words, the 304s magnetism is always weak.
And this information has reminded us that the magnetism is a standard used to classify the types of the stainless steel. The steel 304 and 316 usually have no or just weak magnetism; and those with strong magnetism similar as the carbon steels are not steel 304.
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| Is stainless steel harmful to our health? |
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Stainless steel is a kind of material which can be put into human bodies. And we can find them in most of the fields related with the human health. Nowadays, it is widely used in the food-transit tubes producing, including drinks, dairy products, brewage, medicine etc. And it can also adopt in the field of medical care where material security and cleanness are highly required, like artificial struts, nails, bones, teeth etc. |
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| Can PVD sheets be bent, drawn or embossed without the coating peeling or flaking? |
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| Yes, PVD sheets can be bent greater than 90 degrees without peeling or flaking. The PVD coated sheets can also be drawn or embossed(within limits based on the application)without peeling or flaking. |
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| Can PVD sheet be welded? |
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PVD sheet can be spot welded and laser welded. However the heat from arc or gas welding will discolor the coating. PVD sheet can be soft soldered or low temperature brazed(approximately 600 degrees) without affecting the color.
How do I clean PVD sheet?
PVD sheet can be cleaned with a soft cloth and glass cleaner such as Windex. Soap and water may also be used. Abrasive cleaners such as Comet or polishing compounds can mar the fine PVD finish.
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| How do I prevent scratching the surface during application? |
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Each PVD sheets is covered on the coated side with two layers of low adhesion PVD film. This protects the sheet from damage during bending, forming, cutting and handling.
What is the maximum temperature PVD sheet can be exposed to continuously?
PVD sheets can be exposed to 700 degrees F without changing color. Exposure to higher temperatures tends to darken the color. The degree of darkening will vary depending on temperature variations across the stainless steel.
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| Can I use PVD sheet in high pedestrian traffic areas such as elevators and escalators? |
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| The PVD coating is very hard and resists scratching and marring caused by normal use. However, sharp tools can gouge through the PVD coating. |
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| Do I use usance L/C for payment? |
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| It is acceptable in most cases, however, the issuing bank must be an authorized bank by our company. |
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| What's the difference between the NO.4 240GRITS and 320GRITS? |
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| The hairline produced by 240GRITS is thicker than the 320GRITS's. |
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| Is 1219X2438MM the only size available for the etching finished sheets? |
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| No, we can produce many other sizes according to your needs. Please contact us for more information. |
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| Could etching be processed on the 0.6MM sheets? |
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| The thickness of our Etched sheets range from 0.7MM to 2.0MM. |
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| Does Top Honest produce sizes such as 8inX34in,10inX34in? |
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| Yes, we can produce different size combinations that are best suitable for your applications. Please contact us for more details. |
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| How long will it take for the products to be delivered after ordering? |
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| For export HL and No.4 sheets, delivery (FOB) will normally happen within 20 days. For other products, the manufacturing process will take about 28 days and then FOB ready for shipping. |
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| Were can your products be applied on? |
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| Our stainless steel sheet products can be used in many commercial and industrial sectors and consumer products, please visit our products application page for more details. |
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| How long is the validity of your quotation? |
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| The valid date is stated on your quote. |
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| What's your customary packing? |
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| The wooden and iron cases we use for exports are all of standardized export quality, each case can contain 1.5MT-2.0MT. |
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| What is the maximum temperature PVD sheet can be exposed to continuously? |
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| PVD sheets can be exposed to 700 degrees F without changing color. Exposure to higher temperatures tends to darken the color. The degree of darkening will vary depending on temperature variations across the stainless steel. |
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