Here are the key factors when considering to buy stainless steel coils according to your need:
For stainless steel products, the installation environment is a key factor.
When choosing stainless steel, we mainly consider the atmospheric conditions, the concentration levels of particular chemicals, and the acid.
If the installation environment is less corrosive, an austenitic stainless steel grade for general purpose is suitable. While, for a highly acidic environment, you need to choose a stainless steel grade like 316, 904L, or .
The temperature of the environment is also an important factor.
In the furnace environment(900-C), the high temperatures will speed up the corrosion of stainless steel.
Also, it puts extra pressure on stainless steel products.
So, if the temperature is always high, you need the well heat-resistant stainless steel, such as 321 and 253MA.
Very low temperature is another factor. Austenitic stainless steels are effective at very low temperatures.
They maintain a higher tensile strength at low temperatures than at ambient temperatures.
Despite a slight degrading of toughness, these steels work well in temperatures as low as -161°C.
Austenitic grades have a low magnetic response.
Those with higher nickel content are not magnetic under any conditions, such as the 316 or 310 grades.
And the ferritic and martensitic stainless steel grades (400 series) are highly permeable.
Moreover, duplex grades like and are also ferromagnetic.
Steel strength is an important factor to consider before you choose the grade, but it is a complex one.
Your requirements for stainless steel depending on the purpose and the installation environment.
In some cases, high strength stainless steels, like austenitic and duplex, are suitable. But in some cases, their disadvantages are also obvious and do not meet your requirements.
For example, high strength austenitic steels produced by work hardening are not suitable for welding. It makes the steels soft.
Stainless steel products come in many forms, such as sheets, bars, and tubes.
The form will affect the grade you need.
Not all grades have all product forms and sizes. Austenitic stainless steels are very versatile.
You can find products in a wide variety of forms and sizes for different purposes. Ferritic steels generally appear in sheet form. And martensitic steels are common in solid bar form.
When installing stainless steel products, there may be some special requirements.
As a result, you may need to change the grade of steel.
For example, you may want non-magnetic steel, need products that are suitable for welding or products with a high degree of forming. Or simply you just want a good-looking product.
Cost is always a factor when choosing to buy stainless steel coil.
And you need to balance it with all the other considerations. Sometimes the best technical steel is too expensive.
But please remember to assess the cost on a life cycle basis.
Do not look at the initial price only then overlook the life cycle. Stainless steel products have a long life, so a high cost for high-quality steel is reasonable.
As long as the quality is good enough, stainless steel is one of the safest materials.
But remember, the quality matters.
So, how do you know if the stainless steel coil you've got is good or not? Try out the below methods.
The theory of the 'magnet test' is a rumour.
It tells you that you can test the quality of stainless steel with a magnet.
But the fact is that the magnet is to test whether the steel is austenitic, or whether the steel contains chromium and nickel.
There are three main types of structures in stainless steel: austenite, ferrite, and martensite.
When you see stainless steel with 18/8 or 18/10 marks, it tells you the amount of chromium and nickel.
So, both 18/8 and 18/10 are austenitic.
The 'magnet test' is useful when you use it in the right way. And it's easy to do by simply taking a magnet to your stainless steel coil.
If the magnet sticks, the coil is safe because it indicates no nickel in the steel. But if the magnet doesn't stick, it means the steel contains nickel, so the coil is not safe for food usage.
This test is credible.
If a magnet is to stick to steel, it is not a nickel (austenitic) alloy.
There is a problem with this theory, however.
First of all, there are no stainless steel pans with magnetic inside and outside. It's very difficult to find a fully magnetic stainless steel coil on the market.
That's not surprising. The reason is that austenitic stainless steel which contains nickel is highly resistant to corrosion.
Corrosion resistance is very important to buy stainless steel coil, isn't it?
If the coil is fully magnetic stainless steel, it would corrode and not last very long. Without nickel, the metal is not stable.
For this reason, it's not necessary to buy stainless steel coils that are magnetic, nickel-free.
You will find magnetic stainless steel in the outer layer of some quality stainless steel.
It's to make the coil compatible with induction stovetops in case you need it for cookware. The reason is, induction stovetops use an electromagnetic field to heat the cookware.
So, high-quality stainless steel cookware usually has three layers of metal. The interior is austenite stainless steel. The exterior is ferrite stainless steel. And the middle layer is aluminium.
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It's for good heat conductivity because steel itself does not conduct heat evenly. Stainless steel of poor quality usually has only one austenitic layer.
But there is still a difference in quality between different types of austenitic stainless steel.
Sometimes you will find that austenitic stainless steel is less magnetic. That's because, during manufacturing, the steel is cold-processed to form ferrite and martensite.
This process makes it easier to corrode and leach.
The formulation of austenitic stainless steel cookware is careful to avoid this. And the result is a very stable austenitic alloy that resists corrosion and leaching of the metal.
So, A carefully-formed, highly-stable, non-corrosive, and nickel-containing stainless steel is safer than a pure magnetic stainless steel.
Pure magnetic stainless steel will break down and corrode over time. And it doesn't even exist in the market!
To be honest, it's hard to know whether your stainless steel is of the best quality unless you are a metal expert. Or unless you go to the factory and see how it's made. Otherwise, you won't know whether your stainless steel has corrosive materials.
Your best choice is to buy high-quality stainless steel from the start, choose a brand with a good reputation for quality, such as WJH premium stainless steel.
But still, there's another way for you to determine whether the stainless steel coils you've got is potentially harmful.
What is all this stuff? They are the types/grades of stainless steel. No worries. We'll tell you in detail in the following section after this.
Now let's focus on how to make use of the tester.
316 stainless steel is an austenitic alloy known for its remarkable corrosion resistance and mechanical strength.
The "316" designation refers to its specific chemical composition and performance standards under ASTM.
As austenitic steel, 316 features a face-centered cubic crystal structure, providing excellent toughness and ductility. With proper maintenance, it can last decades'often longer than a human lifespan!
The chemical composition of 316 stainless steel includes iron (Fe), chromium (Cr), nickel (Ni), and molybdenum (Mo), with possible traces of manganese (Mn), silicon (Si), carbon (C), phosphorus (P), and sulfur (S). The specific composition range is as follows:
Although 316 stainless steel has excellent corrosion resistance and mechanical properties due to its high chromium and nickel content, it is still classified as an iron-based alloy, as iron is its primary component (the largest proportion).
316 stainless steel can be identified through methods such as magnetic testing. It is generally non-magnetic in its annealed state but may exhibit slight magnetism after cold working. Spectroscopic tools can also verify its composition to confirm that it meets 316 standards.
316 is an austenitic alloy offering superior corrosion resistance, while 416 is martensitic, focusing on machinability but sacrificing corrosion resistance.
18-8 (commonly 304) and 316 are similar, but 316 contains molybdenum, offering enhanced resistance to chemicals and saltwater. For general use, go with 18-8; for harsh conditions, choose 316.
Both grades have comparable hardness, but 316 excels in highly corrosive environments due to its molybdenum content. It is also more expensive than 304.
Chemical analysis methods, such as alloy analyzers or molybdenum point tests, can identify 316 stainless steel due to its molybdenum content.
Certification markings are another reliable reference.
Typically, 18-8 and 18-10 both refer to 304 stainless steel, where '18' represents 18% chromium and '8' or '10' refers to the percentage of nickel (8% for 18-8, and 10% for 18-10).
Though 18-10 is more commonly associated with 304 stainless steel, some 316 stainless steel products, particularly in cookware, may also be labeled as 18-10.
However, 316 stainless steel also contains molybdenum, which is not reflected in the 18-8 or 18-10 designation.
No, A2 commonly refers to 304 stainless steel in fastener classifications, while A4 corresponds to 316.
Grades like 317, 904L, and duplex stainless steels (e.g., ) surpass 316 in specific aspects, particularly for extreme corrosion resistance.
303 stainless steel has added sulfur, enhancing machinability, but it sacrifices some corrosion resistance compared to 316.
Use 303 for components like screws, bolts, and precision parts that require high machinability.
In contrast, choose 316 for environments with high exposure to moisture, saltwater, or chemicals.
305 stainless steel is optimized for deep drawing applications, making it ideal for products like kitchenware and appliance housings.
316, however, is better suited for use in acidic or chloride-rich environments, such as chemical processing equipment or marine components, due to its superior corrosion resistance.
306 is not a recognized stainless steel grade under international standards and lacks standardized composition or performance data.
On the other hand, 316 is a well-documented grade with established specifications in both AISI and SUS classifications.
This makes 316 the preferred choice for applications requiring reliable corrosion resistance and mechanical properties, such as medical devices and marine engineering.
308 stainless steel is commonly used as a filler material for welding, especially for joining 304 stainless steel.
316, however, is typically used as a base material in applications demanding superior corrosion resistance, such as food processing equipment and chemical storage tanks.
316 is an austenitic grade offering excellent corrosion resistance, particularly for marine and pharmaceutical applications.
Conversely, 410 is martensitic, providing higher hardness and wear resistance but lower corrosion resistance.
Choose 410 for high-strength, wear-resistant tools and components, and 316 for environments with exposure to corrosive agents.
904L, with its higher alloy content, including copper, provides superior resistance to acids and chlorides, making it suitable for highly corrosive environments like acid chemical plants and luxury watchmaking.
316, on the other hand, is ideal for moderately corrosive conditions and offers a better cost-to-performance ratio.
316L has a lower carbon content than 316, reducing the risk of carbide precipitation during welding and making it ideal for welded structures such as pressure vessels and piping systems.
316 is a good choice for applications requiring general corrosion resistance and mechanical strength without extensive welding.
A-286 is a high-temperature, high-strength alloy primarily used in aerospace and industrial applications requiring excellent mechanical properties at elevated temperatures.
316 focuses on corrosion resistance, making it better suited for environments with exposure to moisture, salt, or chemicals.
Yes, you can mix 304 and 316 stainless steel.
However, in harsh environments, this combination might lead to galvanic corrosion, as 304 lacks molybdenum.
Mixing is not recommended for critical applications where corrosion resistance is crucial.
This refers to 316 stainless steel alloyed with titanium to enhance corrosion resistance and weldability further.
The addition of titanium improves its stability against carbide precipitation during welding and increases its durability in high-temperature environments.
If you want to learn more, please visit our website Stainless Steel Sheet Coil.