Here are the key factors when considering to buy stainless steel coils according to your need:
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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.
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.
If you want to learn more, please visit our website Stainless Steel Cold Rolled Coils.
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.
When it comes to metalforming, few materials offer the versatility, strength, and formability of stainless steel strip coil. But if you’re an engineer or procurement lead sourcing metal for critical stamped or deep-drawn parts, you already know that not all coil is created equal.
At Ulbrich, we’ve spent a century rolling, refining, and rerolling precision strip products for some of the most demanding industries in the world. We’ve learned that high-performing parts start with high-quality coil, and high-quality coil starts with clarity. Clarity around what’s inside the metal, how it’s made, and how well it fits your tooling, press, and process.
Let’s start by demystifying the most common stainless steel coil grades you’ll encounter and how to choose the right one for your application.
The phrase “stainless steel coil” might sound simple. But behind it lies a complex landscape of metallurgical grades, each engineered with specific alloying elements, processing histories, and performance profiles. In metalforming, choosing the right grade is about matching metallurgical properties to real-world forming conditions.
The best way to determine the right stainless steel for an application is not by choosing the material first, but by understanding the demands of the part. Factors such as draw depth, acceptable springback, and surface finish requirements all play a critical role in identifying the ideal alloy and temper. Ulbrich’s technical team supports customers throughout this process, helping them weigh tradeoffs and select the best option for their forming and end-use requirements.
Here’s a breakdown of the most common grades used in stamping, deep draw, and hydroforming, along with the tradeoffs and considerations that come with each.
Often referred to as the “18-8” alloy (for its 18% chromium and 8% nickel content), 304 stainless steel is the go-to choice for applications that demand excellent formability and corrosion resistance. It strikes a balance that’s ideal for most moderate-depth draws and compound geometries.
The low-carbon variant, 304L, minimizes carbide precipitation during welding which is critical for drawn parts that require secondary weldments or assemblies.
When to choose it:
316 picks up right where 304 leaves off. By adding molybdenum to the base alloy, 316 offers enhanced resistance to chlorides and aggressive environments, like those in marine, medical, or chemical applications.
The tradeoff? It’s a bit more expensive, and its work-hardening rate may require dialing in your press forces or tooling clearances.
When to choose it:
If you'd like to learn more about when to use 304 vs 316 stainless steel, check out this article.
As a ferritic stainless steel, 430 lacks nickel which lowers cost, improves polishability, and delivers magnetic properties. It doesn’t offer the same ductility or corrosion resistance as austenitic grades, but for shallow draws and cosmetic trim, it’s often the ideal choice.
When to choose it:
By substituting manganese for some of the nickel in 304, 201 series stainless delivers similar strength and corrosion resistance but often at a lower cost. That said, these grades can work-harden more aggressively, making them trickier to form without proper process control.
When to choose it:
For components that require long-term elastic performance, think constant force springs or surgical clips, precipitation hardening stainless like 17-7PH can be cold worked and heat treated to provide high strength and stability under load.
When to choose it:
Before it becomes coil, steel begins as a rough, heavy, and unformed slab. But through a sequence of thermomechanical processes, that raw steel evolves into a precisely engineered strip coil, ready to meet the demands of complex forming operations.
Yet not all coil takes the same journey. And for precision metalforming operations like stamping, deep draw, or hydroforming, the how behind coil production can matter as much as the what.
Here’s what you need to know about how stainless steel coil is made and why it matters to your bottom line.
The process begins at the melt shop, where alloying elements like chromium, nickel, molybdenum, and manganese are added to molten steel to create the desired stainless grade. Once cast into slabs, the material is hot rolled—that is, passed through heavy rollers at temperatures above °F. This reduces the slab’s thickness while elongating it into a coilable strip.
The resulting material is the first hot-rolled coil, typically with a rough, oxide-laden surface. It’s thick (often 0.100" or more), and while suitable for some structural applications, it’s not ready for fine-tolerance forming.
Before moving on to cold rolling, the hot-rolled coil of steel undergoes pickling; a chemical bath (usually nitric-hydrofluoric acid) that removes the mill scale and prepares the surface for downstream processing.
At this point, some mills might sell the coil as "hot-rolled, pickled, and oiled" (HRPO), but for high-precision applications, it's only halfway there.
Cold rolling takes place at ambient temperatures using high-pressure rollers—sometimes in multiple passes—to refine the material’s thickness, flatness, and grain structure. This process dramatically improves dimensional control and work-hardens the metal, increasing its strength and consistency.
Many manufacturers stop here. But if you're building parts that can’t afford to fail, you need something more.
Many manufacturers stop after cold rolling (and annealing) to produce standard tempers. But if you're building parts that can’t afford to fail, you need the tight tolerances and property control offered by precision rerolling.
This is where Ulbrich enters the picture. Precision rerolling takes cold-rolled stainless steel and enhances it even further—tightening both dimensional tolerances and mechanical property windows to levels that commodity mills can’t consistently reach.
Using specialized cluster mills and in-line measurement systems, Ulbrich can achieve:
Most mills report tolerances based on “centerline” samples. Ulbrich’s rerolling process ensures that those tolerances are held across the entire width and length of the coil, because real parts aren’t made from samples, they’re made from every inch of the coil.
Between cold rolling passes, coils may be annealed: a heat treatment that softens the metal and restores ductility. For deep draw applications, this balance between strength and elongation is crucial.
Then comes slitting, where master coils are cut into narrower widths that match customer requirements. Whether you need a 24-inch-wide pancake coil for large panel work or a .125-inch oscillate-wound strip for high-speed stamping, this is where form factors are tailored to the job.
When you’re sourcing stainless steel coil, it’s easy to focus on price, grade, and lead time. But in practice, your material’s form, dimensional tolerance, and mechanical profile will have far greater impact on your team’s success.
A coil that’s technically the right alloy but arrives in the wrong form, with inconsistent thickness or unpredictable yield strength can grind production to a halt. That’s why precision stamping and deep draw manufacturers are increasingly demanding not just “steel coil,” but coil engineered for their exact process conditions.
Let’s unpack what that means, starting with coil form.
The way your coil stainless steel is wound, protected, and delivered isn’t just about logistics. It affects line speed, operator safety, tool wear, and how often you need to stop the press.
The industry standard for decades, pancake, or ribbon wound, coils are flat wound and loaded vertically. They’re simple to handle and ideal for low to mid-volume jobs. But in high-speed operations, frequent coil changes can become a productivity bottleneck.
Ideal for:
Imagine a roll of sewing thread—that’s oscillate winding. By side-winding strip laterally onto a spool, you can combine several coils’ worth of material into a single, continuous reel. This minimizes downtime, eliminates press stops, and can reduce scrap caused by feed restarts.
Ideal for:
Switching to oscillate coil can increase throughput by 15–30%, simply by cutting downtime. Ulbrich’s team helps customers evaluate ROI on form changes and can advise on decoiler compatibility.
Mostly used in fine wire and ultra-narrow strip (<0.100”), traverse wound coil zigzags back and forth across a spool like a fishing reel. It’s an elegant solution for delicate material that needs to feed smoothly without kinks.
Ideal for:
If you're confused about the difference between a ribbon-wound pancake coil and an oscillating or traverse-wound coil, check out this article.
Even within spec, slight variations in thickness or width can wreak havoc on a forming process. A coil that’s 0.001" too thick at one end can cause galling, increased tonnage, or premature die wear. Too thin, and your part might tear or wrinkle.
⚠️ Pro tip: Always ask a supplier if they can hold tolerance across the entire coil—not just certify that a few test strips were within spec. That’s the difference between real precision and paperwork precision.
In stamping and deep draw, the “feel” of the metal matters. How it bends, flows, springs back, or resists tearing is governed by the metal’s mechanical properties, which must be controlled, not assumed.
The key metrics here include:
When mechanicals vary from coil to coil, you lose control of part performance. You might crack on one run and wrinkle on the next. But with rerolled strip tuned to your die and draw depth, you get:
Ulbrich achieves this not by guessing, but by working backwards from your part’s needs. We study your geometry, press forces, and forming limits, then engineer a strip coil with the exact properties to get you there, every time.
In forming operations, tolerance stacks. You’re not just dealing with coil variability; you’re combining that with die clearance, press repeatability, feed alignment, and more. The tighter your coil tolerance, the more breathing room you give your tooling.
Think of it like this:
At Ulbrich, we don’t treat coil as a commodity. We treat it as a critical input that allows stamping and deep draw teams to hit their goals, protect their tools, and meet production targets without second-guessing their material.
Are you interested in learning more about Steel Cold Rolled Coil? Contact us today to secure an expert consultation!