Stainless Steel 101

Stainless steel refers to a very broad group of steel alloys consisting of an iron base and a minimum of 10.5% chromium.  The chromium gives the steel its “stainless” properties—essentially corrosion and stain resistance—by forming a very thin, inert chromium-rich oxide layer on the surface of the metal, which prevents the steel from rusting.  The advantage of stainless steels over plated steels is that—if scratched or damaged—the steel will “self-repair” as a new oxide layer is formed.  In plated steels (powder-coated, anodized, etc.), scratches in the plate will often lead to corrosion of the steel underneath.

In general, the higher the percentage of chromium, the stronger the corrosion resistance of the steel.  In addition to chromium, other metals--such as nickel—are added to the mix to give steel particular properties such as strength and malleability.  Nickel, in particular, enhances the above mentioned oxide layer of the steel.  Therefore, the higher the nickel content, the more resistant the stainless steel is to corrosion.

There are several families of stainless steels with different physical properties (atomic structures)--and which vary in quality, durability and temperature resistance based on the percentage of chromium and nickel.  Basic stainless steel has a “ferritic” structure, with high iron content and some chromium.  “Ferritic” steel morphs into “martensitic” stainless with the addition of carbon, which hardens the steel.  Both “ferritic” and “martensitic” stainless steels are magnetic.  Stainless becomes “austenitic” by increasing the chromium content and adding nickel to the mix.  The nickel modifies the physical structure of the steel and makes it both non-magnetic and highly resistant to corrosion.

Because of its strength and corrosion resistance, austenitic steel is the type of stainless most commonly used in the manufacturing of stainless products.  There are numerous grades of stainless within the austenitic family—the two most popular grades being 18/8 (also known as A2) and 18/10 (a.k.a. surgical grade)—known collectively as Type 304, which is part of the 300 series of stainless steel types.  The first number, 18, refers to the amount of chromium present; the second represents the amount of nickel.  Both 18/8 and 18/10 qualify as “food grade”—which mean they are safe to be used in the manufacture of cookware, flatware, and other items used for food preparation and dining.  A second major class of austenitic stainless is the 200 series—also known as low nickel stainless.  200 series stainless is cheaper to produce than 304 because the majority of its nickel content is replaced with manganese (a mineral similar to nickel in terms of oxidation/corrosion protection properties but considerably less expensive).  The 200 series is typically used for stainless steel food containers and--although considered food-safe--is not as resistant to corrosion as 304 Grade and will not last as long.  Both 300 series and 200 series stainless are non-magnetic.

Another type of stainless steel commonly used in cookware, bakeware, kitchenware, and other food prep items is18/0—or Type 430.  Although quite strong and durable, 18/0 contains a negligible amount of nickel (.75%) and therefore has a reduced corrosion/rust resistance.  Unlike the 300 and 200 austenitic series above, 18/0 is ferritic and thus also magnetic.

Safety-minded bird owners will tell you that the tried and true way to tell good quality stainless from bad is the “magnet test”.  If the magnet doesn’t stick, it’s high quality stainless.  If magnetism is detected, then the stainless is not something you want your bird using because it will eventually rust.

The “magnet test” works—for the most part.  What it actually tests is whether or not the stainless is of type austenitic—which is a good thing because austenitic stainless is the quality we want for our birds.  However, as noted above, all types of austenitic stainless are non-magnetic—yet there are some grades of austenitic stainless—notably the 200 series—that you don’t necessarily want your bird to be using for food or play.  Such lower grades of stainless have low nickel content and thus can eventually rust and cause harm to your bird.  Similarly, there are situations when even high quality 304 (18/8 and 18/10) austenitic stainless will fail the “magnet test”.  Spinning or cold working the stainless during the manufacturing process can introduce weak magnetism into the material.  Such is the case with the spun 18/10 stainless Wingdow® uses for the trays and cones on its Unipod stands, as well as some of the stainless fasteners we use that are cold worked.  So, the “magnet test”, while helpful, is not a foolproof test of stainless quality. 

The best way to ensure you are getting good quality stainless for your bird is simply to ask the manufacturer about the type of stainless used to make your product.  A reputable manufacturer will be able to provide you with that information—and most will have some form of documentation certifying stainless grade.  If asking the manufacturer is not an option, at least try and determine the country of origin for your stainless item, since that’s often a good clue about the quality you can expect.

Wingdow® uses only American-made 18/10 and 18/8 stainless for all of our products—for the simple reason that “we know what we’re getting”. 

Stainless is not the same everywhere in the world.  Different countries have different standards dictating the composition and quality of the various grades of stainless steel.  So, what we recognize as high quality, Type 304 stainless in the US might not be quite the same as a comparable 304 grade produced in Asia or elsewhere.  Similarly, different countries have different regulations concerning the manufacture of metals--and goods in general.  Regulatory agencies in the US are well established and do a good job of policing quality of American-made goods.  This is not always the case in developing economies, where the emphasis is on “cheap” production and where reports of defective and unsafe goods abound.  

Resource availability is also a factor.  Both the US and Canada have large deposits of both chromite and nickel—two key minerals that go into the making of stainless—so American stainless manufacturers have more than enough domestic supply for their needs. Not so in some other countries like China, where domestic reserves of these metals are small and/or undeveloped—and where temptation exists to add more readily available (and potentially unsafe) metals to imported chromite and nickel as a way to contain costs.   This is not to say that all Asian-made stainless is suspect.  There are many quality conscious manufacturers in that part of the world--producing quality stainless-based goods.  But—this also begs the question “how do you know?”  If the FDA and other US governmental agencies can’t catch all the unsafe goods and materials brought into this country—how are small companies like Wingdow® supposed to know when something is not up to standard?  So—for Wingdow® at least—“buying American” is the safest bet.