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Stainless Steel – A Deeper Look

What Is Stainless Steel and Why Is it Stainless?

So you’re thinking of purchasing a Stainless Steel grill, are ya? Before you do, be sure to peruse our blog post on the very subject – Stainless Steel Grill: Truth or Consequences?  For all you more inquisitive engineering-minded and metallurgic-ally inclined, we’ve pulled together a bit of history of this great material that has the grilling manufacturing world in  a frenzy.

Stainless Steel: A Brief History

In 1913, English metallurgist Harry Brearly, working on a project to improve rifle barrels, accidentally discovered that adding chromium to low-carbon steel gives it stain resistance. In addition to iron, carbon, and chromium, modern stainless steel may also contain other elements, such as nickel, niobium, molybdenum, and titanium. Nickel, molybdenum, niobium, and chromium enhance the corrosion resistance of stainless steel.

Chromium as Stainless Steel Grill element - GrillJunkie

It is the addition of a minimum of 12% chromium to the steel that makes it resist rust, or stain ‘less’ than other types of steel. The chromium in the steel combines with oxygen in the atmosphere to form a thin, invisible layer of chrome-containing oxide, called the passive film. The sizes of chromium atoms and their oxides are similar, so they pack neatly together on the surface of the metal, forming a stable layer only a few atoms thick.

If the metal is cut or scratched and the passive film is disrupted, more oxide will quickly form and recover the exposed surface, protecting it from oxidative corrosion. (Iron, on the other hand, rusts quickly because atomic iron is much smaller than its oxide, so the oxide forms a loose rather than tightly-packed layer and flakes away.) The passive film requires oxygen to self-repair, so stainless steels have poor corrosion resistance in low-oxygen and poor circulation environments. In seawater, chlorides from the salt will attack and destroy the passive film more quickly than it can be repaired in a low oxygen environment.

Types of Stainless Steel

The three main types of stainless steels are austenitic, ferritic, and martensitic. These three types of steels are identified by their micro-structure or predominant crystal phase.Types of Stainless Steel - GrillJunkie

Austenitic Stainless Steel:

Austenitic steels have austenite as their primary phase (face centered cubic crystal). These are alloys containing chromium and nickel (sometimes manganese and nitrogen), structured around the Type 302 composition of iron, 18% chromium, and 8% nickel. Austenitic steels are not hardenable by heat treatment. The most familiar stainless steel is probably Type 304, sometimes called T304 or simply 304. Type 304 surgical stainless steel is an austenitic steel containing 18-20% chromium and 8-10% nickel.

Ferritic Stainless Steel:

Ferritic steels have ferrite (body centered cubic crystal) as their main phase. These steels contain iron and chromium, based on the Type 430 composition of 17% chromium. Ferritic steel is less ductile than austenitic steel and is not hard-enable by heat treatment.

Stainless Steel Grills - GrillJunkieMartensitic Stainless Steel:

The characteristic orthorhombic martensite microstructure was first observed by German microscopist Adolf Martens around 1890. Martensitic steels are low carbon steels built around the Type 410 composition of iron, 12% chromium, and 0.12% carbon. They may be tempered and hardened. Martensite gives steel great hardness, but it also reduces its toughness and makes it brittle, so few steels are fully hardened.

There are also other grades of stainless steels, such as precipitation-hardened, duplex, and cast stainless steels. Stainless steel can be produced in a variety of finishes and textures and can be tinted over a broad spectrum of colors.

 What to Look For in a Stainless Steel Grill?

Stainless Steel is a popular choice for grills and smokers. Two types of stainless are used in the manufacture of Grills and BBQ cookers: Austenitic and ferritic. The boys over at Amazing Ribs do an excellent job describing the difference between the types of Stainless Steel.

Stainless Steel Grill on GrillJunkie blogIn essence, what they state is because it contains more nickel and less steel in the alloy, 304 is higher quality and higher cost. 430 is not as durable and it is harder to weld properly. 430 contains more steel and magnets stick to it. 304 will not attract magnets. But don’t bother bringing magnets to a big box store on your next shopping trip. Most grills are 430 with the exception of some burners and grates. Only the most expensive cookers use 304 extensively. Even Weber has stopped using it.

The most significant problem with cheap grills is they often use very thin 430 stainless. These lightweight machines are pretty and shiny on the showroom floor but vulnerable to the demands of grilling. They can quickly develop minute stress fractures that lead to corrosion and reduced performance. They also lose their shine quickly and need polishing to maintain their sexy showroom look.Stainless Steel Grill via GrillJunkie blog

Don’t be afraid of 430, it does not deserve the derision common on the internet, but do look for heavy gauge construction throughout. Look at the screws, because sometimes they are not stainless and they will rust. Be advised that some manufacturers use heavier gauge steel on the lid and only the lid. They know it is one of the first things you will touch and a heavy lid creates a good first impression. They may even use 304 on the lid and 430 on the cart.

If you are chosing between stainless and other materials, select in favor of thickness. Thick powder coated steel or enameled steel will retain heat better than thin stainless and if properly coated, they will not rust. And coated steel is cheaper than stainless.

What are your thoughts on this GrillJunkie blog post? What Fires YOU Up?We welcome your comments, healthy debate, and the inevitable disagreement. Leave a reply or comment. It’s OK. Bring it on!

 

Comments ( 3 )

  1. ReplyGrillJunkie - Addiction to Grilling | That Stainless Steel Grill: Truth or Consequences?

    The term stainless steel is one of those deceptive grilling and BBQ phrases which can cause both mass hysteria and widespread confusion.

  2. ReplyEvelyn Kalmer

    Today there are many various types of stainless steel materials in the market. As consumers we need to know the kind of its type and function so as to suit our needs.

  3. ReplyWAYLON

    Our Game Day grills are American made from 304 grade stainless steel materials, including cast stainless steel burners. Both the 36 and 42 models are road-ready!

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