Comparing these two common, versatile stainless steel grades
There are many different grades of stainless steel on the market. It can be confusing for a non-metallurgist to know what alloys are best for what applications. Previous posts have talked about 304 stainless (common in kitchens), 316 stainless (marine grade), and 409 stainless (popular in car exhausts). For those buying barbeques, however, the choice of stainless used is often 304 vs. 430. (430 is also used for various truck parts.)
For many home cooks, this stainless is decorative or protective and used on visible metal surfaces, rather than on cooking surfaces themselves. For cost efficiency, enameled iron is common, wherever looks are not a primary issue.
Why are 304 and 430 used for barbeques?
Steel is prized for its strength and mechanical properties. It is created when iron is mixed with carbon. Stainless steels also include chromium, which provides a surface-protecting layer, in a process called “passivation.” Passivation helps maintain stainless steel’s shiny, silver finish.
The ratio of these elements, as well as additions to the mix like molybdenum, nickel, or copper, change the mechanical properties of the metal.
304 stainless steel is the most common commercial-grade alloy. It is also known as 18/8 because it contains around 18% chromium and 8% nickel. 430 stainless steel is less expensive because it does not contain nickel.
These two alloys are chosen for grills and barbeques for a few reasons. They both are food-safe because of their corrosion resistance: in acidic environments, the 430 is slightly more vulnerable to corrosion, but only with prolonged exposure. Both alloys resist rusting in the wet conditions that might be found on a backyard patio.
Importantly, they both are durable at the temperatures involved in food preparation.
These alloys are also chosen by manufacturers for how easy they are to work with. The metallurgist evaluating a BBQ design will look at the strengths and weaknesses of these alloys that will help determine ease-of-production.
What are the differences between 304 and 430 stainless steel?
The addition of nickel into 304 stainless means it preserves an “austenitic” molecule, common in molten steel, when it is at room temperature. This microstructure produces 304’s material properties. Austenitic materials are formable, weldable, resilient even at cryogenic temperatures, and are highly corrosion resistant.
In comparison, the 400-series of stainless steels are all ferritic steels. These are less formable, less weldable, and don’t do well at cryogenic temperatures. Still, some types, like the 430, have excellent corrosion resistance and are very heat tolerant.
Excellent, although other alloys may be used if resistance is needed for very salty conditions
Excellent, although other alloys may be used in very acidic or very salty conditions
Hardens during cold-working
Formability / Ductility
Machinable (when annealed)
High temperature resistance
Maximum intermittent service temp
The 304’s strengths mean that it’s used in many applications requiring cold resilience or high ductility, but the nickel increases the overall cost of the material compared to 430. The relative cost of these steels fluctuates with market conditions and spec, but the price of 430 to the manufacturer is often 55-75% that of 304.
In many cases with backyard barbeques, these extra material properties of 304 may be unnecessary. Usually, BBQ grills don’t need to manage cryogenic temperatures. With some designs, formability and weldability are not necessary. When homeowners are primarily looking for corrosion resistance, 430 might be as good as 304.
But some designs require formability and weldability: 304 is the clear winner in these categories. On the other hand, 430 is slightly less challenging to machine than 304. Therefore, price, design and what manufacturing specialties a vendor has all factor into the choice of alloy.
Seeing the difference in the two alloys, it’s clear that for many backyard barbeques will be well served by 430. It offers the corrosion resistance and material strength necessary for this application. One important consideration is that home locations are less likely to be exposed to brine or acidic liquids for hours every day compared to a commercial kitchen.
A more telling factor for the home chef is how well constructed the grill is overall. How thick is the stainless steel? How finished is the surface? Look for heavy gauge metal, not just in the lid but also in the ledges and façade. Additionally, look for a fine finish on the surface: if it is rough or uneven to the touch, it will be more likely to experience crevice corrosion. Thin gauge rough-finished 304 stainless on a shoddily-made grill will have a shorter life than a well-constructed barbeque made with thick 430.
However, if the barbeque is going to get near-commercial use, or if the looked-for design of the barbeque is welded and formed, then 304 might be a cost worth paying.
The stainless steel magnet test
A common piece of advice is to use a magnet to determine the type of stainless steel used on a barbeque. Austenitic stainless steels, like 304, are non-magnetic, which is why some fridges and dishwashers won’t hold a kitchen magnet. In comparison, the ferritic 430 stainless steel is magnetic. Stainless knives are often made of 400 series metals, which is why they can be stored on a knife strip.
Since material specifications often only say “stainless steel,” rather than mentioning the grade, savvy shoppers will sometimes bring a magnet to test what they’re getting.
A word of caution: the magnet test can be tricked by the use of 202 and 201 alloys. These do not have the excellent corrosion resistance of 430. However, 201 and 202 are both non-magnetic when annealed, so they can surprise a buyer into thinking they’re getting 304 stainless at a very good price. It would be almost impossible for a buyer to differentiate in the showroom. 201 and 202 would be more vulnerable to developing rust in the ambient moisture of the backyard.
Well known grill companies, especially those offering comprehensive warranties, are generally not using 201 or 202 stainless. It’s wise to go with a reputable manufacturer or one offering a good, comprehensive warranty.
Maintaining your stainless steel
A lot can be done to maintain stainless steel of either grade. A badly treated 304 will not look better than a well-treated 430.
Certain metals can be hazardous to stainless. Iron deposits interrupt the passivation layer on stainless steel, so steel wool or steel-bristled brushes should never be used on or near it. Installing with steel tools is also a no-no. If steel and stainless collide, give the stainless steel a quick wash with soap and water, followed by a clean water rinse. Specialized stainless steel cleaners can also be bought that help maintain the passive layer.
Aluminum screws or other small can create a problem called “galvanic corrosion.” If you are assembling a grill with stainless steel components, do not sub out the screws that come with the kit for aluminum ones. Be wary also of aluminum carabiners or other accessories that are likely to permanently sit or hang from the stainless. When wet, they will lead to faster staining of the stainless.
Most of the time, routine care will involve simple soap and water washes. Bleach, chloride, or abrasive cleaners are not recommended.
Special cases including food staining, localized rust, oil and grease, and burnt on stains can be found on our Cleaning Stainless blog.
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