When selecting stainless steel for your application, you’ll encounter two of the most common grades: type 430 and 304. But what’s the difference between these two varieties, and how do you determine which is better for your particular project? This guide will cover everything you need to know to choose the best grade for your needs.

What do the different grades of steel signify?

Steel grades are far more than just numbers and letters. They are the steel industry’s methodology for ensuring consistency and communicating quality. Grade specifications allow manufacturers to achieve precision processing and performance repeatability. Each grade indicates the factors that make that specific steel unique – its chemical composition, strength, workability, and more. Grades provide the metal language that engineers, metallurgists, and designers use to match the optimal steel variety to the application. They bring order and meaning to the wonderful but complex world of steel.

What is 430 stainless steel?

With 16-18% chromium and less than 0.75% nickel, grade 430 stainless steel is respected for its corrosion resistance and decorative appeal. Don’t let its matte grayish finish fool you – this alloy has a minimum yield strength of 30 ksi and tensile strength of 65 ksi.

Its higher carbon content does make it slightly more challenging to weld, but creates no roadblocks for bending or drawing it into shapes. And while it may not be the best for outdoor applications it’s ideal for indoors where aesthetics matter more than brute weather-resitant strength. Well looked after 430 stainless steel will stand the test of time.

What is 304 stainless steel?

With its iconic austenitic structure, grade 304 stainless steel is the variety engineers ask for by name. Its chromium and nickel content of 17.5-19.5% and 8-10.5% respectively give 304 excellent corrosion resistance and durability, perfect for outdoor applications.

With a minimum yield strength of 30 ksi and tensile strength of 75 ksi, this alloy has the strength to match its reputation. 304 lives up to its nickname of “18/8 stainless” by being exceptionally weldable and formable. Press it, stretch it, bend it, weld it – 304 can handle it all with ease. Its versatility, combined with corrosion resistance, makes 304 the go-to choice for kitchen equipment, industrial applications, and far beyond. When you need reliable stainless steel in quantities, large or small, 304 delivers the goods.

Its strong and non-magnetic properties ensure durability and functionality in outdoor conditions, especially in saltwater environments. Plus, it delivers that enviable chrome-like mirror finish, ideal for elevating the look of your outdoor kitchen. So, if you’re seeking a stainless steel that can handle the great outdoors with style and resilience, grade 304 is the clear winner for your outdoor range hood.

Key Characteristics of 430 and 304 Stainless Steel 

While both 430 and 304 stainless steel contain iron, chromium, manganese, silicon, carbon, phosphorus, and sulfur, their composition percentages vary:

The key differences stem from 304 containing nickel while 430 does not. The nickel gives 304 greater corrosion resistance, ductility, and strength.

Corrosion Resistance

One of the main reasons stainless steel is used is its ability to resist rust and corrosion. 430 does great with cooking exhaust inside but isn’t ideal for use outside.

304 stainless steel has greater corrosion resistance than 430 due to its nickel content. It maintains this corrosion resistance in temperatures up to 870°C. 430 stainless steel begins to oxidize rapidly over 425°C.

304 can withstand corrosion from:
Salt water and saline environments Acids, including reducing acids like hydrochloric and sulfuric acid Alkaline solutions Various organic acids like citric or acetic acid

430’s lower chromium content means it may corrode in harsh environments like the outdoors. It’s more suited for dry, mildly corrosive conditions rather than wet or acidic ones. It does great inside.

Strength and Hardness

The nickel in 304 makes it stronger and harder than 430 stainless steel. 304 has a tensile strength of 505 MPa compared to 430’s 485 MPa. The hardness of 304 and 430 stainless steel is 150 and 85 on the Vickers scale, respectively.

304 can be rolled or formed into thinner gauges than 430 without loss of strength. Its increased hardness also gives it better dent and abrasion resistance compared to 430.

And don’t underestimate the value of 430 stainless steel. With a tensile strength of 485 MPa and a Vickers hardness of 85, it still offers robust durability and resistance. Plus, 430 can be efficiently formed into various shapes and maintains solid dent and abrasion resistance, making it a reliable choice for your cooking space.

Ductility and Machinability

304 stainless steel is more ductile than 430 due to its nickel content. This gives it better formability, allowing it to be drawn into thin wires or deep drawn into custom shapes. 430 is more brittle and subject to cracking during forming.

The machining characteristics of the two steels also vary. 304 produces discontinuous chips during machining, which helps avoid chip packing and build-up on tooling. 430’s continuous chip formation leads to more tool wear.

Overall, 304 has better machinability than 430, which doesn’t mean a lot to customers who purchase our hoods, but for those inquiring minds that want to know…

Magnetism

430 stainless steel is ferromagnetic, meaning it’s strongly attracted to magnets and can be magnetized. 304 stainless steel is non-magnetic because its austenitic structure doesn’t allow magnetic domains to form.

This makes 304 useful for applications where magnetic properties are problematic, like MRI machines, scientific instruments, and kitchen appliances where magnetism can affect food flavors. 430’s magnetism makes it suited for holding doors open or catching metal particles.

Finishes

The higher chromium and nickel content in 304 alloy allows it to take a better mirror polish compared to 430 stainless steel. This results in a more aesthetic, reflective surface finish.

430 has a grayish tone and cannot match the luster and shine achieved by 304. It also becomes more scratch resistant with polishing.

Welding

304 stainless steel is easier to weld and achieves higher quality welds compared to 430 SS. The nickel in 304 stabilizes the austenitic structure, preventing carbide precipitation and maintaining corrosion resistance in the heat affected zone near welds.

430 welds are more susceptible to oxidation and corrosion, so careful shielding gas coverage and preheating is required. Lower heat inputs should be used to avoid cracking. Welding 430 also produces magnetic welds.

Availability

As common stainless steel grades, both 430 and 304 are widely available from stock at steel suppliers and metal warehouses. Shortages of either grade are uncommon. That’s one of the reasons we like them.

Sustainability

An environmental advantage of 304 and 430 stainless steel is that they are 100% recyclable at the end of their service life. This makes them a sustainable, green material choice since they can be reused indefinitely.

What is 304 stainless steel sheet?

In sheet form, grade 304 stainless steel brings its signature properties to construction, kitchenware, appliances, transportation, and other industries. This popular austenitic grade offers unmatched corrosion resistance thanks to its 18% chromium and 8% nickel content. 304 sheet has impressive formability and durability, allowing it to be extruded, drawn, pressed, or bent into complex shapes. Its weldable and hygienic nature make it ideal for food processing and medical equipment where cleanliness is paramount. Whether it’s cladding skyscrapers, outfitting restaurant kitchens, or building chemical plant components, 304 stainless steel sheet combines versatility, workability, and endurance. That’s why it’s the first choice for fabricators across sectors.

Choosing the Best Grade for Your Use

So when should you choose 430 or 304 stainless steel?

Use 430 stainless steel for low-cost applications like automotive trim, indoor appliances, and non-critical fasteners where some corrosion is tolerable. Choose 304 stainless steel for outdoor kitchen appliances, chemical equipment, architectural panels, saltwater environments, and applications needing good machinability, weldability, and heat resistance. 

For decorative finishes like railings and trims, 304 will give a chrome-like mirror finish compared to 430. If your application requires non-magnetic properties, 304 is the better choice over magnetic 430 steel. Consider the expected environment – 304 does better in acidic, saline conditions, while 430 can work for milder exposures. 

Understanding the differences between 430 and 304 stainless steel allows you to select the optimal grade for your specific application requirements. Carefully weigh factors like corrosion resistance, strength, appearance, cost, and fabrication methods as you choose between these two versatile alloys.

Are 340 and 430 stainless steel ferritic, austenitic, or martensitic?

While 430 and 304 stainless steel might seem similar, peeking at their microstructures reveals fundamental differences. Grade 430 has a ferritic crystalline structure, meaning its atoms form a body-centered cubic lattice. This gives 430 its magnetic properties. But 304 owes its corrosion resistance to its austenitic structure – a face-centered cubic lattice providing ductility and non-magnetic behavior. The secret lies in 304’s nickel content, which stabilizes the austenite phase at room temperature. Materials engineers leverage these microscopic distinctions between ferritic 430 and austenitic 304 stainless steel to get the best performance for specific applications. When you understand the physics underlying steel grades, you gain power over material selection.

Is 430 or 304 grade stainless steel rust proof?

Corrosion prevention is a top priority in stainless steel design. While grade 430 offers decent corrosion resistance thanks to its chromium content, 304 goes the extra mile. With 8-10.5% nickel amplifying the protective power of 18% chromium, 304 stainless stands up to oxidizing acids, alkaline solutions, seawater, and organic chemicals. Its high nickel imparts passivity, drastically lowering its corrosion rate. Cold working 304 increases its corrosion resistance even further. When your project calls for maximum rust prevention, choose 304 stainless over its more susceptible 400-series counterparts.

Is 304 or 430 grade stainless steel magnetic?

Magnetism seems like a strange trait to consider when selecting structural metals. But magnetic properties can actually be critical in certain applications. Grade 430 stainless steel is ferromagnetic, meaning magnets stick and it can be permanently magnetized, which is useful for holding doors open or separating metals. But 304’s austenitic structure denies magnetism, making it essential for MRI machines, scientific tools, and food processing where electrical currents affect flavor. The microscopic arrangement of atoms determines if stainless steel grades like 304 and 430 attract or repel magnets. So consider the magnetic qualities you need when choosing those all-important alloys.

What is the hardness of 430 and 304 stainless steel?

When engineers need to know a stainless steel’s resistance to indentation, they pull out the Brinell Hardness scale. By pressing a carbide ball into the steel’s surface under 3000 kg of force, they can measure the diameter of the impression left behind. The larger the impression, the lower the Brinell Hardness Number (BHN). Tests reveal that grade 430 stainless steel has a BHN of 183. But 304 achieves a BHN of 201 due to its higher nickel content. The takeaway is that 304 withstands dents, scrapes, and surface damage more effectively. Whenever your application calls for steel that can take a beating, choose the variety with superior hardness.

Is grade 304 or grade 430 stainless steel better?

At first glance, higher-performing 304 stainless steel seems like the obvious choice over 430. With its nickel addition bolstering corrosion resistance, hardness, weldability, and formability, 304 offers greater longevity and versatility in the harshest conditions.

But 430’s lower alloy content also makes it less expensive. And in applications where moderate corrosion protection is acceptable (like mounting a range hood indoors), 430 is the better option.

You can put 304 in your home, but it’s typically overkill. But if you like the finish better or have other reasons, go for it.

For critically important outdoor structures, marine environments, and highly fabricated components where quality trumps price, 304 is the wiser investment. Consider both alloys’ strengths and weaknesses, evaluate cost trade-offs, and make an informed decision on what steel variety best fits your specific needs.

What does all this mean for you and your range hood purchase?

At Proline, we provide residential kitchens with durable, high-performing, commercial-grade range hoods. Corrosion resistance and longevity are among our top priorities. We build hoods to withstand hot, greasy cooking conditions day after day.

Though initially more expensive, 304 stainless steel’s superior corrosion resistance compared to 430 makes it the ideal choice for your next outdoor range hood. With its higher nickel content enhancing passivity, 304 stainless can handle exposure to heat, oil, steam, and cleaning chemicals while maintaining its shine.

Our highest quality 430 stainless steel gets the job done inside your home as well. We choose the best quality stainless steel for our kitchen appliances so that your kitchen stays safe and looks beautiful for years to come.

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