304 vs. 316 Stainless Steel: Which Should I Use?

As a passionate DIYer, you know how important it is to use high-quality materials in your projects. When it comes to metal components, you can’t get much better than stainless steel. Valued for its versatility, stainless steel is a favorite among DIYers of all stripes. Two popular stainless steel grades, or types, are 304 and 316. They’re very similar, but there are some factors to consider when choosing between them. This blog compares the top features and recommended uses of 304 and 316 stainless steel.

What Is Stainless Steel Made Of?

Before we discuss features, it’s important to cover what stainless steel contains. Stainless steel is an alloy, or a mixture, of several elements. Iron is the most abundant material in all grades of stainless steel. Beyond that, different grades contain different ratios of other elements. One grade may have an element that another doesn’t.

That’s the case with 304 and 316 stainless steel. Here is a summary of the contents of each grade:

304 Stainless Steel

• Chromium: approx. 18-20%.
• Nickel: approx. 8-10.5%.
• Manganese: max 2%.
• Silicon: max 1%.
• Carbon: max 0.08%.
• Phosphorus: max 0.045%.
• Sulfur: max 0.03%.
• Other trace elements, including nitrogen and molybdenum.

316 Stainless Steel

• Chromium: approx. 16-18%.
• Nickel: approx. 10-14%.
• Molybdenum: approx. 2-3%.
• Manganese: max 2%.
• Silicon: max 1%.
• Carbon: max 0.08%.
• Phosphorus: max 0.045%.
• Sulfur: max 0.03%.
• Other trace elements, including nitrogen.

As you can see, 304 and 316 have different amounts of chromium and nickel. 316 also has a measurable amount of molybdenum, while 304 contains very little. The amount of each element in a grade of steel affects that grade’s final properties:

• Chromium improves corrosion resistance, strength, hardness and high-temperature resistance.
• Nickel increases corrosion resistance, ductility and toughness. It also boosts high-temperature strength and stability, and low-temperature toughness and impact resistance.
• Molybdenum contributes to strength and high-temperature stability. However, its main purpose is to enhance corrosion resistance.

So, it makes sense that steel grades with different contents don't have the same capabilities. Let’s discuss the top features of 304 and 316 stainless steel to help you decide which one is best for your needs.

Stainless Steel Features

Corrosion Resistance

Stainless steel has exceptional resistance to corrosion. It's perfect for exposure to environmental factors such as humidity, moisture and salt. Corrosion resistance is mainly a concern for marine and outdoor applications.

When it comes to choosing between 304 and 316 for corrosion resistance, there is one clear winner. Higher concentrations of nickel and molybdenum give 316 superior corrosion resistance over 304.

316 is ideal for applications that will be partially or constantly outdoors — especially if water is involved. 316 stands strong against corrosive agents such as moisture, humidity and salt. In the marine world, 316 is perfect for:

• Liveaboard sailors.
• Boats that get year-round use (especially in humid environments).
• Boats that are used on saltwater.
• Permanent outdoor structures such as shade sails.
• And more.

304’s corrosion resistance isn’t on par with 316’s, but it still stands strong against corrosive agents. It has a respectable amount of nickel and even more chromium than 316. So, 304 stainless steel is still a good choice for marine applications! Just know that it’s better suited for occasional-use or freshwater boats. Heavy use, extreme humidity and constant saltwater exposure cause 304 to corrode faster than 316 in the same conditions.

Not a sailor? No problem. Both metals can be used indoors and for craft applications.

Strength & Durability

The next factor to consider is strength. Both grades offer impressive strength and durability for marine and non-marine projects. However, 316 has an advantage in this category as well.

Chromium and molybdenum also give 316 extra strength compared to 304. Nickel helps too, but its effect on strength is mostly temperature-dependent. (More on that in the next section.)

316 takes on heavy-duty projects and permanent outdoor use with ease. DIYers utilizing this steel can confidently create robust, sturdy outdoor or load-bearing structures. Even under harsh conditions and marine environments, 316 hardware remains durable and functional.

But 304 is no slouch in the strength department either. Boasting good tensile strength, 304 is ideal for projects that need robust yet lightweight hardware. This includes most craft applications and general sailing needs. (But note that 304 may show weakness in high-stress situations.) Choose 304 for bag hardware, garment fasteners and other light- to medium-duty DIY needs.

Temperature Tolerance

Another thing to consider is whether you'll use stainless steel in extreme temperatures. Under normal conditions, heat and cold exposure shouldn’t be a problem. 304 and 316 both perform well in temperatures typical of most DIY and marine settings.

If you need stainless steel that can tolerate excessive heat (such as an industrial setting) or cold (such as climates near the poles) for short periods of time, 304 and 316 are both good options.

316 has a slight advantage over 304 in this area due to its molybdenum content. However, the difference is negligible. High nickel content helps both grades resist temperatures from about -50º F (-45ºC) to about 1,400ºF (925ºC) for short periods of time without weakening much.

On the flip side, long periods of time in these temperatures cause the steel to weaken and corrode easier. If you need stainless steel for a project that will be exposed to extreme temperatures consistently, 304 and 316 may not be right for you.

Cost

Finally, let’s cover cost. Choosing a stainless steel grade can have a big impact on your DIY budget. 304 and 316 offer great value for the money considering their long-lasting properties. But one may be a better fit for your budget (and your project needs) than the other.

304 is generally more budget friendly due to its lower nickel and molybdenum content. Molybdenum is a rare metal, so it makes sense that the steel with less molybdenum is less expensive. 304 is also easier to make and is more in demand due to its versatility, so it’s produced in greater volumes than 316. This grade is a great choice for DIYers seeking a cost-effective option without sacrificing quality.

On the other hand, 316 may be best for DIYers whose biggest concern is performance over cost. Molybdenum is rare and expensive, but it does greatly increase 316’s corrosion resistance. Because of this, manufacturers often position 316 as a premium or specialty grade and charge more for its added benefits. 316 is worth the investment for projects requiring weather resistance and enhanced durability.

Recommended Uses

304 is a versatile material that is used in various industries and environments. Common uses include:

• Nuts, bolts, screws and other fasteners.
• Garment and bag hardware.
• Deck hardware, railings and interior fittings for boats in freshwater or less harsh environments.
• Jewelry and clasps.
• Home décor and functional household items.
• Decorative elements.
• Projects where cost is a major deciding factor.

While 304 is a popular choice in many applications, it isn’t the best choice for some situations:

• Highly corrosive environments.
• Long-term exposure to high temperatures.
• Long-term exposure to low temperatures.
• Heavy load-bearing applications requiring extremely high strength and hardness.
• Highly abrasive environments or heavy-wear projects.
• High-sulfur environments.

Now let’s see how 316 stacks up. 316 is particularly good for aggressive/corrosive substances or environments. Common uses for this grade include:

• Marine equipment, riggings, propellers and fittings exposed to saltwater.
• Outdoor items subjected to weather exposure, such as patio furniture.
• High-temperature applications.
• High-pollution areas.
• Many load-bearing applications.
• Springs and fasteners.
• Other applications where corrosion resistance is critical.

However, 316 isn’t the most suitable option for all situations, including:

• Projects where extra corrosion resistance isn’t needed.
• Projects where cost is a major deciding factor.
• Low-oxygen environments, such as deep-sea or vacuum applications.
• High-sulfur or strongly acidic environments.
• Long-term exposure to high temperatures.
• Extremely high-stress applications.
• Long-term exposure to low temperatures.

Each stainless steel grade has its niche in marine, sewing and other DIY projects. You should carefully consider your project needs and uses before choosing a stainless steel.

Summary & Conclusion

304 and 316 stainless steel are suitable for a wide range of applications in the crafting world. When selecting the appropriate grade for your sewing projects, make sure to consider the following factors:

• Indoor vs. Outdoor Use: Will your project primarily be used indoors or outdoors?
• Corrosion Resistance: Will your project be exposed to moisture, humidity, saltwater or other corrosive agents?
• Strength & Durability: How much mechanical strength and durability does your project need?
• Temperature Tolerance: Will your project will be exposed to extreme heat or cold?
• Budget: Which grade's cost fits in your budget?

The choice between 304 and 316 stainless steel ultimately depends on your specific project needs and budget. Whether you’re shopping for boat hardware, bag hardware or something in between, 304 and 316 stainless steel are two high-quality options for your DIY needs.

We hope this blog has helped you select the best stainless steel grade for your next project. If you’re still unsure, don’t hesitate to reach out! Our customer service team is available by phone, email and the chat function on our website. We’re ready to help empower you to make an informed decision for your next DIY masterpiece.