Whether you work in the marine or automotive industry, you need reliable materials that can withstand corrosion, pressure, and harsh conditions. Stainless steel grades 304 and 304L are a great help in this regard. They are widely used austenitic stainless steels known for their excellent durability and versatility. But what exactly is the difference between the two? In this article, we are going to guide you on 304 vs 304L stainless steel, their key differences, and potential applications. Continue reading!
What Is 304 Stainless Steel?
The 304 is actually a common stainless steel grade that’s used in most industrial and architectural applications. It’s also known as 18/8 or 18/10 primarily because it contains 18% chromium and 8% to 10% nickel.
Common features include high tensile strength, great ductility, and resistance to temperatures. That’s why its demand is continuously increasing, and the North American 304 stainless steel market is expected to hit a massive $20 billion by 2032.
What Is 304L Stainless Steel?
In 304 vs 304L stainless steel, the latter is an extra-low-carbon austenitic steel alloy with a maximum carbon content of 0.03%. The low carbon content reduces carbide precipitation during the welding and forming of 304L steel. Hence, you can use it for a variety of applications requiring high corrosion resistance, such as chemical processing equipment and pressure vessels.
304 vs 304L Stainless Steel: Main Differences
In 304 vs 304L stainless steel, the primary differences lie in the carbon content, weldability, heat resistance, and cost. Let’s discuss these in detail:
Carbon Content
The primary difference between 304 and 304L is in their carbon content. 304 stainless steel has a maximum carbon content of 0.08%, while 304L has a maximum carbon content of 0.03%. This significantly impacts the weldability, strength, and corrosion resistance of both grades.
Weldability
304 has good weldability, but it requires annealing afterwards to prevent corrosion. It’s a controlled process of reheating a welded component to a specific temperature below its critical transformation range, holding it there, and then cooling it slowly. The goal is to reduce residual stress and the risk of cracking. On the other hand, 304L has way superior weldability and doesn’t even require post-weld annealing.
Corrosion Resistance After Welding
In 304 vs 304L, the latter offers better corrosion resistance after welding; all hail its low carbon content. There’s no chromium carbide precipitation, making this stainless steel grade suitable for harsh conditions. However, 304 is also moderately corrosion-resistant, but it is prone to intergranular corrosion at welds.
Mechanical Properties
Grade 304 has a higher yield strength, typically over 205 MPa, compared to 304L, which is 170 to 200 MPa. It also shows higher tensile strength than 304L, but the latter has incredible weldability that makes it stand out.
Heat Resistance
Both 304 and 304L stainless steel have excellent oxidation resistance at high temperatures, but 304L is a slightly superior choice for high-temperature environments. The 304L avoids sensitization, making it ideal for applications that require heating, such as welding, exhaust systems, or heat exchangers.
Cost and Availability
304 is generally inexpensive and suitable for standard projects and non-welded applications. On the other hand, 304L is a bit more expensive because it requires precise manufacturing to achieve its low carbon content.
304 vs 304L Stainless Steel Comparison Table
For better understanding, here’s a comparison table that shows the major differences in 304 vs 304L stainless steel:
Feature | 304 Stainless Steel | 304L Stainless Steel |
Carbon Content | Up to 0.08% carbon | Up to 0.03% carbon |
Weldability | Good, but required post-weld annealing | Superior, resists carbide precipitation, and ideal for harsh environments |
Mechanical Properties | Higher yield and tensile strength, as well as hardness | Quite low yield and tensile strength |
Heat Resistance | Good oxidative resistance | Slightly better than 304 since it avoids sensitization |
Cost | More affordable and widely available | Expensive |
Why Does Lower Carbon Matter?
Low carbon content in stainless steel is important for enhancing the corrosion resistance, particularly after welding. For instance, when you opt for a high-carbon grade, it results in the formation of chromium carbide in the heat-affected zone.
There’s little to no chromium available to form the chromium oxide layer that protects against rust and corrosion. Nonetheless, low-carbon steel eliminates the risk of this sensitization, boosting corrosion resistance and lowering hardness, making the material easy to form and bend.
When to Use 304 Stainless Steel?
304 stainless steel is inexpensive, with good ductility and corrosion resistance. You can use it for general-purpose applications, especially in food processing and indoor architectural features.
When to Use 304L Stainless Steel?
In 304 vs 304L stainless steel, you should use the latter for heavy-gauge components that require welding and still maintain high corrosion resistance. From industrial equipment to marine and coastal vessels, this material is ideal for all. But note that it’s slightly more expensive, so consider your budget and decide accordingly.
Common Applications of 304 and 304L
Here’s an overview of the potential applications of 304 and 304L stainless steel:
304
- Due to its porous and easy-to-clean nature, 304 stainless steel is used in kitchen counters, brewery equipment, and food-processing machinery.
- Structural components such as handrails, facades, and various interior design elements.
- Manufacturing refrigerators, dishwashers, washing machines, sinks, cutlery, and utensils.
304L
- Pipework, tanks, and pressure vessels.
- Chemical handling equipment, such as heat exchangers, that resists corrosive materials.
- Architectural elements like exterior panels, decorative trim, and fencing.
- Automotive and aerospace exhaust systems.
How to Choose Between 304 and 304L
If you are still confused about which one to choose between 304 and 304L stainless steel, here are some tips that can help you:
- Consider the welding requirements: if your project needs extensive welding, go with 304L rather than 304 stainless steel.
- For moderate environments, 304 is a better choice, but in moist or high-chemical-exposure sites, you should opt for 304L.
- If cost is a major concern and your application is standard (non-welded), 304 stainless steel can be a better choice.
Frequently Asked Questions
Is 304L better than 304?
No, 304L isn’t better than 304, but for some specific applications, it’s a superior choice.
Can 304 and 304L be used interchangeably?
No, 304 and 304L cannot be used interchangeably, as they have different chemical compositions and properties.
Is 304L easier to weld?
Yes, 304L stainless steel is easier to weld and solves the major concern of intergranular corrosion.
Does 304L have lower strength?
Yes, 304L has lower strength than 304 stainless steel because it has lower carbon, which is also the strengthening agent.
Talk to Jianglin Steel About 304 and 304L Supply
So, in 304 vs 304L stainless steel, whichever you choose, ensure it’s reliable and certified. Wondering where you can get it? Jianglin Stainless Steel is the ideal one-stop shop. Place your custom order today and let us handle the rest for you!
