Are you unsure whether to go with 304 stainless steel or grade 316? If you don’t know the difference between the two, you’re in the right place. We’ll delve deeper and explain the properties of both combined metals so you’ll have a better understanding before choosing which one to use for your application.
What Is Stainless Steel
Stainless steel, an iron-based alloy that contains chromium and other elements, is one of the most popular and diverse metal materials available to designers. With over 150 types of stainless steel, including 302 stainless, many with different properties, it’s easy to see why stainless steel is more popular than others like aluminum.
Stainless steel is used in a wide range of applications due to its strength, formability, mechanical properties, ability to resist oxidation and corrosion, and ease of fabrication.
Available in everything from low carbon steel to high strength alloys, the sheer variety of stainless steel grades means a wide range of materials – used for everything from cookware and medical equipment to oil rigs and other marine applications.
How To Choose Grades
When choosing a grade of stainless steel, the first step is to look at everything available and decide which characteristics are most important for the application. This will help narrow down the options and make the selection process easier.
Another factor to consider is the application. For example, if the application will be exposed to high temperatures, then a grade with high carbon content, high melting point, and excellent strength-to-weight ratio is typically desired. If the application must be resistant to chemical exposure, then a grade of stainless steel that contains significantly more chromium and nickel will be the best choice.
It’s also important to consider the desired end use of the material. However, the final choice is often based on cost.
Stainless steel grades are not all created equal, and some will be more expensive than others because they are costlier to produce.
316 vs 304 Stainless Steel
So what’s the difference between Grade 304 and Grade 316 stainless steel? Both 304 and 316 are austenitic grades of stainless steel, meaning that they are typically used in applications where formability is not a concern. The grades are almost alike in that they both contain high levels of chromium and nickel.
While both grades are very similar in terms of physical properties, their chemical properties are very different – and this is what sets them apart. They are both used for applications where resistance to corrosion and oxidation are the most important factors. The primary difference between these grades is in the chemical composition – Grade 316 has a higher molybdenum content compared to grade 304.
Grade 304 – a ferritic grade – contains chromium but not molybdenum. Grade 304 is often the more economical of the two grades, and it is a good choice for applications where formability is not a concern and for applications that will not be exposed to chemicals or high temperatures.
It still has good corrosion resistance, but not as good as 316. Still, it is a very popular grade due to its relatively low cost.
Grade 316 – a martensitic grade – contains both chromium and molybdenum. The molybdenum in 316 reduces the amount of distortion that the material experiences during heating, and this results in a material with better formability.
Molybdenum makes the material more resistant to corrosion and oxidation. With its minimum distortion upon heat treatment, it also makes it an ideal grade for applications involving high temperatures and where formability is a concern.
The increased molybdenum content of Grade 316 makes it more expensive than 304, but it also means that the material will be more durable and corrosion-resistant – making it the better choice in applications where exposure to chemicals or marine environment.
Choose the Best Option for Your Application
When deciding between grades 304 and 316 stainless steel, the first step is to determine which grade best fits the application and then choose the most economical option. Generally speaking, Grade 304 stainless is better for applications where formability is not an issue, while Grade 316 is the better choice where formability is essential. Or, you can also opt for 17-7 stainless if you need extreme hardness and strength, as well as optimal fatigue properties, aside from corrosion resistance.