409 vs 439 Stainless Steel – What’s the Difference

409 vs 439 Stainless Steel

Stainless steel is a popular material used in manufacturing various products, including automotive parts, kitchen appliances, and industrial equipment. There are many different types of stainless steel, each with unique characteristics and advantages. Two popular types are 409 and 439 stainless steel. These alloys are used in applications where corrosion resistance is necessary, but what makes them different? This post explores the differences between 409 and 439 stainless steel and their respective uses.

What is 409 Stainless Steel?

409 Stainless Steel is a type of ferritic steel that is commonly used in automotive applications, kitchen equipment, and exhaust systems. The composition of 409 stainless steel makes it highly resistant to corrosion and oxidation, allowing it to stand up to harsh environments without deteriorating. This steel is great because it is low-cost, easy to work with, and possesses excellent weldability properties.

What is 439 Stainless Steel?

Have you ever heard of 439 stainless steel? It may not be the most popular material but it has its uses. This type of stainless steel is known for its ability to resist corrosion and high temperatures, making it a popular choice for exhaust systems in cars and trucks. Additionally, it’s a cost-effective option compared to other types of stainless steel.

Difference Between 409 and 439 Stainless Steel

409 stainless steel is the cheapest form of stainless steel available. It offers greater resistance to corrosion than carbon steel but at a lower cost and with lesser durability. 439 stainless steel provides superior corrosion resistance over 409 grade due to its better chromium content; however, it is more expensive and requires higher fabrication strength.


The major difference between 409 and 439 stainless steel is their chemical composition. 409 stainless steel contains 11% chromium, while 439 stainless steel contains 18%. This difference in chromium content gives 439 stainless steel better corrosion resistance than 409 stainless steel. Additionally, 439 stainless steel contains titanium, further improving its corrosion resistance and making it more durable in high-temperature environments.


Another difference between 409 and 439 stainless steel is their formability. 409 stainless steel has lower formability than 439 stainless steel due to its higher carbon content and lower levels of molybdenum. This means 409 stainless steel is less easily formed into complex shapes than 439 stainless steel.


409 stainless steel has higher weldability than 439 stainless steel due to its lower carbon content and higher levels of molybdenum. It can be welded with various welding techniques, including gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW). On the other hand, 439 stainless steel has lower weldability due to its higher carbon content and lower levels of molybdenum, which means that it should only be welded with GTAW or laser welding techniques.


The cost of 409 and 439 stainless steels vary depending on the grade and supplier. Still, 409 stainless steels are generally less expensive than 439 steels due to their simpler chemical composition and lower production costs. However, when considering the cost of materials for a project, it’s important to consider the initial and long-term costs associated with maintenance and replacement costs due to corrosion or other damage caused by using the wrong material for the application.


Due to their differences in composition, 409 and 439 stainless steels have different applications where they are most suitable for use. 409 Stainless Steel is typically used for automotive exhaust systems because of its low cost and good weldability, while 439 Stainless Steel is often used for applications requiring superior corrosion resistance, such as kitchen appliances or outdoor furniture, due to its improved corrosion resistance compared to 409 Stainless Steel


In summary, 409 and 439 stainless steel are ferritic alloys but differ in cost and corrosion resistance. The alloys in 439 stainless steel make it more corrosion-resistant, ideal for high-heat environments like exhaust systems. Meanwhile, 409 stainless steel is more affordable and suitable for applications where corrosion resistance is essential but doesn’t need to withstand high temperatures. Understanding the differences between these two alloys allows manufacturers to choose the most suitable one for their specific application, which will ultimately save them money and help extend the lifespan of their products.



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