400 Series Stainless Steel

Corrosion-resistant steel at an affordable price

400 series stainless steels are durable, high-performance metals that are well suited for a wide variety of applications. Their lack of nickel makes them somewhat less corrosion-resistant than 300 series metals, but it also puts them at a more attractive price point. The iron composition of 400 series stainless steel also gives it magnetic properties.

At Cumberland Diversified Metals, the 400 series metals that we typically deal in are 409 and 430 stainless steel. We also have access to 410, 439 and 441 stainless steel. These metals are straight chromium alloys that have low carbon and are magnetic but not heat treatable. Some of these grades can be processed to a polished finish.

Properties

400 series ferritic stainless steels are made primarily of iron, which gives them magnetic properties, and chromium, which gives them stainless and corrosion-resistant properties. The absence of nickel in their composition makes them more cost-effective than 300 series stainless steels. They are known for being easily welded or fabricated. 400 series stainless steels can be further differentiated by their crystal structure at the atomic level.

We commonly deal in 400 stainless steels that are either ferritic — with a body-centered cubic (BCC) crystal structure across all temperatures — or martensitic — with a body-centered tetragonal (BCT) structure formed by heating and quenching austenite.  Ferritic stainless steels usually have more ductility, lower tensile strength, and stronger resistance to corrosion than martensitic stainless steels. Martensitic stainless steels are generally harder and stronger, with a high degree of wear resistance.

Grades and applications

Different levels of carbon and chromium create differences between grades of 400 series stainless steel, producing various characteristics and changing their degree of hardness, strength, and resistance to corrosion.

Ferritic:

409 stainless steel applications

• Exhaust systems
• Mufflers
• Catalytic converters
• Home heating systems
• Farm equipment

410S stainless steel applications

• Automotive exhaust components
• High temperature applications

430 stainless steel applications

• Commercial kitchens
• Countertops
• Range hoods
• Flatware
• Roofing
• Siding

439 stainless steel applications

• Exhaust systems
• Furnace exchangers
• Hot water tanks

441 stainless steel applications

• Automotive manifolds
• Exhaust system components
• Coal mining equipment
• Components in contact with corrosive or oxidizing agents

Martensitic:

410 stainless steel applications

• Cutlery
• Surgical instruments
• Springs
• Shears

Shapes and forms

We buy and sell the 400 series stainless steel sheet, plate, and coil you’re looking for. Contact us today to find out what we currently have in our expansive inventory.

Frequently Asked Questions (FAQs) about 400 series stainless steel

What is 400 series stainless steel’s composition?

400 series stainless steel primarily consists of iron and chromium. The specific proportions will depend on which grade you select, but the general composition is as follows: Iron is the primary element, comprising more than 50% of the metal’s makeup. Chromium is the next largest element, ranging from 10.5% to more than 18%, and imbuing the steel with its stainless property and corrosion resistance. Most 400 series stainless steels have less than 0.1% carbon, and the remaining elements may include small quantities of silicon, manganese, molybdenum, nickel, and/or aluminum.

Is 400 series stainless steel magnetic?

Yes, 400 series stainless steel is magnetic due to its body-centered cubic (BCC) crystal structure and large portion of ferrous iron.

How would you compare 300 vs. 400 series stainless steel?

Unlike the non-magnetic austenitic 300 series stainless steel, 400 series stainless steel’s iron composition enhances its magnetic nature. 300 series stainless steel contains higher levels of chromium and nickel than steel in the 400 series making 300 series metals tougher and more corrosion resistant. The lack of nickel also makes 400 stainless steel a more cost-effective metal.

How is 400 series stainless steel’s corrosion resistance?

400 series stainless steel has good corrosion resistance, although it is not as high as 300 series stainless steel. The precise measure of corrosion resistance depends on how much chromium the selected grade of stainless steel contains.

What is the difference between ferritic and martensitic stainless steel?

The crystalline structures of these two steels give them different characteristics. Ferritic steel has a body-centered cubic (BCC) crystal structure across all temperatures, whereas martensitic steels have a body-centered tetragonal (BCT) structure formed by heating and quenching austenite. Ferritic stainless steels tend to have higher ductility, lower tensile strength, and stronger corrosion resistance than martensitic stainless steels.