Do you know the right grade of stainless steel for your part?

Stainless steel is everywhere: kitchenware, cars, faucets, zippers. You encounter it so often in everyday life that it’s easy to overlook the complexity of this material.

Determining the ideal alloy for your stainless steel part is important to function, but your choice can also impact cost and lead time.

At Arbiser Machine, we’re here to help you select the perfect grade of stainless steel for your part every time.

What’s in a Grade? Comparing Common Stainless Steel Grades

There are over 150 grades of stainless steel and nearly 200 different alloy combinations. Each grade has different properties that affect factors like strength, corrosion resistance, and overall machinability. That’s a lot of options to choose from!

When it comes to machining stainless steel, we typically work with four common grades: 303, 304, 316, and 321. There are different properties and applications for each grade:

303 Stainless Steel

The addition of sulfur and selenium in its composition makes 303 stainless steel the easiest type to machine—though it has poor weldability and cannot be cold-worked. Its malleability is perfect for smaller components requiring tight tolerances, such as bearings, bushings, and fasteners.

304 Stainless Steel

Perhaps the most common type of stainless steel available today, 304 stainless steel is widely used for kitchen appliances. High levels of chromium and nickel make for a shiny and bright appearance. This grade is, however, less machineable than 303 stainless steel.

316 Stainless Steel

Also known as surgical stainless steel, 316 stainless steel is a less common and more expensive alloy. It contains a small amount of molybdenum in its blend, providing exceptional corrosion resistance even when exposed to saltwater. Because of this property, 316 stainless steel is most widely used in biomedical implants and medical equipment.

321 Stainless Steel

Designed for high heat and highly corrosive environments, 321 stainless steel can withstand temperatures up to 1,000 degrees fahrenheit. This type of stainless steel is widely used around furnaces and in aerospace and automotive applications. Its resistance to pitting and crevice corrosion, as well as its ability to grow thermally, make it the ideal material for fatigue applications such as locomotive engines. It’s not recommended for marine environments.

Choosing the Right Stainless Steel Grade for Your Part

There are a few key factors to consider when selecting a stainless steel grade for your part:

Functionality. The ideal grade of steel varies depending on the function of your part and the environment it will be used in. If you’re manufacturing kitchenware that will be placed in an acidic environment, for example, we probably won’t be able to use 304 like we would for other applications in the food service industry. We’ll recommend a stainless steel grade like 316 with corrosion resistant properties instead.

Machinability. Machinability affects cost and lead time, so we never want to choose a stainless steel grade that’s more difficult to machine when an easier grade would work just as well. Is the part going to be inside a conveyor shaft that no one will ever see? Then you probably don’t need the shiny appearance of 304. We’ll advise using 303 instead since it’s easier to machine.

Proprietary Alloys. There may be times when you need a certain size or quantity of stainless steel that can only be sourced from specific vendors with their own proprietary alloys. The material they carry may go by a different name that doesn’t correspond to the typical 300 series stainless steel grades. We’ll leverage our excellent relationships with vendors to get you the material you need, whether it’s a 300 series stainless steel or a proprietary alloy with identical properties.

The team at Arbiser Machine has the knowledge and expertise to guide you in the right direction for material selection and make you a stainless steel part that meets all specifications. Request a quote from our machine shop in Georgia and let’s get started.