Stainless steel is found in a vast range of applications from household appliances to medical instrumentation to industrial equipment and more. There are multiple grades of stainless steel, and they may be magnetic or non-magnetic, depending on their composition. Magnetic stainless steels must contain iron and have a martensitic or ferritic crystal structure.
304 stainless steel is one of the most common grades and is widely used. It has an austenitic structure and as such is not magnetic; however, there are ways to make this material magnetic. Keep reading to learn more about stainless steel and its magnetic properties so you can select the appropriate type for your project.
What is Stainless Steel?
Stainless steel is known for its excellent corrosion resistance, minimal tarnishing, biocompatibility, and wide utility in diverse applications.
Stainless steel is a metal alloy composed of multiple metals, primarily chromium and iron. The different grades of this alloy contain varying proportions of iron, chromium, silicon, carbon, nitrogen, and manganese. Stainless steel materials must contain at least 10.5% chromium and no more than 1.2% carbon. Each grade of stainless steel has a slightly different composition and different properties.
The five different categories of stainless steel are based on their crystalline structure:
- Austenitic stainless steels.
- Ferritic stainless steels.
- Martensitic stainless steels.
- Duplex stainless steels.
- Precipitation-hardened steels.
What Makes Stainless Steel Magnetic?
Some types of stainless steel are magnetic, or can become magnetic. Here’s what you need to know:
- Magnetism depends on both the presence of iron and crystalline structure of the stainless steel.
- Ferritic (i.e., 430 and 409) and martensitic (i.e., 410 and 420) stainless steels are magnetic because they have Body-Centered Cubic (BCC) crystalline structures. Electrons can easily align in this configuration and create a magnetic field.
- Austenitic stainless steels 304 and 316 are not magnetic because they have Face-Centered Cubic (FCC) structures, which keep electrons from aligning and prevent the formation of a magnetic field.
Is 304 Stainless Steel Magnetic?
In general, austenitic, or 304, stainless steel is not magnetic due to its crystal structure; however, its nickel content also plays a role. A high nickel content stabilizes the crystal structure of austenitic steel, which can keep it from changing into a martensitic structure as a result of heat treatment or cold working processing. 304 Stainless steel consists of 18-20% of chromium, 8-10.5% of nickel, and smaller amounts of other elements.
It’s important to remember that it is the structural change, rather than a composition change, that can cause 304 stainless steel to exhibit some degree of magnetism after processing.
Why are Stainless Steel Certification and Standards Important?
There are multiple certifications and standards to be aware of when choosing a manufacturer for stainless steel products. Companies that comply with these, such as Marlin Steel, provide high-quality products with reliable performance. Look for these indicators of quality:
- ASTM Standards. The American Society for Testing and Materials establishes specific standards for stainless steel materials. ASTM A240 provides guidelines on the chemical composition, mechanical properties, and testing procedures for stainless steel sheets and plates.
- ISO Certifications. The International Standards Organization, or ISO, develops standards pertaining to quality, safety, and efficiency. In manufacturing, ISO 9001:2015 certification is a sign that a manufacturer is committed to quality in all aspects of its operations.
- Medical Device ISO 13485:2016 Certification. This standard outlines the requirements for a quality management system specific to medical devices. Certification indicates that a manufacturer meets strict regulatory and customer requirements for the design, production, and servicing of medical-grade products.
Why Choose Marlin Steel for Your Stainless Steel Needs?
Since 1968, Marlin Steel has been a leading manufacturer of custom stainless steel wire baskets, brackets, hooks, racks, carts, and other wire forms. We serve many industries, including aerospace, defense, medical, food processing, and automotive.
Our Baltimore, MD facility is equipped with advanced CNC wire forming equipment for precision manufacturing to meet your project requirements. Contact us to learn more about our capabilities or request a quote for your next project today.
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