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🧲 Can Stainless Steel Be Magnetic? The Full Story on the Magnetic Properties of Different Grades. 2024/07/26

 🔎 Why Are 304 and 316 Mostly Non-Magnetic? The Full Story on Which Stainless Steels Are Attracted to Magnets. 
Many people assume that stainless steel **is not attracted to magnets at all**, but in reality, the **magnetic properties of different types of stainless steel vary greatly!** Some are indeed non-magnetic, while others have strong magnetic properties, and some even become magnetic only after processing.
Today, we will demystify **the reason for stainless steel's magnetism** and compare which grades **are attracted to magnets**, helping you make a more informed choice when purchasing stainless steel!
📌 Why Are Some Stainless Steels Attracted to Magnets?
🔶 **The magnetism of stainless steel comes from its "metallurgical structure,"** which can be divided into the following categories:
 
✔ Austenitic Stainless Steel
✅ **Non-magnetic** (but may become weakly magnetic after cold working)
✅ Representative grades: **304, 316, 201, 202**
✅ Main applications: tableware, medical equipment, food processing equipment

✔ Ferritic Stainless Steel
✅ **Magnetic**, and will be attracted to magnets even after processing
✅ Representative grades: **430, 409, 439**
✅ Main applications: home appliances, automotive interiors, kitchenware

✔ Martensitic Stainless Steel
✅ **Strongly magnetic**, with adjustable strength and hardness through heat treatment
✅ Representative grades: **410, 420, 440**
✅ Main applications: cutting tools, turbine blades, mechanical parts
📌 Comparison of Magnetic Properties by Stainless Steel Grade
 Comparison table of stainless steel grades and their magnetism and applications, including common grades like 201, 202, 304, 316, 409, 430, 410, 420, and 440, listing their magnetic properties, characteristics, and application scope.
📌 Why Do 304 and 316 Become Magnetic After Cold Working?
Initially, **304 and 316**, as **austenitic stainless steels**, have almost no magnetism in their annealed state. However, after they undergo **cold working (such as bending, stamping, or stretching), their internal metallurgical structure may partially transform into a martensitic structure**, resulting in **weak magnetism**.
✅ **How to Demagnetize?**
To make these stainless steels **non-magnetic again**, they can be put through an **annealing process**, which allows the internal martensite to revert to an austenitic structure, reducing or eliminating their magnetism.
📌 How to Consider Magnetism When Choosing Stainless Steel?
🔶 **If a completely non-magnetic material is required** **→ Choose 304 and 316**, but avoid cold working that may cause magnetism
🔶 **If you need high strength with magnetic properties** **→ Choose 410, 420, 440**, suitable for cutting tools and mechanical parts
🔶 **If you need cost-effective corrosion resistance** **→ Choose 430, 409**, suitable for home appliances and automotive parts
🔶 **If you require high corrosion resistance but have cost considerations** **→ Choose 201, 202**, which can be used as alternatives to 304
📞 Contact Us
If you have needs for **stainless steel products**, please feel free to contact **GuoKai Steel**!
📩 LINE Official Account: @guokai
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