Does SS304 stick to magnets?

Does SS 304 Stick to Magnets?

SS 304 is generally non-magneticin its annealed (heat-treated) condition, meaning it does not stick to magnets under normal circumstances. This is due to its austenitic microstructure, which is characteristic of 300-series stainless steels like SS 304 (SA 240 GR 304) and SA 240 GR 316. The SA 240 304 non magnetic properties make it ideal for applications requiring non-magnetic behavior, such as electronic equipment, medical devices, and food processing.

However, SS 304 can exhibit slight magnetism under specific conditions:

• Cold Working: Processes like rolling, bending, or forming (e.g., for plat SS 304 3mm or plate 2 mm SUS 304) can induce martensitic transformation, creating small magnetic regions. The degree of magnetism depends on the extent of cold work—light deformation causes minimal magnetism, while heavy deformation (e.g., in drawn wire) increases it.
• Welding: Welded areas, such as in SA 240 GR 304 pipe, may develop slight magnetism due to microstructural changes or ferrite formation in the weld zone.
• Contamination: Iron particles or carbon steel residue on the surface (e.g., from tools) can cause SS 304 to appear magnetic, though this is superficial.

In practical terms, annealed SS 304 plates or sheets (e.g., plat stainless 304) will not stick to a magnet, but heavily cold-worked or welded SS 304 may show weak attraction. This distinguishes SS 304 from ferritic (e.g., SA 240 GR 430) or martensitic (e.g., SA 240 GR 410) grades, which are inherently magnetic.

Why is SS 304 Non-Magnetic?

The non-magnetic nature of SS 304 is due to its austenitic crystal structure, stabilized by:

• Nickel (8-10.5%): Promotes austenite, a non-magnetic phase.
• Chromium (18-20%): Enhances corrosion resistance without affecting magnetism.
• Low Carbon (≤0.08%): Maintains austenitic stability.

Cold working can partially transform austenite to martensite (a magnetic phase), causing slight magnetism. For comparison, SS 304L (≤0.03% carbon) behaves similarly, while SA 240 GR 316L is also non-magnetic. See sa 240 gr 304l and sa 240 gr 316l.

Chemical Composition Supporting Non-Magnetic Properties

For detailed specs, refer to our SS 304 data sheet.

Testing SS 304 for Magnetism

To confirm SS 304’s non-magnetic properties:

• Magnet Test: Place a magnet on an annealed SS 304 surface (e.g., plat stainless 304). No attraction confirms non-magnetic behavior. Weak attraction suggests cold-working or contamination.
• Chemical Analysis: Use XRF to verify composition, distinguishing SS 304 from magnetic grades like SS204 vs SS 304 or SA 240 GR 430.
• Supplier Certification: Check the mill test certificate (MTC) for SA 240 GR 304 to ensure annealed condition.

For high-temperature applications where magnetism is a concern, explore sa 240 gr 304h.

Applications Leveraging Non-Magnetic Properties

SS 304’s SA 240 304 non magnetic properties are critical for:

• Food Processing: Tanks and equipment (hygienic, non-magnetic).
• Medical Devices: MRI-compatible instruments and implants.
• Electronics: Non-magnetic components to avoid interference.
• Chemical Industry: Vessels and SA 240 GR 304 pipe for mild corrosives.

For chloride-heavy environments, consider sa 240 gr 317l.

Pricing and Availability

As of October 14, 2025, SS 304 plate prices (2B finish, 3-6mm) range from $1.55-$3.50/kg globally. Gangsteel offers $1.60/kg FOB (MOQ 1 ton) for sa 240 gr 304 plates, including sizes like plate 2 mm SUS 304.

Why Choose Gangsteel?

Gangsteel provides certified SS 304 plates with consistent SA 240 304 non magnetic properties and competitive SS 304 plate price. Our inventory includes SA 240 TP 304/304L dual-certified plates. For quotes or to learn what is SA 304, visit our astm a 240 stainless plate page or email admin@gangsteel.com.