Which metals actually stick to a magnet? The direct answer is iron, nickel, cobalt, and their alloys, especially carbon steel. Aluminum, copper, brass, and bronze do not. Stainless steel sits in a confusing middle ground: families like 430 are magnetic, while 304 usually is not until cold-worked. This article lists the magnetic metals, explains the physics, and gives you a five-second test to sort them. You'll also learn why stainless steel is the exception that ruins a simple rule.
The Short List: Metals That Stick
Beyond the pure elements, the metals that stick include carbon steels like 1018 or 4140, alloy steels, tool steels, and most grades of cast iron. Pure nickel and cobalt are less common in stock form, but their alloys—such as nickel-iron alloys used in magnetic shielding—are strongly attracted. What about the everyday shop favorites? 6061 aluminum, C36000 brass, C93200 bronze, and C11000 copper all slide away from a magnet. The distinction is not about color or weight; it comes down to the crystal structure of the metal. Ferromagnetic materials have magnetic domains that align in an external field, while copper's electron configuration simply does not support that alignment. So if you sweep a magnet across a mixed bin, steel and cast iron leap to the magnet; aluminum and copper stay behind.
When we say a metal 'sticks' to a magnet, we mean it experiences a net attractive force strong enough to overcome gravity and hold against the magnet. This behavior—technically called ferromagnetism—happens in materials with unpaired electrons and a crystalline lattice that allows those electron spins to align. Only three pure elements show ferromagnetism at room temperature: iron, nickel, and cobalt. Their alloys inherit the property when the alloying preserves the right crystal structure. The practical takeaway: a magnet test sorts ferromagnetic from non-ferromagnetic stock but can't identify the alloy grade—use a spark test, spectrometer, or datasheet for that. And because a magnet only senses net magnetic moment, you may also need to know whether the alloy has been cold-worked or heat-treated, since those processes can alter the microstructure and shift the result.
The Physics of Attraction
To understand why iron sticks to a magnet, look at the electron scale. In iron atoms, several unpaired electrons form magnetic domains—crystals where the spins align. In an unmagnetized piece, those domains point in random directions and cancel out. Bring a magnet close, and the domains rotate to line up with the external field, producing an attraction you feel as a pull. In a material like copper, all electron spins are paired, so there are no permanent magnetic domains to align; the metal simply doesn't respond. The same is true for aluminum, which has no unpaired d-electrons. This is why a magnet lifts steel but slides off aluminum; a weak pull on machined aluminum usually means embedded steel chips. The clean attraction you need for a reliable test only appears with ferromagnetic materials.
Contrast that with aluminum, which has no unpaired electrons in its conduction band, and you see why it never gets pulled toward a magnet. The same reasoning applies to copper, brass, and bronze—they are all non-ferromagnetic because their electron structures produce no net magnetic moment. Even though these metals are excellent conductors of electricity, their magnetic permeability is close to that of free space. That property makes them invaluable in applications where stray magnetism would interfere with sensors, medical devices, or high-frequency electronics. The absence of magnetic attraction is not a defect; it is a design feature that engineers exploit whenever they need non-interfering enclosures or mounting brackets. For instance, a copper ground bus bar can run alongside a magnetometer without skewing its readings, while a steel bracket of the same size would throw the measurement off.
Common Metals: Magnetic vs. Non-Magnetic
Within the magnetic camp, you will find the workhorse structural metals. Low-carbon steel like A36, medium-carbon alloys like 4140, and high-carbon tool steels all stick firmly. Cast iron—whether gray, ductile, or white—also responds to a magnet. On the alloy side, many nickel-iron alloys such as Mu-metal are deliberately engineered for maximum magnetic permeability, making them the go-to choice for shielding. Cobalt-based superalloys retain magnetism at high temperatures. Even a thin zinc-plated steel bracket will hold a magnet, because the plating is only a protective coating and does not change the ferromagnetic core. The only apparent exception is a magnet's ability to attract a small chip of steel that has been embedded in a non-magnetic part; that chip gives you a false-positive signal, so always inspect the surface for contamination.
Aluminum and its alloys—1050, 1060, 1350, 1070, 3003, 5052, and 6061—sit firmly in the non-magnetic column. These alloys are widely used for sheet and plate that ranges from 0.2mm to 6.0mm thick, primarily because they are lightweight, corrosion-resistant, and completely non-magnetic. The same is true for the copper family: pure copper (C11000) leads the group with 101% IACS electrical conductivity, while brass (C36000) offers free-machining behavior and bronze (C93200) delivers wear resistance for bearings. Speedy Metals' product guides and industrial libraries consistently list these alloys for electrical and marine work precisely because they won't disturb sensitive magnetic fields. In a sensor housing, a 6061 aluminum plate is the default choice because its permeability is indistinguishable from air. Over in the marine world, C93200 bronze propeller bushings operate reliably without ever being influenced by nearby magnetic fields. The practical rule: if a magnet doesn't stick, the material won't compromise your magnetic service.
The Stainless Steel Exception
The stainless steel exception trips up more than a few buyers. A 12-inch All-Clad skillet with an 18/10 stainless steel cooking surface (that's 18% chromium and 10% nickel) will not stick to a fridge magnet—the nickel stabilizes the austenite phase, which is non-magnetic. But 430 stainless, a common ferritic grade used in cheaper cookware and automotive trim, contains almost no nickel and is magnetic. In fact, the 3-ply construction of that All-Clad pan—18/10 exterior, pure aluminum core, 18/10 interior—tells you the designers chose austenitic stainless to keep the cooking surface non-reactive; the magnetic behavior is a byproduct of the crystal structure, not a selling point. So when you hear 'stainless steel doesn't stick,' remember it only applies to the austenitic family.
Practical implication: if you rely on a magnet to identify stainless steel, you can separate the ferritic and martensitic families (which stick) from the austenitic family (which usually doesn't). But be careful—cold working or severe forming can transform some austenitic stainless into a partially martensitic structure, making a 304 sheet that used to be non-magnetic develop a weak pull. This is why a magnet test is a coarse sieve, not a definitive grade ID. The skillet review's 5/5 performance score for heating and build quality doesn't change the fact that the pan's stainless is non-magnetic—but if you were welding that same grade into a sensor housing, the cold work at the bend lines could create small magnetic zones that you'd have to demagnetize. A good rule: test three spots, especially near bends and welds, before trusting a 'non-magnetic' label.
The Five-Second Magnet Test
Running a five-second magnet test is straightforward. Take a small neodymium magnet—one strong enough to lift a few pounds—and touch it to a clean, dry surface of the metal. If it snaps on and holds with firm resistance, the metal is ferromagnetic: assume steel, iron, cobalt, or a ferritic/martensitic stainless grade. If it falls away or only levitates with a slight push-pull feel, it's non-magnetic or very weakly magnetic: that points toward aluminum, copper, brass, bronze, or austenitic stainless. For a fair reading, clean off oil and paint, because a thick coating can mask the attraction. Testing at the end of a bar stock is also wise, since surfaces with heavy scale or rust can affect the pull. And always test a piece that is representative of the whole batch—a single sample with a different alloy can mislead you.
Limitations of the test are just as important to know. A magnet cannot distinguish 6061-T6 from 5052-H32 aluminum, because both sit in the non-magnetic family. It also won't tell you whether a piece of brass is C36000 or C93200—both are copper alloys and both ignore a magnet. Even within stainless steel, a cold-worked 304 can show a weak attraction; the magnet will barely hold, and an inexperienced hand might call it non-magnetic when it is actually lightly magnetic. The real lesson: use the magnet as a first-pass separator, then confirm the grade via alloy markings, certificates, or a PMI gun for critical parts. In a high-volume shop, combine the magnet test with a hardness file test—steel will file softer, while hardened tool steel will skate—to separate look-alike alloys without sending samples to a lab.
How Magnetic Knowledge Evolved
The story of magnetic metals begins with magnetite, a naturally occurring iron oxide that the ancient Greeks called 'the stone that attracts iron.' By the first century BCE, the Chinese had fashioned lodestone into directional compasses, noticing that a suspended splinter would rotate to align with Earth's magnetic field. These early observations established that only iron and iron-rich rocks responded, while copper, gold, and lead never did. The missing piece—why some metals respond and others do not—waited until the 20th century when quantum mechanics explained electron spin alignment and magnetic domain behavior. As a result, a 2,000-year-old practical test became a predictive material property. The timeline from lodestone to modern alloy design shows how a simple shop-floor trick evolved into a precise metallurgical tool. That evolution is still happening today, as we will see in the modern timeline.
In the modern era, the industrial side of magnetic knowledge has driven aluminum's rise as a non-magnetic structural metal. Alcoa, for example, built the world's largest light metals research facility on a 40-acre campus near Pittsburgh, and in 2014 announced a 10-year, $1.1 billion contract with Pratt & Whitney to supply advanced aluminum alloy fan blades for jet engines—a component where magnetism would be entirely unacceptable in the hot-section instrumentation. Two weeks earlier, the company had spent $2.85 billion to acquire Firth Rixson, a maker of jet-engine components, to strengthen its aerospace portfolio. These investments reflect a shift from steel to aluminum, driven by aluminum's non-magnetic character, weight savings, and corrosion resistance. The development of new aluminum alloys over the past two decades has expanded the range of non-magnetic options available to engineers, from 2xxx series to 7xxx series.
Choosing for Magnetic or Non-Magnetic Service
Choosing between magnetic and non-magnetic service comes down to the operating environment. If you are building a sensor enclosure that must not distort a magnetic field, reach for aluminum (6061 or 5052), copper, or a genuinely non-magnetic austenitic stainless like 316. If you need a magnetic mounting stub or a part that will hold a magnet in place, carbon steel, nickel-iron, or a ferritic stainless is the obvious pick. The decision also hinges on processing: cold forming, welding, and even grinding can induce residual magnetism in otherwise non-magnetic austenitic grades, so specify a demagnetization step after heavy fabrication. And do not forget corrosion—the non-magnetic copper alloys like C36000 brass and C93200 bronze bring their own corrosion and wear profiles that you must match to the service. A quick way to document your choice is to note the expected magnetic permeability on the drawing; for non-magnetic service, specify a relative permeability of 1.01 or lower.
When you have narrowed down the material class, Speedy Metals is one supply channel that publishes relevant product guides alongside its stock. Their site lists current lead times (2-3 days, 4-5 for prepared burn plate) and a 10% newsletter signup. The brand's category pages, such as the aluminum sheet and plate guide covering alloys 1050, 1060, 1350, 1070, 3003, 5052, and 6061, echo the non-magnetic properties we've discussed. For copper alloys, they point to the machining guides for C11000, C36000, and C93200, which underline the same non-magnetic, corrosion-resistant character. Use these resources to verify availability, then apply the magnet test on the incoming shipment to confirm the shipment is what you ordered. If a part you intended to be non-magnetic grabs the magnet, your supplier may have substituted a ferritic grade—catch it before it goes into your assembly.
Here is the verdict: iron, nickel, cobalt, and their alloys—carbon steel, cast iron, and many tool steels—stick to a magnet. Aluminum, copper, brass, and bronze do not. Stainless steel depends on its crystal structure: ferritic and martensitic grades stick, austenitic grades generally don't, but cold working can raise a weak pull in the austenitic family. Use a magnet as a quick sorting tool, but confirm with alloy markings or a datasheet for critical parts. The boundary line is the one between magnetic service, where you need that attraction, and non-magnetic service, where you must keep fields clear.
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