Does Stainless Steel Set Off Metal Detectors?

Most of the time, stainless steel does not set off metal detectors, including the walk-through scanners at the airport. The common food- and jewelry-grade stainless steels (austenitic grades like 304 and 316) are only weakly magnetic and conduct electricity relatively poorly, so small, thin items such as a ring or a watch back often pass through unnoticed. Larger or thicker stainless objects, though, carry enough metal to trip a sensitive scanner.

Stainless steel is still an iron-based (ferrous) alloy. It isn’t “non-magnetic metal” the way aluminum or copper are. What makes the everyday grades hard to detect is their low magnetic permeability, not a lack of iron.

What Is A Metal Detector?

A metal detector is an electronic device that senses the presence of metals. They can find hidden metal objects in public spaces and underground. They work by having a sensor that emits an electromagnetic field and creates an alarm sound when it comes across metallic objects.

What Metals Can Be Detected By A Metal Detector?

Metal detectors easily detect ferrous metals.

These metals contain iron or iron components, and their magnetic and electric properties are active, which makes them easy to detect.

Here’s the list of metals that a metal detector can detect:

• Carbon steel (where carbon is the primary alloying element and may contain other elements)
• Cast iron
• Wrought iron

Metals That Can’t Be Detected

Metal objects that are too thin or soft go undetected by metal detectors. Usually, metal detectors do not pick up jewelry, which includes gold, silver or platinum, if they are really small in size.

However, there are metal detectors capable of picking up many types of metals. The process of making a detector pick up different target metals is called discrimination. For instance, an audio-type discriminator can be programmed to emit sound signals to pick up metals like nickel.

Further, detectors do not detect non-ferrous metals easily because of the low magnetic field they produce. Since Titanium is a non-ferrous metal, it does not trigger an alarm in the detector.

Stainless steel is harder for many detectors to pick up because the common austenitic grades have low magnetic permeability and don’t conduct electricity as well as metals like copper or brass. That means it responds only weakly to the field created by detectors.

Does Stainless Steel Set Off Metal Detectors?

Stainless steel has very low electrical conductivity and low magnetic properties. So airport metal detectors usually don’t detect stainless steel easily. That said, some metal detectors will have the capacity to detect stainless steel if their sensors are configured correctly.

A metal detector produces an electromagnetic field around it. The field energizes any metal plate material in the region of the detector. Since stainless steel does not conduct electricity well, it fails to get energized by the field. As a result, the detector is unable to detect it.

Ferrous metals are those which contain iron or iron components. They conduct electricity well and have good magnetic properties. So these are easy for detectors to pick up.

Non-ferrous metals contain no iron and are non-magnetic. Some examples include copper, aluminum, lead, brass etc.

What is the difference between Steel and Stainless Steel?

Carbon steel and stainless steel are the two major types of steel. The former is more generally referred to as steel and may come in various forms.

Carbon steel includes a large number of steel alloys containing iron and 0.12 to 2% carbon. Within this short carbon content range, the steel varies significantly in terms of properties, especially hardness.

High carbon steels show excellent hardness, and abrasion resistance, allowing them to stand high magnitude forces.

Stainless steel, on the other hand, contains carbon, iron, and 10.5% chromium. More elements, like nickel, molybdenum, and manganese, can add further mechanical and corrosion resistance properties.

Chromium is the crucial component of stainless steel because it forms a layer of oxide that protects its surface from corrosion. Further, the same layer protects stainless steel from rusting.

Do Body Piercings Set Off Metal Detectors?

No!

Body piercings do not trigger metal detectors.

Will an Artificial Joint Set Off a Metal Detector?

A majority of artificial joints and implants (such as what’s used in a hip replacement) will set off a metal detector. Nowadays, many orthopedic implants contain plastic and ceramic in addition to metals. So the metal will mostly raise the alarm of the metal detector.

Frequently asked questions

Does stainless steel set off airport metal detectors?

Usually not for small items. A stainless steel ring, watch, or belt buckle typically passes through an airport walk-through detector without an alarm, because everyday stainless grades have low magnetic permeability. Bigger or denser items (a full-size water bottle or a laptop stand, say) have enough metal mass to trigger it, and they’ll be screened anyway.

Will brass set off a metal detector?

Yes, usually. Even though brass is non-magnetic, it’s a good electrical conductor, so walk-through and handheld detectors pick it up readily, often more easily than stainless steel of the same size. Only very small brass items are likely to slip past.

Does a stainless steel water bottle set off metal detectors?

A full-size stainless steel bottle is large enough that a sensitive detector can register it. At the airport it’s a moot point, since bottles have to come out for screening regardless, but for a simple walk-through detector, a big empty bottle may or may not alarm depending on the machine’s sensitivity.

Does steel set off metal detectors more than stainless steel?

Generally yes. Plain carbon steel is strongly magnetic and iron-rich, so it responds strongly to a detector’s field and is easy to pick up. The common stainless grades used in bottles and jewelry are much less magnetic, which is exactly why they’re harder to detect.

Shape and manufacturing also matter: compare how stainless steel behaves when it is bent and formed and why some jewelry grades are better for sensitive skin.