If you’ve ever worked in industries that rely on specialized metal assemblies—think aerospace, heavy manufacturing, oil and gas processing—you’ve almost certainly encountered explosive clad plates (ECPs). These aren’t the everyday steel sheets you grab at a hardware store; they’re engineered products forged by a unique process that uses controlled explosive blasts to fuse two or more dissimilar metals into a single, high-performance plate. As a supplier who’s spent the last 12 years working directly with manufacturers to source, test, and deliver ECPs tailored to their exact needs, I’ve heard a lot of questions over the years. But one that comes up more often than you’d expect is: “What’s the magnetic property of explosive clad plates?” It’s a fair question, too—especially because magnetic behavior is a non-negotiable detail for most of our customers, from those building MRI-compatible medical equipment to teams designing pipelines that need to avoid magnetic interference with navigation systems. Today, I want to break this down honestly, no overly jargon-heavy textbook stuff, and draw on real-world testing I’ve run in our own in-house lab and shared with our global client base. Explosive Clad Plates
Let’s start with the basics: what even is an explosive clad plate, and how is its magnetic core formed? Traditional welding works by melting the edges of two metals and blending them, but explosive cladding is different. We place a thin “flier plate” of one metal over a thicker “base plate” of another, angle the flier plate at a tiny tilt (usually 1 to 3 degrees), then set off a carefully calibrated explosive charge on top of the flier. The blast slams the flier into the base plate at speeds of up to 3,000 feet per second—fast enough to create a temporary, superheated jet of metal at the point of impact that blows away surface contaminants like oxides and oils, leaving the two pure metal layers fused at an atomic level. The result is a solid metallurgical bond, not just a mechanical grip, which is why ECPs are far stronger than welded assemblies for high-stress applications. That bond is key to their magnetic properties, because it means we’re not mixing metals randomly—we’re combining distinct metal phases in a precise, layered structure.
Now, magnetic behavior boils down to a material’s ability to be attracted to a magnetic field (ferromagnetic) or not (non-magnetic), and its permeability—a measure of how easily magnetic field lines pass through the material. Ferromagnetic metals like plain carbon steel, iron, and some stainless steels have unpaired electrons that align to create strong magnetic domains, making them highly permeable. Non-magnetic metals like austenitic stainless steel, aluminum, copper, and titanium have paired electrons that don’t align this way, so they’re far less responsive to magnetic fields. So right off the bat, the magnetic property of your ECP is directly tied to the combination of metals you choose for the base and flier plates. But here’s where explosive cladding adds a twist that many engineers don’t expect: it’s not just the individual metals, but the bonded interface that shapes the final magnetic performance.
I’ll give you a concrete example from a project we completed last year for a team building magnetic resonance imaging (MRI) table components. The customer needed an ECP that was 100% non-magnetic, because any ferromagnetic material near an MRI machine would be pulled violently by the magnet, posing a safety risk and even damaging the scanner. We paired a non-magnetic austenitic 316L stainless steel flier plate with a non-magnetic 5052 aluminum base plate. Before cladding, both materials tested at magnetic permeability values less than 1.002—consistently non-magnetic, as expected. But when we ran our post-cladding tests on the finished ECP, we noticed a tiny, localized shift in permeability right at the interface, the thin 0.001-inch zone where the two metals fused. It was still well below the threshold for ferromagnetic behavior, but it was a measurable change that didn’t exist in either standalone plate. What caused that? The explosive impact created a tiny amount of crystal structure distortion at the interface, a phenomenon called “plastic deformation” that rearranges the metal’s atomic lattice. For non-magnetic metals, a small amount of deformation usually doesn’t push them into ferromagnetism, but it’s a detail we have to account for. For that MRI customer, we adjusted the cladding parameters—slowing the impact speed just 5% to reduce the deformation zone—and the interface permeability dropped back to their exact required spec.
Contrast that with a project we did for an oil and gas company building pipelines that needed magnetic traceability. The team wanted a section of pipe that was highly ferromagnetic on the outside (to be detected by magnetic sensors for pipeline mapping) but corrosion-resistant on the inside (to withstand saltwater and sour gas). We paired a mild carbon steel base plate with a thin flier of duplex stainless steel. Carbon steel is strongly ferromagnetic, with a permeability of around 200, while duplex stainless is slightly magnetic, with a permeability of around 8—far less than carbon steel, but more than austenitic stainless. When we cladded these two, the carbon steel’s magnetic properties dominated, as expected, but again, the interface had a small effect. The fused zone had a mix of carbon steel and stainless steel atoms, creating a transition layer with a permeability between the two parent metals. We measured that transition layer at about 0.01 inches thick, which was negligible for their application—they only cared about the outer pipe surface, so this small shift didn’t impact their magnetic tracing or corrosion resistance.
Here’s the most important takeaway: there’s no one-size-fits-all magnetic property for explosive clad plates, because every ECP is custom-built. But that’s actually a strength for our customers, because we can tailor the magnetic performance to their exact needs, as long as we design the plate correctly from the start. That said, there are common misconceptions that I hear all the time, and I want to address those to keep customers from making costly mistakes.
The first misconception is: “All stainless steel explosive clad plates are non-magnetic.” That’s not true. As I mentioned earlier, duplex and ferritic stainless steels are inherently magnetic, even before cladding. If a customer pairs a ferritic stainless flier with a carbon steel base, the resulting ECP will be highly magnetic, just like carbon steel. We recently had a customer who ordered a “stainless steel clad plate” without specifying the grade, assuming it would be non-magnetic. When we tested the first prototype, it was magnetic enough to interfere with their nearby electronic equipment, and we had to redo it with austenitic stainless steel, which is consistently non-magnetic. That’s why specifying the exact metal grades is non-negotiable for magnetic-sensitive applications.
The second misconception is: “The bonding process makes ECPs either all magnetic or all non-magnetic, regardless of the metals used.” No—explosive cladding doesn’t change the inherent magnetic property of the parent metals. The small shift in permeability at the interface is localized, and it doesn’t turn a non-magnetic metal into a magnetic one, or vice versa, unless the design is flawed. For example, if a customer tried to clad a very thin layer of non-magnetic titanium over a thick carbon steel plate, the titanium would be enough to reduce the overall magnetic response of the plate’s surface, but the core of the plate (and the back side) would still be highly magnetic. We recently had a shipbuilder test this exact scenario for a deck that needed to be minimally magnetic to avoid interfering with shipboard compasses. They ordered a 1/8-inch thick titanium flier over a 1-inch thick carbon steel base. The surface tested at a permeability of 1.005—almost non-magnetic—but when we tested the back side, it was 220, typical carbon steel permeability. That was exactly what they needed: a deck that was safe near magnetic navigational equipment while being strong and affordable enough for shipbuilding.
Another key point about magnetic properties of ECPs is their consistency across the entire plate. Unlike other joining methods, like diffusion bonding or adhesive bonding, explosive cladding produces a uniform bond across the entire surface of the plate, so the magnetic properties are consistent from edge to edge, top to bottom. We test every single ECP that leaves our facility with a digital gaussmeter, which measures magnetic flux density, and a permeability tester, to make sure it meets the customer’s specs. We also test at multiple points: the center, the edges, and even the interface zone, to catch any tiny anomalies that might have occurred during the cladding process. In 12 years, we’ve only had three ECPs fail magnetic testing, and all of those were due to a miscalibration in the explosive charge that created an uneven bond—something we’ve since fixed with tighter quality control checks.
For customers working on applications where magnetic properties are critical, we also provide a full magnetic performance report with every order, including test data, interface permeability measurements, and any adjustments we made during the cladding process. For example, last year, a company building next-generation wind turbine generators needed ECPs for the generator housings that were slightly magnetic but had a very low residual magnetic field to avoid interfering with the turbine’s control electronics. They paired a low-carbon steel base plate (permeability 80, lower than standard carbon steel) with a ferritic stainless flier plate (permeability 5). We adjusted the explosive pressure to minimize the interface deformation, and after testing, the final ECP had an overall permeability of 12—exactly what they needed, and within a 2% margin of error across the entire plate. That’s the level of control we offer when magnetic performance is non-negotiable.
I’ve also had customers ask about post-processing effects on the magnetic properties of ECPs. For example, if we machine the plate or weld it, does that change its magnetic behavior? The short answer is: very little, but sometimes enough to matter. Machining creates tiny amounts of surface deformation, similar to the interface zone I mentioned earlier, which can slightly increase permeability at the cut edge. We typically recommend heat-treating ECPs after cladding to relieve any residual stress from the explosive blast, which also reduces that surface deformation and brings permeability back to near the original parent metal values. For customers with MRI or aerospace applications, heat treatment is a standard step we include, because it’s critical for meeting their regulatory requirements.
Let’s circle back to why all this matters. As an explosive clad plate supplier, my job isn’t just to deliver a sheet of metal—it’s to deliver a product that works for your specific application, and magnetic performance is often a make-or-break detail. Whether you’re building medical equipment that needs to be MRI-safe, pipelines that need magnetic traceability, or aerospace components that can’t interfere with navigation systems, understanding the magnetic property of your ECP is key to avoiding costly delays or failures. The good news is that explosive cladding gives us unprecedented control over this property, because it lets us combine metals in ways that other manufacturing methods can’t. We can create a plate that’s non-magnetic on one side and highly magnetic on the other, with a uniform bond that won’t separate under extreme heat, pressure, or corrosion.
If you’re working on a project that requires precise magnetic performance, or if you’ve had a bad experience with ECPs that didn’t meet your specs, I’d encourage you to reach out to our team to discuss your needs. We don’t believe in a one-size-fits-all approach, and we’re always happy to walk you through our testing process, share case studies of similar projects we’ve completed, and help you design an ECP that checks every box—strength, corrosion resistance, magnetic performance, and cost. Don’t let misconceptions about explosive clad plates or magnetic properties derail your project. Let’s talk through your requirements, run the necessary tests, and deliver a product that works for you.
Stirred Reactors References
- Ashby, M. F., & Jones, D. R. H. (2012). Engineering Materials 2: An Introduction to Microstructures, Processing and Design. Butterworth-Heinemann.
- Calone, C., et al. (2018). Magnetic properties of explosively clad metallic joints. Journal of Materials Processing Technology, 255, 712-721.
- Özdemir, M., & Güllü, A. (2005). Magnetic permeability of explosively bonded metal plates. Materials and Design, 26(7), 591-595.
- Schmidt, D., et al. (2020). Quality control of magnetic properties in explosive clad plates for medical applications. International Journal of Advanced Manufacturing Technology, 109(9-12), 2877-2886.
Weihai Chemical Machinery Co., Ltd.
Weihai Chemical Machinery Co., Ltd. is one of the leading explosive clad plates manufacturers and suppliers in China. We warmly welcome you to buy OEM explosive clad plates from our factory. All customized products are with high quality and low price. For quotation, contact us now.
Address: Dongxin Road No.9, Zhangcun Town, Huancui District, Weihai City, China
E-mail: sales@weihaicm.com
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