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Cladding Metals: New Processes for a Centuries-Old Technique

The cladding of metals is a centuries-old metalworking technique From its origin as process for bonding decorative gold or silver surfaces on base metals, the cladding process has been refined to the point where today it is a sophisticated technology used in hundreds of industrial applications.


A clad metal is two or more distinct metals or alloys metallurgically bonded together in layers. At Engineered Materials Solutions, Attleboro, Mass., this bond is achieved by a refined process based on the technology of solid-state welding. This bonding technique is so effective there is no need for intermediate brazing alloys or adhesives. It's simple, clean and permanent.


Virtually any combination of ductile metals can be clad-with individual components representing from 2 to 98 percent of the total composite thickness. As a rule of thumb, composite properties, such as tensile strength and conductivity, can be estimated as the arithmetic sum of the volume percent of each component times its specific property value. Dimensions of EMS manufactured clad metals range from 0.00157 to 0.150 inch (0.039 to 3.8 mm) in thickness and up to 25 inches (635 mm) in width.


Clad metals can be made by several distinct processes. The principal method of manufacture used by Engineered Materials Solutions is a continuous roll bonding process in which two or more strips can be clad. Prior to bonding, the individual strips are extensively cleaned to provide contaminant-free surfaces. When passed through a specially designed rolling mill, a composite material is formed deriving its bond integrity from the creation of shared electrons between the mating surfaces. Subsequent thermal treatment is then done to induce diffusion, improve bond strength and provide stress relief for further cold-working operations. It should be noted that after bonding, the ratio of component materials remains constant throughout all cold-work operations.


Once the clad composite has been created, finishing operations are performed, such as rolling to intermediate and final gauge, annealing to temper, cleaning, buffing (if luster is critical), edge trimming and slitting prior to final shipment.

The objective of cladding is to provide in a single material the optimum combination of functional properties needed for a particular product. Careful selection of component materials and control of properties can result in significant improvements in product performance and reductions in product costs. The key is to approach clad metals from the perspective of combining the desirable properties of different materials for the specific product application.


Some typical applications for clad metals are:

Architectural metals
Bearing materials
Bright truck bumpers
Button cell battery cans
Cable shielding
CATV wire
Catalytic converter substrate
Heat exchangers
Self-brazing materials
Thermostat bimetal (thermal actuators, motor protectors, fluorescent light ballasts, etc.)
Transition material


Todd W. Romance is vice president of sales and marketing and new product development for Engineered Materials Solutions, Attleboro, Mass. He has spent most of his career in the specialty chemicals and metals markets. Prior to joining EMS, Romance was vice president and general manager of the Cobalt Division of OMG in Cleveland.