Special Substrate Metals

Some vehicle manufacturers use special or alternative metals in the construction of their vehicles. When possible, parts made from one of the seven listed metals will be identified using the abbreviations shown below.

It is not always possible or practical to identify where special or alternative metals are used on a vehicle. Do not assume that a part not identified as special metal isn’t actually made of special metal. When in doubt, it is recommended that you contact the vehicle manufacturer for further information. When performing repairs to special metal substrates, refer to OEM recommendations for specific information. Improper repairs may adversely affect the structural integrity and safety of the vehicle.

In instances where a component is comprised of multiple grades of material, MOTOR will indicate the highest-grade material used. Therefore, it is necessary to refer to the relevant OEM repair information to determine if component repair or replacement is required based on the precise area damaged.

ALUMINUM (ALU)

Aluminum is lighter than steel and is non-magnetic. Aluminum is sensitive to galvanic corrosion. Only use fasteners, tools and materials that are designated for use only on aluminum. Heat limitations MUST be observed when working with this type of metal. Variances can be found in alloy, strength, temper, and gauge properties. Such variations need to be considered prior to attempting a repair, and an on-the-spot evaluation is required. Aluminum component repair and/or replacement often requires specific equipment and tools. Always consult OEM repair procedures for vehicle-specific information.

BORON STEEL (BOR)

Boron steel has extremely high strength; do not use heat on this type of metal. It cannot be straightened because of the extremely high heat used in the forming process. The only solution for damage is replacement. Boron steel can be cut with a cutoff wheel. Drilling boron steel is very difficult and may be accomplished using a titanium drill bit combined with slow speed (490 rpm).

CARBON FIBER COMPOSITE (CFC)

Visible weave carbon fiber (non-painted) and non-visible weave carbon fiber (painted) parts are extremely lightweight and strong. Structural carbon fiber parts will require replacement if damaged. Manufacturers may have repair options for non-structural parts such as exterior panels, provided that the damage does not extend to an edge. Reparability options depend on the manufacturer's recommendations and procedures. Only use fasteners, tools and materials that are designated for use on carbon fiber.

High Strength Steel (HSS)

Generally, frame rails, inner rocker panels, suspension crossmembers, and upper apron rails are made of this material (this varies by manufacturer). Heat limitations MUST be observed when working with this type of steel. When in doubt, most manufacturers recommend all steel be treated as HSS steel.

HYDROFORMED STEEL (HYD)

Hydroformed parts may be sectioned depending on the vehicle manufacturer’s recommendation. Heat limitations MUST be observed when working with this type of steel.

MAGNESIUM (MAG)

Magnesium is much lighter, stronger, and more resistant to corrosion than steel. Magnesium has the tendency to crack or break either from collision damage or during straightening due to its quick work-hardening characteristics. Magnesium is also not weldable with common collision repair facility GMA (MIG) welding capabilities. Do not use oxyacetylene equipment or plasma arc cutting equipment around this or any other magnesium part. If magnesium catches on fire, it requires a class D fire extinguisher

SANDWICHED STEEL (SAS)

This type of steel (OEM’s may have other names) is being used on the dash panels, floor panels and oil pans etc. This product has an engineered non-steel layer sandwiched between two cold rolled layers of steel; do not use heat on this type of metal unless otherwise recommended by OEM. It is used to help lower sound levels and vibration. This product may or may not be weld-able with common collision repair facility GMA (MIG) welding.

SHEET MOLDING COMPOUND (SMC)

A high strength glass-reinforced thermoset molding material which is normally compression-molded and is used on some vehicle body outer panels and radiator supports. Manufacturers may have repair options for these types of non-structural parts. Reparability options depend on the manufacturer’s recommendations and procedures. Only use materials that are designated for use on sheet molded compounds.

STAINLESS STEEL (SSA):

Stainless steels are steel alloys that are very well known for their corrosion resistance, which increases with additional chromium content. Corrosion resistance may also be enhanced by nickel and molybdenum additions. Cosmetic repair to panels and paintless dent repair techniques are an acceptable method for repairing cosmetic panel damage. OEM repair guidelines should be followed.

ULTRA HIGH STRENGTH STEEL (UHS)

Generally, door guard beams, bumper reinforcements and other special purpose areas contain this type of steel. These parts must not be repaired. They are to be replaced only. Contact the vehicle manufacturer for applicable locations. This information supersedes information published in previous Guide to Estimating pages.

NOTE: Due to space limitations, special substrate metals information is not available in MOTOR CEG Online or DVD products.