Identification of Frame Rail Material

Chassis are manufactured with frame rails of different alloy steels and some are heat-treated. A factory reinforced frame is optional. Each material must be handled in a specific manner to assure maximum service life; therefore, the frame material must be determined before attempting repair or modification.

Chassis are presently manufactured with frame rails of:

• HSLA (high-strength low alloy) steel
• Heat-treated steel

The frame rail material can be determined by inspecting the frame and consulting the dealer vehicle line setting ticket and the sales data book.

Heat-treated rails are marked on the inside of the section with a decal which cautions against welding, flame cutting or the addition of holes in critical zones. These practices are restricted for all frame rails, however, heat-treated rails are much more sensitive to these alterations.

In either case, welding must be held to a minimum during repair to reduce welding heat-effected zone. For additional information, refer to: Frame Repair and Reinforcement .