GM Takes Multi-Material Approach with Cadillac CT6

General Motors Co. says it will use 13 different materials to cut the weight of its upcoming CT6 large sedan by 198 lbs (90 kg) compared to a traditional steel architecture.

The all-new car will debut next month at the New York auto show. Production is set to start late this year at GM's Detroit-Hamtramck assembly plant.

Nearly two-thirds of the CT6's structure and all its exterior body panels are aluminum. The car's lower structure consists of 13 high-pressure die cast aluminum components assembled in combination with aluminum sheet and aluminum extrusions, plus steel close-out panels to reduce in-cabin noise.

The occupant safety cage consists of high-strength aluminum reinforced with strategically placed high-strength steel. The B-pillars are made entirely of steel. Both materials are used in combination in the car's front and side impact zones.

The metal components will be assembled using aluminum spot welds, steel spot welds, flow drill screws, self-piercing rivets, laser welding, aluminum arch welding and structural adhesives. The resulting structure has high mass efficiency and the best torsional rigidity of any Cadillac, according to GM.