Abstract: The main parts of the lightweight gas casing are a rigid force-absorbing part (1) consisting of metal plates (2, 3) which can be worked without cutting, have flanges (4, 5, 6) for connecting the casing to fluid-conducting engine parts and are rigidly connected to one another, for example by welding. The channels (12, 16) are sheet metal pressed parts which connect to one another the through-holes (9, 11; 14, 15) in the flanges (4,5, 6), which form the inlet and outlet cross-sections of the fluids, and are welded by their ends to these through-holes.