Friction welding of .gamma. titanium aluminide to steel body with nickel alloy connecting piece there between

A process for producing a component comprising a body composed of an alloy based on a gamma-titanium aluminide, a steel body and a connecting piece composed of a nickel-base alloy, by means of which connecting piece the gamma-titanium aluminide body and the steel body are rigidly joined to one another, the joint between the gamma-titanium aluminide body and the connecting piece being produced by friction welding, the method comprising steps of:

• selecting a nickel-base alloy containing
• ______________________________________ 18-20 percent by weight of chromium, 18-22 percent by weight of iron, 2-4 percent by weight of molybdenum, 4-6 percent by weight of niobium, up to 1 percent by weight of aluminum, up to 2 percent by weight of titanium, up to 0.4 percent by weight of silicon, up to 0.4 percent by weight of manganese, up to 0.05 percent by weight of carbon, and unavoidable impurities and nickel as the remainder;
• ______________________________________
• first rotating the gamma-titanium aluminide body and the connecting piece against one another during friction welding under a rubbing pressure which does not exceed a first limit value, and
• subsequently welding the gamma-titanium aluminide body and the connecting piece together at relative rest with respect to one another under an upsetting pressure, which does not exceed a second limit value which is higher than the first limit value, to form a diffusion layer containing at least titanium and aluminum.