4J29 is a typical Fe-Ni-Co hard glass sealing alloy, which has been used in aviation factories for a long time and has stable performance. The oxide film of the alloy is dense and can be well infiltrated by glass. It is the main sealing structural material of the electric vacuum device, mainly used for the glass sealing of the electric vacuum components such as the transmitter tube, the oscillation tube, the ignition tube, the magnetron, the transistor, the sealing plug, the relay, the lead line of the integrated circuit, the chassis, the shell, the bracket, etc.