Quality control method for inertial welding

In an inertial welding process of the type wherein, during each of the plurality of repetitive cycles, two workpieces are relatively rotated in rubbing contact at a common interface solely by means of a rotating inertial mass while being continuously pressed together, an improved method of maintaining quality control during repetitious cycles of said inertial welding process comprising the steps of:

• Monitoring the amount of relative axial movement between the workpieces after initial engagement of the workpieces to determine axial upset during the welding process;
• Comparing axial upset amount with an upset range predetermined as being representative of an effective bond between the workpieces.
• Producing a substantially instantaneous signal indicating correlation between the axial upset amount and the predetermined upset range;
• Monitoring the relative speed of rotation between the two workpieces and pressure under which the two workpieces are axially engaged, simultaneously with monitoring of axial movement between the parts;
• Comparing the relative speed of rotation and the axial pressure with respect to predetermined ranges which are representative of an effective bond between the work pieces;
• Producting substantially instantaneous signals indicating correlation of the monitored relative speed of rotation and axial pressure with the predetermined ranges for these conditions;
• Conditioning repetition of the welding operation upon maintenance of axial upset amount, relative speed and axial engagement pressure within their respective predetermined ranges during each cycle;
• Permanently recording axial upset amount, between the workpieces;
• and
• Displaying a continuous signal for each weld operation to indicate when axial upset amount is within and outside the predetermined upset range.