Preliminary Requirements

Safety Requirements

WARNING

IT IS THE RESPONSIBILITY OF THE OPERATOR TO OBTAIN AND OBSERVE THE MANUFACTURERS MATERIAL SAFETY DATA SHEETS FOR CONSUMABLE MATERIALS INFORMATION SUCH AS, HAZARDOUS INGREDIENTS, PHYSICAL/CHEMICAL CHARACTERISTICS, FIRE, EXPLOSION, REACTIVITY, HEALTH HAZARD DATA, PRECAUTIONS FOR SAFE HANDLING, USE AND CONTROL MEASURES AND ALSO TO TAKE LOCAL REGULATIONS INTO CONSIDERATION.

Procedure

1. SUBTASK 70-39-02-300-001 General

   Hot squeeze riveting is used to shape rivets that do not give to cold working. An example for this procedure is for riveting bearing cages. It must only be used when specified in the Engine Manual.

   The equipment for hot squeeze riveting can be a resistance welding machine with applicable electrodes, if the necessary electrical current and pressure values can be made. Alternatively, there are available a number of machines specially made for this type of riveting.

   1. 
      CAUTION
      ALL ELECTRODES MUST BE MATTHEY 20W3 TIPPED.

      Matthey 20W3 is a sintered alloy of copper tungsten. It is available from Johnson Matthey Metal Joining, York Way, Royston, Hertfordshire SG8 5HJ.

      1. Hot squeeze riveting - riveting machine.

         1. Description.

            1. A riveting machine gives a low-voltage high-amperage electric current to heat the rivet shank while at the same time a pressure is applied to shape the rivet head. The electric current and the pressure are applied through an electrode which can be replaced.

            2. The control value necessary for any special job must be made by trial and error.

            3. An example of a hot squeeze riveting machine is shown in Figure.

      2. Hot squeeze riveting - resistance welding machine.

         1. Description.

         2. A resistance welding machine, with applicable electrodes, which gives the necessary electrical current and pressure values can be used for hot squeeze riveting.

         3. Tools necessary to adapt the machine will be specified in the Engine Manual.

         4. The control value necessary for any special job must be done by trial and error.

2. SUBTASK 70-39-02-390-001 Procedure Control

   1. Procedure control is by data sheet, the values of which have been made by test piece calculation by the use of correct sized rivets as specified in the repair scheme.

   2. Test piece procedure.

      1. Prepare.

         Test pieces must be near the rivet and hole size, and of the thickness and materials of component parts being attached. An example test piece is shown in Figure.

      2. Examine.

         Test pieces must be visually examined under low power magnification (up to x10) for the subsequent:

         1. Well shaped rivet head, has no defects.

         2. Has no cracks.

         3. Correctly aligned, ie rivet head in correct position.

         4. No sign of test piece buckling around the rivet head.

         5. No sign of dents on the preformed rivet head.

      3. Riveting faults.

         1. Misshapen rivet head can be caused by incorrect adjustment of electrode height or a rivet head not in line with the electrode gap.

         2. An incorrect current value can cause cracks to start.

         3. Defects on the rivet head can be caused by irregular defects on the electrode contact face.

         4. Buckling can be caused by too much electrode pressure or incorrect selection of rivet.

         5. Dents on the preformed rivet head can be caused by the incorrect location of the preformed head on the anvil, or the use of an incorrect anvil.

3. SUBTASK 70-39-02-210-001 Inspection

   1. Riveted components must be inspected with the applicable repair scheme.

Figure: An example of a Hot Squeeze Riveting Machine

An example of a Hot Squeeze Riveting Machine



Figure: An example of a Test Piece

An example of a Test Piece