Hitachi 350 Boom Rod End Welding
Boom rod welding on Hitachi 350 excavators is a process used to repair wear or cracks in the boom’s basic connection points. The boom rod is under constant stress as it provides the connection between the boom and other moving parts, so damage can occur over time.
Here is a detailed guide on how to perform this process:
1. Safety and Preparation
Secure the Machine: Secure the excavator on level ground and completely shut down the engine.
Relieve Pressure: Prevent accidents by completely draining the hydraulic system.
Use Protective Equipment: Wear goggles, gloves, and proper clothing when welding.
2. Damage Detection
Check for Wear or Cracks:
Check the boom rod bores for ovality, cracks, or deformation.
Inspect the connecting pins and bushings.
Precision Measurement:
Measure the inside diameter of the rod bore and compare it to factory tolerances.
If out of tolerance, welding and machining will be required.
3. Disassembly
Remove Boom Rod: Carefully remove pins, bushings and links.
Separate Worn Parts: Completely remove deformed or damaged parts.
4. Weld Preparation
Cleaning:
Remove oil, rust and dirt from the surface of the housing.
Smooth the surface with a grinding tool.
Pre-welding Inspection:
Make sure that the cracks are completely cleaned.
Select the appropriate welding electrode or filler material (for example, an electrode suitable for low alloy steels).
5. Welding Application
Fill Welding:
Fill the cracks with the appropriate welding method (MIG, TIG or stick welding).
Achieve a smooth surface by grinding between layers.
Slot Remachining:
After welding, machine the housing on a lathe or milling machine to restore factory dimensions.
6. Part Assembly
Installing New Bushing and Pin:
After machining the socket to the correct dimensions, place the new bushes and pins in place.
Tightness of Connections:
Install all connections tightly and make sure that the moving parts work properly.
7. Final Checks and Test
Fill the Hydraulic System:
Add the appropriate hydraulic oil to the system and test the pressure.
Operation Test:
Test the excavator's boom movements at low speed to see if there is any problem.
Important Notes
Welding operations must be carried out precisely and accurately, otherwise the structure integrity may be compromised.
Carefully manage the process to reduce the thermal stresses generated during welding.
If the damage is extensive or you do not have sufficient equipment for welding, consult a professional welding shop.
By following these steps, you can safely and effectively repair the boom rod of Hitachi 350.
