What are the solutions to the causes of broken head at the weld of excavator piston rod? It is best to use double shielded welding or 5O6 for manual welding. What should I pay attention to during welding? 1. Analysis: The stress on the piston rod weld is mainly tensile force, pressure and small shear force (if assembled, the shear force should be very small), which should be repeated load and cyclic change, and the metal has a fatigue tendency; 2. Observe the fracture to see whether there are traces of welding defects such as incomplete penetration and whether the starting point of cracking is weld or heat affected zone, so as to provide basis for summary and improvement; 3. Welding process: No matter whether the piston rod is hollow or solid, it is necessary to groove to ensure penetration; Covered electrode's choice-it is estimated that the piston rod is made of medium carbon alloy steel, with high strength and great tendency of welding cracks. It is suggested to choose high-quality medium carbon alloy steel covered electrode, 3mm flux-cored wire as backing and 5mm coating, and make an agreement with the welder to ensure penetration and work efficiency; Covered electrode should be baked well. Before welding, the groove and heat affected zone shall be cleaned of rust, oil, water and other sundries. It is suggested that the preheating temperature should be controlled at about 400 degrees Celsius, the welding should be completed at one time, and the coating should not fall off after welding, so it should be covered with thick asbestos cloth and cooled slowly. If this treatment is still unsatisfactory, it is suggested to use stainless steel alloy covered electrode to improve toughness, impact resistance, strength and weld strength. Welding process can refer to the above essentials, and the cost will be higher. Affirmation: All the above are written by myself according to my own experience, and I have no practical experience in repairing the broken welding of excavator piston rod. For the purpose of communication, I believe it can be improved step by step. For reference.