Inspect the excavator boom side plate weld for rust and cracks.

When inspecting for rust and cracks in the excavator boom side plate welds, the paint layer and rust on the weld surface must be scraped off or thoroughly ground away. During inspection, lightly tap the weld with a small hammer, and if necessary, use a magnifying glass to examine it closely.
1. Causes of Cracking
Reasons for cracking in the excavator boom side plate: These include inherent gas porosity, slag inclusion, and minute cracks present in the original weld seam itself. When the excavator operates under overload conditions, these microscopic cracks at the weld site gradually expand over time. Additionally, cracks may form due to mismatches between the welding rod and the base material properties during the welding process. Given the large size of the excavator boom, it is challenging to implement reliable and effective heating or heat preservation measures post-welding. As a result, the hardened zone around the weld area often remains partially intact after welding, leading to reduced weld strength. Finally, the significant vibration and impact forces generated during excavator operation cause uneven stress distribution at the weld joint, ultimately resulting in weld cracking.
2. Repair Methods
Pre-weld preparation: Use a handheld grinding wheel to thoroughly remove oil stains, paint, rust, and other contaminants from the original weld crack area. Next, use an air chisel to carefully gouge out the weld crack, extending the cut all the way into the base material of the side plate. Be sure to completely eliminate any previously hardened areas caused by prior welding. After gouging, smooth the cut edges using an angle grinder (creating a V-shaped bevel on the inner interface). Finally, clean the area, perform a dye-penetrant inspection, and confirm that all cracks have been fully identified and removed.
Based on the available repair conditions, select Φ5mm welding electrodes型号 E5015 (J507) or E5016 (J506). Bake them at 350°C for 2 hours, then keep them warm at 100°C to prevent moisture absorption—take out only as needed. Use a welding current of 190–230A. Since the excavator side plates are relatively thick, preheat the welding area to 150–250°C before starting the weld. During the welding process, adopt a segmented, symmetrical, and back-stepping technique. Additionally, while the weld cools, continuously tap the weld metal with a hand hammer to relieve residual stress. When welding at the corners of the side plates, to avoid arc-starting and arc-ending defects, it’s recommended to perform continuous welding, thereby enhancing the structural integrity and load-bearing capacity at the joint.
After welding is completed, thoroughly remove spatter, slag, and weld beads. The excess height of the weld shall not exceed 2.5 mm. Perform magnetic particle inspection on the weld; no defects such as cracks are allowed.
3. Measures to Prevent Weld Seam Corrosion
Thoroughly grind, remove rust from, and apply anti-rust paint to the weld seams. At excavation construction sites, for existing rusted welds, workers can manually remove rust based on the actual situation. While this method reduces labor intensity compared to other approaches, it still results in higher labor costs. Alternatively, acid pickling can be used—a technique that employs organic acids as the primary ingredient, combined with corrosion inhibitors, surfactants, rust removers, rust preventatives, and film-forming agents to create a composite solution. This solution not only effectively removes rust but also provides anti-rust protection and acts as a primer, achieving both rust removal and rust prevention through the cleaning process.
Additionally, during operation, care should also be taken to keep the excavator regularly in a clean and dry environment, ensuring adequate ventilation and promptly removing corrosive gases and moisture.