English Views: 122 Author: Site Editor Publish Time: 2021-12-30 Origin: Site
When inspecting the rusty cracks of the welding seam of the side plate of the bucket wheel excavator arm, which is connected with the bucket of excavator, it is necessary to scrape or polish the surface paint and rust of the welding seam. When observing, lightly hit the welding seam with a small hammer, and use a magnifying glass to observe if necessary.
Reasons for cracks in the side plate of the bucket shovel excavator arm: include bubbles, slag inclusions and micro cracks in the original weld itself. When the bucket chain excavator is overloaded, the original weld will produce micro cracks and slowly expand. Welding rod cracks caused by inconsistency with the performance of the plate. Due to the large size of the shaker bucket excavator arm, it is difficult to adopt reliable and effective heating and heat preservation measures. After welding, the hardened area of the base material around the weld cannot be completely removed, resulting in a decrease in the strength of the weld. During the operation of the articulating bucket excavator, the vibration and impact are relatively large, and the uneven force at the welding seam causes the welding seam to crack.
Preparations before welding: remove the oil, paint, rust, etc. from the original weld cracks with a hand wheel. Gouging away the weld cracks with gouging machine, gouging to the body of the side plate of the gummy bucket excavator, and clear the hardened area of the base material welded in the past. After that, use a corner grinding wheel to smooth the incision (the inner interface is polished to form a V-shaped groove). After cleaning and inspection, confirm that all the cracks on the mud bucket excavator have been found and removed.
According to the existing maintenance conditions, choose Φ5mm electrode type E5015 (J507) or E5016 (J506), bake it at 350°C for 2 hours, and then keep it at 100°C to prevent the electrode from absorbing moisture. Take it as needed. Set the welding current at 190～ 230A. Due to the large thickness of the side plate of the teeth bucket excavator, the welded part should be preheated to 150-250℃ before welding. During the welding process, the welding can be performed in sections, symmetrical, and backward. The hand hammer should be used continuously during the cooling process of the weld to strike the weld metal to eliminate stress. When welding at the corners of the side plate, in order to avoid arc defects, continuous welding should be applied to improve the stress condition of the joint.
After welding, completely remove spatter, welding slag and weld bead, etc., and the welding seam shall not exceed 2.5 mm in height. Magnetic particle inspection is carried out on the weld, and no defects such as cracks are allowed.
Thoroughly sand the weld, remove rust and apply anti-rust paint. In the excavation construction site, for the existing rusty welds, manual rust removal can be selected based on the actual situation. The disadvantage is that the labor intensity of the workers is relatively high and the labor cost is high; the pickling method can also be used to remove rust, that is, organic acid is used. The main base is equipped with composite materials such as corrosion inhibitors, surface activators, rust removers, rust inhibitors and film-forming agents to prepare a pickling solution with rust removal, rust prevention and primer functions.
In addition, during use, care should be taken to keep the excavator with bucket in a clean and dry environment, maintain good ventilation, and remove corrosive gases and moisture in time.
