The manufacturer of the telescopic arm of excavator introduces the maintenance of the lengthened arm for you. Moving arm repair: When inspecting the corrosion cracks on the side plate of excavating motor arm, it is necessary to scrape or polish the paint layer or rust on the surface of the cracks. When observing, it is necessary to tap the weld with a hammer and use a magnifying glass when necessary.
1. Causes of cracks
Causes of cracks in side plates of mine mobile arms include air bubbles, small cracks and slag inclusion in the original weld seam. When the excavator is overworked, the original weld seam will produce small cracks and gradually expand. When the welding rod meets the performance and cracks of the plate, it is difficult to use reliable and effective thermal insulation measures due to large mining mobile arms, and after welding, it will be thorough. Removing the hardening zone around the weld leads to the decrease of welding strength: vibration has a greater impact on excavator operation, and uneven weld cracking.
2. Repair methods
Pre-welding preparation: Use hand grinding wheel to clean up the oil, paint and rust on the crack of the original weld. The weld crack is scraped to the side plate body by air planer, and the hardened area of the previously welded base material is cleaned up. After plane cutting, grind the incision with angle grinding wheel (inner surface is grinded into v-groove), clean it, check pink, confirm that all cracks have been found and cleaned.
根据维修的现有条件,选择Φ5毫米E5015模型(J507)或E5016 J506焊条,烘烤2 h温度低于350℃,在100℃保温,防止电极吸收水分,带上。焊接电流190 ~ 230A。由于挖掘机侧板厚度较大，焊接部分焊接前预热至150 ~ 250℃;在焊接过程中，可采用分段法、对称法和反推法。在焊缝冷却过程中，焊缝金属应不断用手锤敲击以消除应力。在侧板角焊时，为了避免电弧缺陷，应连续焊接，以改善接头的受力状态。
According to the existing conditions of maintenance, choose 5mm E5015 model (J507) or E5016 J506 welding rod, bake for 2 hours at less than 350 C, heat preservation at 100 C, prevent the electrode from absorbing moisture, take on. Welding current 190 - 230A. Because of the large thickness of excavator side plate, the welding part is preheated to 150 ~ 250 C before welding. In the welding process, segmented method, symmetrical method and back-stepping method can be used. During the cooling process, the weld metal should be hammered continuously to eliminate the stress. In side plate fillet welding, in order to avoid arc defects, continuous welding should be carried out to improve the stress state of the joint.
After welding, spatters, welding slag and welding nodules should be thoroughly removed, and the weld height should not be greater than 2.5mm. The weld shall be inspected by magnetic powder and shall not have defects such as cracks.
3. Grade Corrosion Measures
Thoroughly polish the weld seam, remove rust stains, and apply anti-rust paint. In the excavation construction site, for the existing corrosion welds, manual rust removal can be selected according to the actual excavation situation. Pickling and rust removal can also be used. Organic acid is also used as the main household. With corrosion inhibitors, surfactants, rust removal agents, rust inhibitors, rust inhibitors and film forming agents and other composite materials, the purpose of rust removal and rust prevention can be achieved by cleaning with rust removal function and rust-proof primer pickling solution.
In addition, attention should be paid to keeping excavators in a clean and dry environment, maintaining good ventilation and eliminating corrosive gases and moisture in time.