Large-scale frame welding machining is a common product in large-scale machining at present. When performing large-scale frame welding machining, we should not only know the machining requirements of frame welding machining, but also know the technical requirements of large-scale frame welding. What are the technical requirements for welding?
- 1. The position of the welding port of the frame should avoid the stress concentration area and facilitate the welding process.
- 2. The groove of the steel structure should be processed in accordance with the machining drawings. When the drawing is not specified, the style and size of the groove should be selected according to these principles: to ensure the welding quality, the amount of filler metal is small, easy to operate, and to reduce welding stress and deformation.
- 3. Before assembling the welded parts of the frame, the oil, paint, scale, rust, burrs and galvanized layer on the surface of the welded joint and its vicinity should be cleaned to expose the metallic luster.
- 4. When the local gap of the welding port of the frame is too large, try to trim it to the specified size, and it is strictly forbidden to add stuffing in the gap.
- 5. The welding rod, welding wire and flux used in the welding process of large racks should be stored in a dry, well-ventilated place with a temperature greater than 5°C and a relative air humidity less than 60%. Welding rods for welding important parts should be stored in a special heat preservation cylinder at a temperature of 100-150℃, and taken as needed.
- 6. When the frame is welded and assembled, the workpiece should be firmly cushioned to prevent deformation and additional stress during welding and heat treatment.
- 7. Except for the cold-drawn joints specified in the design of the frame, the other weld joints are forbidden to use strong pairing, and it is not allowed to use the thermal expansion method to match the joints to prevent additional stress.
- 8. To ensure the welding quality of the frame, the welding place should be protected from wind, rain, snow and cold.
- 9. Welding parts that require preheating and post-weld heat treatment should be prepared for pre-heating and post-heating tooling equipment, temperature measuring instruments and thermal insulation protection products before welding.
- 10. When welding the welds on the plane, ensure that the longitudinal welds and the transverse welds (especially the transverse) can shrink freely. If welding butt welds, the welding direction should point to the free end.
- 11. When welding the frame, weld the welds with larger shrinkage first. If there are butt welds and fillet welds in the structure, weld the butt welds with larger shrinkage first.
- 12. When welding the frame, the short transverse weld should be welded first.
- 13. During the welding process of the frame, the welds with greater stress are welded first, so that the internal stress distribution is reasonable.
- 14. For the welding parts of the frame with large deformation, the welding reinforcement can be reasonably used according to the actual situation when welding.
- 15. Assembled welding parts composed of multiple components should be assembled and welded step by step, and the overall assembly welding process should be carried out after the deformation is corrected.
- 16. After the welding of the frame is completed, the entire internal and external surfaces or part of the frame should be corrected and cleaned.
- 17. The surface cleaning of the frame after welding should be shot peening, which can better improve the fatigue strength of the frame.
The above 17 are the technical requirements for welding of large frames. Welders should pay attention to these technical requirements when welding large frames to better improve the quality of frame welding. PTJ Machining is a large-scale mechanical machining factory specializing in large-scale frame welding machining and large-scale CNC gantry milling machining. Welcome to make drawings and samples!
Link to this article: The Technical Requirements For Large Frame Welding
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