1. The position of the frame welding interface should avoid the stress concentration area and be convenient for welding processing.
2. The groove of steel structure shall be processed according to the processing drawing. If there is no provision in the drawing, the style and size of the groove shall be selected according to these principles: ensuring the welding quality, less filler metal, convenient operation, reducing welding stress and deformation, etc.
3. Before assembly of the frame weldment, the oil, paint, dirt, rust, burr and galvanized layer on and near the welding interface surface shall be removed to expose the metallic luster.
4. If the local gap of the frame welding interface is too large, try to trim it to the specified size, and it is strictly forbidden to add filler in the gap.
5. The welding rod, welding wire and flux used for welding and processing of large frame should be stored in a dry place with good ventilation, temperature greater than 5 ℃, and relative air humidity less than 60%. The welding rods for welding important parts should be stored in a special insulation cylinder with a temperature of 100 ~ 150 ℃, which can be used and taken at any time.
6. When the frame is welded and assembled, the workpiece shall be firmly cushioned to prevent deformation and additional stress during welding and heat treatment.
7. Except for the cold drawn joint specified in the design of the frame, it is forbidden to use strong assembly for other welded joints, and it is not allowed to use the thermal expansion method to align the joint, so as to prevent additional stress.
8. In order to ensure the quality of frame welding, the welding site should be windproof, rainproof, snow proof, cold proof, etc.
9. For weldments requiring preheating and post weld heat treatment, the tooling equipment, temperature measuring instruments and thermal insulation protective articles for preheating and post heating shall be prepared before welding processing.
10. When welding the weld on the plane, ensure that the longitudinal weld and transverse weld (especially transverse) can shrink freely. If butt welds are welded, the welding direction should point to the free end.
11. When welding the frame, weld the welds with large shrinkage first. If there are butt welds and fillet welds on the structure, weld the butt welds with large shrinkage first.
12. When welding the frame, the transverse short weld should be welded first.
13. During the welding and processing of the frame, the welds with large stress shall be welded first to make the internal stress distribution reasonable.
14. For frame weldments with large deformation, welding stiffeners can be used reasonably according to the actual situation.
15. The combined weldment composed of multiple components shall be assembled and welded step by step, and the general combined welding processing shall be carried out after the deformation is corrected.
16. After the welding and processing of the frame, the entire internal and external surface or part of the surface of the frame shall be corrected and cleaned.
17. After welding, the surface of the frame shall be cleaned by shot blasting, which can better improve the fatigue strength of the frame.