The electrode of welding material is selected from E5015 low-hydrogen sodium type. It is dried at 380~400°C for 1.5~2h before use, and then placed in a 100°C incubator for use. Prepare the quenching tank, prepare the quenching agent, use the old iron pipe to make a trough that can be placed under the spring steel plate, and then pour the quenching agent into the quenching tank with 30% oil and 70% diesel oil. The depth is suitable for burying the steel plate.
The welding repair process is first fixed at three points on the convex surface of the spring plate, and then placed on the simple tire according to the illustration. The refractory brick is placed under the joint, and the arc-striking plate and the arc-extinguishing plate are placed at the ends of the joint. In the range of 20~30mm on both sides of the groove, preheat the plate together with the arc-extinguishing plate and the arc-extinguishing plate to 250~300°C.
Operation points (1) The welding equipment is AX-320 type electric welding machine, and the reverse welding is applied. Welding sequence short arc, linear transport method, multi-layer multi-channel.
(2) After the two layers of the concave surface are welded, the spring steel plate is turned over flatly, and when the convex root is welded, the solid welding point and the welding part clamp are cleaned by the angle machine, and the metal light is exposed without defects. (3) During the welding process, the interlayer cleaning should be carried out quickly. If the residence time is slightly longer (such as turning the spring steel plate), the weld should be reheated to 250~300 °C. (4) When welding the last layer, care should be taken to prevent undercutting, and the weld bead should be 2~4mm higher than the base metal to facilitate grinding. (5) Each layer of the weld shall be welded from the arc runner plate and extinguished by the workpiece on the arc extinguishing plate.
Welding process parameters Post-weld heat treatment 4 Normalizing treatment of normalizing process. When the weld zone is heated to 200~300 °C, borax is applied to the weld and the vicinity to prevent decarburization and oxidation of the surface of the spring plate during the treatment. Continue heating to 900~950 °C (orange), heating the total width of 80~100mm (the weld is centered), immediately wrapped with dry asbestos rope, heat preservation for 14min. Quenching treatment to remove the insulation rope, in the welding area 120~140mm range Heated to 850~900 °C (bright red), immediately wrapped with asbestos rope, after 14 minutes of heat preservation, the asbestos rope was removed, and immediately quenched in a quenching tank, quenching process.
The heating width of the tempering treatment is calculated from the center of the weld, not less than 100 mm on each side, and the heating temperature is 500-550 ° C (white-white). After 30 minutes of heat preservation, the asbestos rope is removed and cooled with water. The tempering process requires that the asbestos rope used for heat treatment must be dry, the wrapping width should be above 200mm, and the thickness should be more than 3 layers of Φ20 asbestos rope. Final treatment (1) Grinding the arc-ignition plate and the arc-extinguishing plate with a grinding wheel, and grinding both end faces to a smooth and smooth shape. (2) Grind off the weld height to the workpiece level.
Conclusion The welding of the broken spring steel plate of the crane is made by the domestic E5015 welding rod. Preheating before welding and normalizing, quenching and tempering after welding are very reliable. This process can be used for spring steel plate welding of various vehicles.
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