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Will be a problem for forging companies, usually a mold 100, the main failure mode of the mold for the wave deformation and crack turtle, and the repair technique can be extended die life savings. The mold base material is mostly 5CrNiMo, 5CrMnMo. Commonly used repair materials GHR397 and 545E, the former more. Hot forging die repair welding repair process as follows:
A weld preparation. Surfacing must first remove the turtle crack, and edge polished into rounded corners, vertical Ying Xiu 100-150 ° slope, resulting in cracks Department should crack all clear, and processed into a V-shaped groove.
2 electrodes, welding machine preparation. Diameter of 4mm GHR397 materials, selection of a DC arc welding machine or Thyristor welder welding, reverse France Welding Wire Surfacing current 190-210A, voltage 20-30V is the most suitable.
Electrode drying at 350 ° C, heat 2h, placed in 110-120 ℃ constant temperature.
Mold weld clean-up of the former defect. Cavity defects, machining, carbon arc gouging plus grinding wheel. Cavity parts of the deep, narrow wheel Clear; non-cavity parts, carbon arc gouging clean up.
4 warm-up. Surfacing before the preheating temperature of not less than 400 ° C to prevent weld crack. Motif in the process of welding temperature not less than 300 ° C, slow cooling after welding.
5 Welding Electrode. Using partitions, layered surfacing France, every weld is a weld should immediately remove welding slag and spatter, while the Hammers fast percussion weld to reduce welding stress. The first weld does not knock; the knot between the layers should be staggered. Intermittent welding re-heating is higher than the initial preheating temperature of 40-50 ° C. Transported shall Methods shipped Article swing, swing distance 2.5-3 times the diameter of the electrode.
6 after welding. After welding should be used to heat, slow cold, tempering, annealing. Slow cooling after the grinding processing.
Generally good repair, life expectancy of 90% of the new mold, repair to 1/5 2/3, shorten the production cycle, that is, to repair old, income savings expenditure.
Pressure applied to the surface of the coating of the welded core called coating. The electrode coating plays an extremely important role in the welding process. The use of a drug-free skin, light Welding Electrodes in the welding process, the oxygen and nitrogen in the air will be a substantial intrusion of molten metal, oxide and nitride formation of metallic iron and useful elements carbon, silicon, manganese and other various oxides and nitride, and left in the weld, causing the weld slag or cracks. Melt into the molten bath, the gas may cause the weld to produce a large number of pores, these factors can greatly reduce the weld mechanical properties (strength, impact value, etc.), while the weld brittle. In addition to using the optical electrode welding, the arc is very unstable, serious splash, weld forming poor.
Found in the course of practice outside in the light electrode coated with a layer from a variety of minerals composed of drug skin, make arc stability, weld quality is improved, the electrode is coated electrode. With the continuous development of industrial technology, people created a now widely used in high-quality thick coated electrode.
