1. The necessity of die-casting mold welding
The service life of a die-casting mold depends on the material quality and manufacturing process. However, in the process of long-term use, it will cause damage, cracks, deformation, and other problems due to the influence of gas, moisture, oil, and other factors. At this time, welding modern technology can solve these problems well. Therefore, proper maintenance and repair can greatly extend the service life of the mold before it expires.
2. Welding material selection
Common die-casting mold welding materials are nickel-chromium alloy, cobalt-based cemented carbide, stainless steel, etc. When selecting, it is necessary to select the corresponding welding material according to the composition of the mold material and the conditions of use. For example, if the mold material is H13, nickel-chromium alloy can be used as the welding material.
3. Welding pretreatment
Before welding, the mold should be cleaned to remove grease, dust, and other debris in the welding area. Cracks or defects on the mold surface need to be treated. In the absence of hydrogen embrittlement, magnetic particle detection or crack detection methods can be used to determine whether there are cracks in the welded area and their length, depth, and other parameters.
The purpose of preheating is to reduce the deformation of the heating area of the mold and reduce the temperature difference during welding. The common preheating temperature is 150°C-200°C, and the minimum preheating should be 2 hours.
5. Welding process
Common welding processes include TIG welding, MIG welding, arc welding, etc. Under the conditions of suitable welding materials and processes, the welding materials are heated to a molten state, filled in the damaged parts of the mold, and the repair parts with the same properties as the mold materials can be obtained after cooling.
6. Post-welding treatment
Post-welding treatment is mainly exothermic treatment of the welding hot area, which is slowly cooled (cannot be quenched immediately). After welding, it is necessary to remove undesirable defects such as welding tumors and trachoma, and carry out processing, grinding and other treatments.
Good welding material and welding process selection, suitable pretreatment, preheating, welding process, and post-welding treatment can avoid the occurrence of mold welding phenomenon, and can greatly extend the service life of the mold.