If you want to know why the results of machine tool casting repair are not ideal, you can find out the reasons by analyzing several kinds of traditional welding repair techniques at the defects of machine tool castings. Through the research on the repair results of the casting defect repair machine in the machine tool casting, a new technology and process can be determined. It is indeed feasible to repair the machine tool casting.
The welding repair results of the traditional welding repair process and the analysis material HT200, the area of ​​the guide rail defect S<1000mm2, depth h<8mm. Heat treatment conditions: 3 were not surface-quenched and 1 had been surface-quenched. Used nickel-based welding powder F103, cast iron electrode for arc welding: Z308, Z248. 2.1.2 spray welding equipment, arc welding equipment, nickel-based welding powder F103 (C ≤ 0.158.0
1. Spray welding is performed according to the spray welding process. Preheat the guide rail surface to 150°C or more. After the preliminary solder powder is sprayed, heat the coating surface to 900°C-1200°C or more to form a flat surface after melting the solder powder. Due to the long preheating and heating time, the workpiece has a large heated area and a large thermal stress. It is more prone to cracks than arc welding. At the same time, the line shrinkage tends to produce more cracks. Because the crack tends to be influenced by the spray welding time, the thickness of the sprayed layer and other factors, the size of the defect is limited, and the defects of the welding repair must be cleaned. Because of the high proportion of Fe contained in the powder spray, the spray layer formed is better than the arc welding and the mother. The color of the wood is more similar. However, due to the presence of a certain amount of Ni, it is not possible to get closer to the base metal, and it can be machined after welding.
2. Arc welding with welding rod Z248 for welding, welding repair process is divided into two kinds, the first kind: preheating before welding to 550 °C -650 °C, 5-8 hours after welding insulation; second: before welding workpiece Do not preheat, keep 3-4 hours after welding. Both methods are prone to cracks, hard spots, and are not easily machined after welding. Welding rods are cheap. Welding with nickel-based cast iron electrode Z308, the gap between the welding layer and the welding layer should be cooled to below 60°C, less porosity, cracks in the welding area, good machinability, high bonding strength, no shedding phenomenon, due to the machine guide After the processing, the influence of the oil absorption and the welding rod's blowing force is easy to produce undercuts and the formation of "welding traces". The color of the welding repair zone is very different from that of the base metal, and the welding rod is expensive.
3, from the analysis results can be drawn:
The traditional welding repair process can not completely solve the root cause of machine tool rail defect repair is the unified spray welding, arc welding process, easy to produce cracks after welding repair, the workpiece is susceptible to thermal deformation, prone to secondary air holes, weld metal color and the base metal Big differences are their common features.
The welding repair results of the traditional welding repair process and the analysis material HT200, the area of ​​the guide rail defect S<1000mm2, depth h<8mm. Heat treatment conditions: 3 were not surface-quenched and 1 had been surface-quenched. Used nickel-based welding powder F103, cast iron electrode for arc welding: Z308, Z248. 2.1.2 spray welding equipment, arc welding equipment, nickel-based welding powder F103 (C ≤ 0.158.0
1. Spray welding is performed according to the spray welding process. Preheat the guide rail surface to 150°C or more. After the preliminary solder powder is sprayed, heat the coating surface to 900°C-1200°C or more to form a flat surface after melting the solder powder. Due to the long preheating and heating time, the workpiece has a large heated area and a large thermal stress. It is more prone to cracks than arc welding. At the same time, the line shrinkage tends to produce more cracks. Because the crack tends to be influenced by the spray welding time, the thickness of the sprayed layer and other factors, the size of the defect is limited, and the defects of the welding repair must be cleaned. Because of the high proportion of Fe contained in the powder spray, the spray layer formed is better than the arc welding and the mother. The color of the wood is more similar. However, due to the presence of a certain amount of Ni, it is not possible to get closer to the base metal, and it can be machined after welding.
2. Arc welding with welding rod Z248 for welding, welding repair process is divided into two kinds, the first kind: preheating before welding to 550 °C -650 °C, 5-8 hours after welding insulation; second: before welding workpiece Do not preheat, keep 3-4 hours after welding. Both methods are prone to cracks, hard spots, and are not easily machined after welding. Welding rods are cheap. Welding with nickel-based cast iron electrode Z308, the gap between the welding layer and the welding layer should be cooled to below 60°C, less porosity, cracks in the welding area, good machinability, high bonding strength, no shedding phenomenon, due to the machine guide After the processing, the influence of the oil absorption and the welding rod's blowing force is easy to produce undercuts and the formation of "welding traces". The color of the welding repair zone is very different from that of the base metal, and the welding rod is expensive.
3, from the analysis results can be drawn:
The traditional welding repair process can not completely solve the root cause of machine tool rail defect repair is the unified spray welding, arc welding process, easy to produce cracks after welding repair, the workpiece is susceptible to thermal deformation, prone to secondary air holes, weld metal color and the base metal Big differences are their common features.
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