Application prospects of low-carbon ferromanganese powder: In recent years, the domestic flux-cored wire market has shown an accelerated upward trend, with an annual growth rate of more than 60%. Domestic flux-cored wire production capacity is far from meeting the strong demand of the market, which provides a good opportunity for domestic flux-cored wire enterprises.
The welding process performance of the “metal powder type” flux cored wire in flux cored wire is similar to that of the solid wire, and the deposition efficiency and crack resistance are better than the “drug powder type”. Most of the wire powder core is a metal powder (iron powder, low-carbon ferromanganese powder and other deoxidizers), and a special arc stabilizer is added to ensure less slag, high efficiency, less spatter and stable arc during welding. In addition, the weld seam is low in hydrogen, improving crack resistance. The amount of slag produced is 1/3 of that of powdered welding wire, and it can be welded continuously in multiple layers (3-4 layers), without slag removal, which improves production efficiency. However, the bulk density of metal powders such as low-carbon ferromanganese powder filled inside the “gold powder type” flux cored wire is far from the theoretical density, and the composition adjustment of the “gold powder type” flux cored wire is heavily dependent on the metal powder. To prepare specific components had to increase the wire diameter.
Ni3al is a nickel-aluminum-based intermetallic compound, and its superdislocation has the characteristics of high deformation resistance, high work hardening rate and abnormal yield strength-temperature variation law in terms of material mechanical properties. The abnormal yield strength-temperature change law means that within a certain temperature range, the yield strength also increases with the increase of temperature. The tensile strength of Ni3al-based alloy can reach 830MPa at 727℃. It is reported that the mx246a nickel-based superalloy still has a tensile strength of 350MPa at 1100°C, and its oxidation resistance has reached a complete oxidation resistance level. Further compounding chromium carbide can further improve the high temperature wear resistance. The high-temperature wear resistance of related materials is better than that of expensive cobalt-chromium-tungsten (molybdenum) Stellite alloy, and the economy is good.
However, there are still many difficulties in preparing nickel-aluminum-based materials into welding materials. The vacuum sintering method and horizontal continuous casting method to produce nickel-aluminum-based welding wire have problems such as a long production cycle and high production cost, and cannot be put into use in batches. Using laser cladding or thermal spraying to directly use nickel-aluminum-based powder materials to prepare the cladding layer has problems such as strict particle size requirements for low-carbon ferromanganese powder, low powder forming rate, and high equipment requirements, and the production cost is still very high. . very high.
Flux-cored welding wire method to prepare nickel-aluminum-based welding materials can improve the powder utilization rate. Still, if a high proportion of nickel-aluminum powder, nickel-aluminum powder, aluminum powder and other alloy powders is required for composition control, the cost is still high. In addition, because the Ni3al material has a narrow single-phase interval in the phase diagram, its structure has a strong dependence on the composition ratio, and the composition requires a quantitative relationship of about 1:3 between the atomic equivalent of aluminum and the atomic equivalent of nickel. In preparing nickel-aluminum-based welding consumables by the flux-cored wire method, since the filled low-carbon ferromanganese powder and other metal powders are almost in a loose state, the loose density is much lower than the theoretical density. It is always impossible to prepare nickel-aluminum-based flux-cored wire with a diameter of less than 2.0mm from a metal welding skin of conventional size. However, the small wire diameter is of great significance for welding methods such as laser wire-feeding surfacing, which significantly limits the application of Ni3al-based flux-cored welding wire in laser wire feeding surfacing and other aspects.