A kind of hot and cold twin-wire nickel-based alloy submerged arc surfacing sintering flux and preparation method thereof

Abstract

The invention discloses a cold and hot double-wire nickel-based alloy submerged arc surfacing sintering flux and a preparation method thereof. The flux is prepared from solder and high modulus potassium silicate water glass binder, wherein the solder is made of Al 2 O 3 , TiO 2 , CaF 2 , K 3 AlF 6 , Cr 2 O 3 , potassium sodium titanate, molybdenum powder, nickel powder, niobium powder mixed and sintered. The component formula of the invention is used for the modified surfacing welding of the special-shaped surface of the membrane water-cooled wall of the power station boiler. Arc radiation; through the special electrode arrangement with the cold wire in the front and the hot wire behind and the adjustment of the welding angle of the hot wire, it can effectively reduce the penetration depth, reduce the dilution rate of the surfacing layer, and significantly improve the deposition efficiency. It ensures the effective transition of various metal elements in the nickel-based welding wire, obtains a nickel-based alloy surfacing layer with stable and uniform composition, and achieves excellent resistance to high temperature flue gas wear and hydrogen sulfide corrosion.

Description

technical field [0001] The invention relates to the technical field of metal surface surfacing repair and modified high-efficiency surfacing welding, especially the flux used in the nickel-based alloy submerged arc automatic surfacing process on the surface of ordinary carbon structural steel, in particular to a cold and hot double-wire nickel-based Alloy submerged arc surfacing sintering flux and preparation method thereof. Background technique [0002] Corrosion of waste heat boilers in power plants is a common problem, especially the corrosion of the first channel is very serious. During the operation of the boiler, the furnace temperature can be as high as 1600°C. Due to the presence of sulfur and other harmful impurities in the combustion coal, the water wall is not only generally subjected to high-temperature flue gas and high-speed erosion of ash particles, but also accompanied by the SO produced during the combustion process. 2 , SO 3 、H 2 Harmful substances such ...

AI Technical Summary

Problems solved by technology

The direct harm of water wall corrosion is mainly manifested in the following two aspects: one is to make the pipe wall thinner. According to statistics, the annual thinning amount is generally about 1mm, and the serious one can even reach 5-6mm years, forming a serious hidden danger to safe operation , increasing the workload of temporary maintenance and overhaul of the power plant, causing great economic losses to the power plant

Second, a sudden pipe burst accident occurred in the water-cooled wall, resulting in an emergency shutdown of the furnace for emergency repairs, which not only disrupted the normal power generation order of the power plant, reduced the output value of power generation, but also increased the labor intensity of workers and additional maintenance costs, directly affecting the company's profitability. It also interferes with the normal dispatch of the regional power grid and affects local industrial and agricultural production, which also caused a great social impact

The existing surfacing welding method basically adopts molten inert gas shielded welding (MIG) welding, which has the advantages of high degree of automation, is conducive to observing the state of the molten pool and the formation of the weld seam, and easy to adjust welding parameters; There are still many disadvantages in the surfacing welding of the conventional water-cooled wall, and the MIG welding method also has many disadvantages: the first is that the diameter of the welding wire is small, and the surfacing efficiency is low. Second, the surfacing layer metal can reach the design composition of the surfacing welding wire under the joint action of base metal melting dilution and welding burn loss, and the composition of the surfacing layer is uneven; third, there is spatter in the welding process, and the appearance quality of the weld Poor, the utilization rate of welding materials is low, even if a special welding power source is used to control the transfer of welding droplets, it can only reduce the splashing of droplets to a certain extent

[0006] The heat input of submerged arc welding is high, the depth of penetration is large, the metal dilution rate of the surfacing layer is large, and the welding deformation is also large; the alloy content is high, and the welding pool is prone to produce more intermediate phases, resulting in sticky slag in the weld and difficult slag removal; at the same time , the heat generated by welding is easy to burn the alloy elements, reduce the mechanical properties of the surfacing layer and deteriorate the corrosion resistance, especially the poor intergranular corrosion resistance; when it is applied to thin-walled pipe fittings for small current and high-speed welding, it is difficult to ensure the integrity of the welding arc Stability, resulting in poor weld appearance

Images