Recasting defect repair method for isometric crystal cast parts

Abstract

The invention provides a recasting defect repair method for isometric crystal cast parts. The method includes the steps: adopting alloy powder with components similar to the parts and with particle size of minus 300-180 meshes, respectively adding two kinds of alloy powder, with softening temperature in gradient distribution from 10 DEG C to 50 DEG C and with particle sizes of minus 300-260 meshes and minus 300 meshes in an addition amount accounting for 4wt%-10wt% of the total amount, into the alloy powder, and adding a binding agent into the mixture to prepare a repair material A; adopting alloy powder containing tantalum and yttrium alloy elements, adding the binding agent, and mixing to prepare a pasty repair material B; during repair, coating defects with the materials A and B according to a proportion of 25wt%-30wt% prior to drying, and feeding the dried parts into a vacuum furnace for sintering so as to complete recasting repair. Repair texture which is high in mechanical strength, oxidation resistance and corrosion resistance and low in porosity can be obtained, and special diffusion treatment is not required. The method is particularly applicable to repair of big defects and high-stress areas of gas engine hot-end parts.

Description

technical field [0001] The invention relates to a method for repairing defects such as corrosion, cracks, ablation, wear, etc. of equiaxed crystal casting superalloy parts during use, especially the defect remelting and repairing of nickel-based equiaxed crystal casting superalloy parts method. Background technique [0002] Gas engine turbine rotors and stator parts, which are widely used in petroleum, electric power and aviation fields, use equiaxed crystal superalloy casting parts in large numbers because they work in high temperature and corrosive gas environment. Equiaxed crystal cast superalloys are formed and cast superalloys by ordinary precision casting methods. The organization is dominated by equiaxed crystals of different sizes, and there may be a small amount of columnar crystals locally. According to the matrix elements, superalloys are divided into iron-based, nickel-based, cobalt-based and other superalloys. At present, in advanced engines, high-temperature...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: (1) In order to ensure that the repaired tissue has a low porosity in the mixture, a large amount of demelting elements will be added to the repaired part, resulting in low mechanical properties of the repaired tissue. (2) The repair period is long, Expensive repairs requiring degreasing and prolonged diffusion in three distinct stages

The disadvantages of this method are: (1) no adhesive is added to the equivalent material and solder, which makes it difficult to maintain the equivalent material and solder at the crack; (2) in order to ensure that the repair tissue has a lower Porosity, the mixed method of equivalent material and solder used, will add a large amount of demelting elements to the repaired part, which will lead to lower mechanical properties of the repaired tissue

The disadvantage of this method is that the proportion of alloy powder and brazing material is 50wt%, and the demelting elements such as boron, silicon, phosphorus in the repaired tissue are relatively high, and the skeleton-like pores formed between the alloy powders easily lead to the failure of the repaired tissue. lower mechanical properties

Therefore, for some large-area high-temperature alloy casting parts with damage, burns, material loss, and areas that require high mechanical properties, the repair tissue is difficult to meet the use requirements, and it requires a long time of diffusion treatment, which will increase The thermal damage of the machine parts prolongs the repair period of the machine parts and increases the repair cost