Castings and methods for evaluating hot cracking propensity during investment casting of superalloys

Abstract

The invention provides a casting and method for evaluating the hot crack tendency of the high temperature alloy investment casting process. The investment casting adopts a step test model with an extra large variable-section coefficient; the model comprises a cylinder, the bottom of the cylinder is connected with four pairs of thin plates of different thickness, the top center of the cylinder is connected to the bottom of a sprue, and the top of the sprue is connected with a truncated cone-shaped pouring gate. After adopting the casting and method, the hot crack tendency condition of the high temperature alloy investment casting under the conventional casting processing conditions is found out, the improvement of the casting technology is guided, reasonable advice can be supplied for the structural design of the casting, so that the hot-crack forming tendency of the high temperature alloy investment casting is expected to be reduced from the source, and the other existing hot crack evaluation methods cannot be compared with the advantages.

Description

technical field [0001] The invention relates to the field of nickel-based superalloy investment casting, in particular to a casting used for evaluating the thermal cracking tendency of a high-temperature alloy investment casting process, and using the casting for the thermal cracking tendency of a nickel-based superalloy method of evaluation. Background technique [0002] A large number of high-temperature alloy castings are used in the hot end parts of aero-engines and gas turbines, and the new generation of aero-engines is very strict in structural design. The investment castings often have a huge difference in wall thickness, and hot cracking is very easy to occur during the investment casting process. , reduce the yield of castings. [0003] Found through literature search to prior art: [0004] The Chinese invention patent with the application number 201210265562.X relates to a method for evaluating the thermal cracking tendency of directionally solidified columnar su...

AI Technical Summary

Problems solved by technology

According to the thin-wall characteristics of directionally solidified blades, this patent establishes a thin-walled tubular directional solidified sample device, which better evaluates the thermal cracking tendency of directionally solidified columnar superalloys. cross-section problem, and cannot be applied to the evaluation of hot cracking tendency of equiaxed crystal castings

However, this patent can only evaluate the thermal cracking tendency of the material itself, without considering the influence of the actual casting structure on the casting hot cracking tendency

[0006] The Chinese invention patent with the application number 201310029899.5 relates to the method of crack sensitivity testing of precision steel castings and its test model. The patent uses a grid model, with different fillet sizes at grid transitions and different thicknesses of grid ribs. , which has the advantage of being able to effectively predict the tendency of cracks in different materials and process parameters during the investment casting process, but the design of this patent is too complicated, and the interaction between the grids is serious, which reduces the accuracy of the evaluation results of hot cracking tendency

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