Quasi-circle mapping ultrasonic evaluation method for grain size of high-temperature alloy

Abstract

The invention discloses a quasi-circular mapping ultrasonic evaluation method for the grain size of a high-temperature alloy. The method comprises the following steps: sequentially carrying out ultrasonic detection and metallographic sample preparation on a reference test block, and extracting ultrasonic characteristic parameters and the grain size; normalizing the ultrasonic characteristic parameters, setting quasi-circular mapping parameters, completely projecting the normalized ultrasonic characteristic parameters to a quasi-circular space by using a quasi-circular mapping method, constructing a projection polygon, and extracting second-order ultrasonic characteristic parameters; constructing a grain size-oriented high-order polynomial fitting model, and fitting by utilizing the grain size and the second-order ultrasonic characteristic parameters; setting a fitting error as an optimization target, and optimizing by adjusting quasi-circular mapping parameters; and when the optimization target reaches the minimum, determining an optimal fitting model parameter and an optimal quasi-circular mapping parameter, and establishing a quasi-circular mapping ultrasonic evaluation model. According to the method, the second-order ultrasonic characteristic parameters are extracted through the quasi-circle mapping method, all ultrasonic information can be effectively utilized, and therefore the accuracy of the evaluation method is improved.

Description

technical field [0001] The invention relates to the technical field of measuring the grain size of a high-temperature alloy, and more specifically relates to a circle-like mapping ultrasonic evaluation method for the grain size of a high-temperature alloy. Background technique [0002] Superalloys can maintain excellent fatigue resistance, oxidation resistance, corrosion resistance and good mechanical properties in complex working environments, and are widely used in important parts such as turbine disks and casings of aero-engines, and the grain size is an important factor affecting Its mechanical properties and chemical properties are important factors, so the grain size detection of its components is an important basis for judging the quality of materials. In the actual detection process, the complex internal structure of superalloys increases the requirements for detection methods and instruments. Considering that the ultrasonic method has the characteristics of strong ...

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Problems solved by technology

Although the evaluation accuracy of this method is significantly improved compared with the traditional ultrasonic method, it is prone to problems such as high dimensionality of selected features and loss of key information in the process of selecting ultrasonic characteristic parameters using the correlation principle.

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