Method for reducing local defects in a casting
AssigneeQingyou Han
InventorQingyou Han
Life of this patent
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Abstract
A process of reducing internal defects or enhancing mechanical properties in local regions in a casting utilizes the combined effect of compression, high-intensity ultrasound, heat, and feeding using extra material on improving the local microstructure. A modified version of the process can be used for accelerating the creep age forming process.
Claims16
A method for reducing local defects or for improving local performance in a casting during its solidification and cooling stage in molds, the method comprising of:
- preparing an elongated sonotrode for each identified location, the sonotrode comprising a first end and a second end, the first end tightly connected to ultrasonic horn driven by an ultrasound generating system and the second end comprising a tip;
- providing casting molds with a cavity for housing the sonotrode where local defects exist;
- providing a loading device to each sonotrode in which the loading device drives the sonotrode at predetermined forces, time, and travel rates;
- placing the sonotrodes in the mold cavities with the tip of each sonotrode at a certain predetermined distance to the final surface of the casting, allowing extra material to exist between the tip of the sonotrode and the final surface of the casting;
- filling the mold cavity and the space at the front of each sonotrode with liquid metal;
- applying high-intensity ultrasonic vibrations to the liquid metal as soon as the liquid metal touches each sonotrode;
- and
- applying both ultrasonic vibration and the compressive loading to each sonotrode to push the extra material gradually into the casting at the moment when an isolated liquid pool is formed in the hot spot ahead of the sonotrode until the molds are about to open for casting ejection.
A method for reducing local defects or for strengthening local regions in a solidified casting, the method comprising of:
- identifying locations in a casting where local improvement in performance is required;
- preparing an elongated sonotrode and an anvil for each identified location, the sonotrode comprising of a first end and a second end, in which the first end tightly connects to ultrasonic horn driven by a ultrasound generating system and the second end comprises of a tip;
- preparing a loading device to each pair of sonotrode and anvil where the loading device drives the sonotrode at predetermined forces, time, and travel rates;
- placing each sonotrode and anvil pair to each location to be consolidated, with the sonotrode at one side and the anvil at the opposite side on the wall of the casting at that location;
- bringing the temperatures in the locations of the casting to predetermined temperatures;
- and
- applying ultrasonic vibration to the sonotrodes and applying the compressive loading to each pair of sonotrode and anvil to consolidate its corresponding location in the casting.
A method for accelerating the creep age forming process by enhanced local creep deformation of a metallic work piece, the method comprising of:
- preparing a plurality of an elongated sonotrode;
- providing the former or formers;
- preparing a loading device to each sonotrode;
- placing the sonotrodes to locations where accelerated creep deformation is required;
- brining the work piece to predetermined temperatures;
- and
- applying ultrasonic vibrations and loading to the sonotrodes to work on the work piece to its desired profile.
Dependencies are inferred from the claim text.