Suggestions and Measures for Deformation of Hydraulic Castings


Release time:

2023-03-06

In the manufacturing process of precision hydraulic castings, due to some problems in hardware facilities, management, pouring cooling, correction, etc., casting deformation will occur. What should I do if I encounter hydraulic casting deformation?

Suggestions and Measures for Deformation of Hydraulic Castings

In the manufacturing process of precision hydraulic castings, due to some problems in hardware facilities, management, pouring cooling, correction, etc., casting deformation will occur. What should I do if I encounter hydraulic casting deformation?

Hydraulic casting deformation can be divided into micro self-deformation, flaring deformation and warping deformation.

Microscopic self-deformation: In alloy materials, gray cast iron is prone to microscopic self-deformation. The residual stress after sand cleaning of gray cast iron is mainly residual thermal stress. Residual stress is not only the cause of cold cracking and deformation of castings, but also the main cause of slight self-deformation. Even if the residual stress does not exceed the yield strength of the material, gray cast iron will slowly undergo microplastic deformation with time under its action, this is called micro-self deformation.

Flaring deformation: the reason is that the sand core or sand mold with opening size prevents the casting from shrinking, resulting in plastic deformation of the free structure of the hydraulic casting opening, resulting in flaring deformation defects.

Warping deformation: after sand mold cleaning, both ends or even one end of the casting appear warping deformation, which makes the middle of the casting sag, resulting in uneven casting. This form of deformation is called warping deformation. The reasons are as follows: when the casting is cooled, the thickness or thickness of the casting is uneven, and there is a temperature difference, resulting in different cooling speeds in various parts of the casting, resulting in uneven plastic deformation and warping.

液压铸件

In view of the deformation of precision castings, this paper mainly puts forward four suggestions and measures:

1. Before wax injection, find out the preset mold in the wax injection chamber and start wax injection until the mold temperature is the same as the room temperature in the wax injection chamber. As for the temperature of the wax parts when making the shell later, there is no need to mention it, because there is no good control there, it may be directly listed, and the shell will expand.

2. After the wax sheet comes out, the first thing to do is self-inspection, mainly to check whether the demoulding project has deformation or other defects; wax pieces should be placed neatly and evenly, and overlap and suspension should be avoided as much as possible; it is recommended to use fixture inspection as much as possible to improve the detection speed and accuracy, and calibrate the fixture according to a certain period.

3. When the temperature of the module is still high after the furnace is turned on, overlap should be avoided and placed regularly to make the deformation direction consistent so as to shape and correct the fashion clip.

4. The fixture of the correction liquid die casting should be made of hard material, and the surface should be wear-resistant. For some parts with large area, the tonnage of the press or punch should be calculated reasonably to avoid equipment waste or insufficient strength.

Precision hydraulic castings have a great influence on the performance of mechanical products. Poor quality precision castings will seriously affect the service life of mechanical products. Therefore, once investment casting deformation is found, it should be corrected in time to avoid the impact of investment casting on the performance of mechanical products.