Method for controlling quality of castings obtained through low pressure casting and dynamic pressure detecting device thereof

A technology of low-pressure casting and detection device, applied in the direction of measuring device, measuring fluid pressure, instrument, etc., can solve the problems of increasing production cost, wasting metal liquid, increasing energy consumption, etc., and achieving the effect of reducing production cost and saving metal

Inactive Publication Date: 2012-07-11
NANTONG L S LIGHT METAL FORMING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] In low-pressure casting production, due to the failure of production equipment and the fluctuation of moisture in the mold, during the process of rising and filling the liquid metal, the liquid metal often cannot enter the cavity of the mold smoothly according to the designed process, resulting in low pressure Castings are scrapped due to casting defects
[0003] However, due to the production conditions of low-pressure casting and the limitation of the metal in the molten state, it is impossible to directly observe the rising filling and solidification process of the metal liquid in the mold cavity.
Therefore, due to the influence of unfavorable factors in the production process, the waste products that may lead to the scrapping of castings can only be discovered at the end of production, which wastes a lot of metal liquid, increases energy consumption, and leads to an increase in production costs.

Method used

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  • Method for controlling quality of castings obtained through low pressure casting and dynamic pressure detecting device thereof
  • Method for controlling quality of castings obtained through low pressure casting and dynamic pressure detecting device thereof
  • Method for controlling quality of castings obtained through low pressure casting and dynamic pressure detecting device thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Embodiment 1 Take the SF6 switchgear shell as an example:

[0028] The shape of this product is a straight cylinder plus two side flanges, the diameter is Φ550mm, the shell height is 1015mm, the wall thickness δ is 26-34mm, and the pressure to be borne during work is 580KPa. Its low-pressure casting process setting parameters are filling pressure 0-100KPa, filling time is 40s, holding pressure is 100KPa, holding time is 20 minutes, and the pressure is controlled at 100 (1±0.5%) KPa during the pouring process According to statistics, from January 1, 2010 to the present, a total of 1,500 pieces of casting products were cast, and 37 pieces were scrapped due to casting defects, with a pass rate of 97.53%.

Embodiment 2

[0029] Embodiment 2 takes the circuit breaker housing as an example:

[0030] This product has a slender main pipe with two branch pipes, the wall thickness is very thin, the diameter of the main pipe is Φ300mm, the diameter of the branch pipe is Φ253mm, the length of the shell is 1807mm, and the wall thickness δ of the branch pipe and the main pipe is only 9-10mm. It is 650KPa. Since the wall thickness is relatively thin, it requires high casting quality to bear the pressure. Its low-pressure casting process setting parameters are filling pressure 0-100KPa, filling time is 45s, holding pressure is 100KPa, holding time is 18 minutes, and the pressure is controlled at 100 (1±1%) KPa during the pouring process According to statistics, from January 1, 2010 to the present, a total of 2,025 pieces of casting products were cast, and 166 pieces were scrapped due to casting defects, with a pass rate of 91.8%.

Embodiment 3

[0031] Embodiment 3 is used for 220KV combined switchgear housing as an example:

[0032] This product has a complex shape, one of the planes has 3 side-by-side flanges, the solidification sequence during casting is not easy to grasp, and casting defects such as pinholes are prone to appear on the flange sealing surface. The diameter of the flange is Φ544mm×3, and the length of the shell is 1665mm, the wall thickness δ is 30mm, and the pressure to be borne during work is 680KPa. Its low-pressure casting process setting parameters are filling pressure 0-100KPa, filling time is 64s, holding pressure is 100KPa, holding time is 25 minutes, and the pressure is controlled at 100 (1±2%) KPa during the pouring process According to statistics, from January 1, 2010 to the present, a total of 324 pieces of casting products were cast, and 39 pieces were scrapped due to casting defects, with a pass rate of 87.96%.

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Abstract

The invention relates to a method for controlling the quality of castings obtained through low pressure casting and a dynamic pressure detecting device thereof. During mold filling, a pressure chamber of a low pressure casting holding furnace is inflated according to the requirements of low pressure casting, so as to input pressure to the pressure chamber, and the real time pressure of the pressure chamber is P0; during the mold filling process, real time pressure P1 of the pressure chamber of the low pressure casting holding furnace is read in a real time manner by utilizing the dynamic pressure detecting device; the real time pressure P1 is compared with the real time pressure P0; if the real time pressure P1 is within a pressure fluctuation range, mold filling is continuously conducted; and if the real time pressure P1 is beyond the pressure fluctuation range, mold filling is immediately stopped. By using the dynamic pressure detecting method provided by the invention, abnormal changes of the pressure in the pressure chamber under production anomaly circumstances can be timely measured, whether the metal liquid mold filling state is abnormal or not in the low pressure casting production process can be judged, the production process can be timely interrupted, and whether problems exist in the sealing performance, the moisture of molding sand and the breathability of the molding sand are detected by taking measures. Metal is saved, the production cost is reduced, and the method and the dynamic pressure detecting device thereof are particularly suitable for the production of large-scale low pressure castings.

Description

technical field [0001] The invention relates to a method for controlling the quality of low-pressure casting castings, and also relates to a dynamic pressure detection device used in the method for controlling the quality of low-pressure casting castings. Background technique [0002] In low-pressure casting production, due to the failure of production equipment and the fluctuation of moisture in the mold, during the process of rising and filling the liquid metal, the liquid metal often cannot enter the cavity of the mold smoothly according to the designed process, resulting in low pressure Castings are scrapped due to casting defects. [0003] However, due to the production conditions of low-pressure casting and the metal limitation of the molten state, it is impossible to directly observe the rising filling and solidification process of the metal liquid in the mold cavity. Therefore, due to the influence of unfavorable factors in the production process, the waste products...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D18/04G01L11/00
Inventor 翟春江周素洪翟春泉屈汉平王进许丽英
Owner NANTONG L S LIGHT METAL FORMING
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