Wuxi Dongao Nonferrous Casting Co., Ltd.
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Shrinkage Analysis Of Casting Performance On Pump Castings
- Jul 03, 2017 -

Generally, in the same carbon equivalent, the increase of silicon carbon ratio will improve the formation tendency of ferrite, but for submersible Water Pump Castings such as thin-walled small pieces, the increase in silicon carbon ratio, the formation of ferrite in the organization is not likely to affect the strength.

(1) Line contraction. The higher the formation temperature of the solid metal skeleton, the earlier the start time of the line contraction, the longer the contraction time, the greater the line shrinkage value. Under the same carbon equivalent, the increase of the silicon carbon ratio makes the number of the primary austenite, and the solid skeleton is formed earlier, thus the line contraction increases. However, in actual production, the carbon equivalent of high silicon carbon than cast iron compared with the previous process is not very different, the effect of line shrinkage is also small, in practice did not find the reason for the waste.

(2) contraction of body. Compared with high silica carbon, the traditional cast iron has lower carbon content than cast iron, but the carbon equivalent is slightly higher, so the shrinkage of this kind of cast iron has no obvious difference. This feature has also been validated in production.

(3) Sensitivity of section. High silicon carbon is less sensitive than cast iron section, which is very important to the diving Water Pump Castings which often bear the impact.

With the continuous improvement of submersible pump quality, market changes, as well as the new requirements for the use of submersible pumps, the use of traditional technology production of diving, Water Pump Castings more and more difficult to meet the requirements of casting quality. Submersible Water Pump Castings are structurally characterized as follows.

(1) The casting wall thickness difference is larger, such as impeller and diversion shell, the thinnest place only 2 3mm, the thickest place up to 25mm above.

(2) Hot section distribution, so that there is too much hardness deviation of the casting, white mouth inclination is large, poor machinability. Because of poor casting performance and difficult to control in production, we have put forward the use of high silica-carbon ratio cast iron smelting method instead of the original traditional process, after multiple furnace verification, fully meet the requirements.