Briefly describe the advantages and disadvantages and common problems of precision castings

Precision casting aluminum die-casting parts can be made into blanks with complex shapes and very complex cavities, such as casings and cylinder liners. Wide range of integration. Forging can immediately use cost-effective waste parts and drilling, and the cost of mechanical equipment is lower. The specifications and quality of castings are mostly unrestricted. The shape, specification and model of the casting are very close to the parts, thus reducing the workload of drilling and manufacturing and saving a lot of metal materials and polymer materials.

The disadvantages of precision castings are that there are various production processes, the entire production process is difficult to control, and castings are prone to defects. The uniformity of specifications and models of castings is poor, and the accuracy of specifications and models is low. Compared with stainless steel castings of the same shape and specifications, the actual quality of infrared carbon sulfur meter castings is poor, and the carrying capacity is not as good as stainless steel castings. The working environment is poor, the temperature is high, the dust is much, and the labor productivity is high.

After finishing the outer wheel gallery of aluminum die-casting, there should be no casting defects such as vent holes. Sand (slag) holes appear on the surface of the castings with uneven small gaps, which are generally irregular, with different depths and uneven interiors, without cold openings. It is important because the converter is dirty and messy, the welding bead penetrates during pouring, and the sand is shoveled when the debris is removed and delivered.

The small pebbles remaining in the metal mold are flushed into the cavity with the converter. When the mold is locked, the metal mold casting is in the middle or the metal mold casting and the sand core are extruded to cause the small stones to fall down. Metal casting sand has poor characteristics (such as low water content and poor tensile strength). Too fast water seepage during the design of the scheme can easily cause sand washing. The important reason is that the gravel in the die is not quiet. Before pouring, gravel was invaded from the enlarged opening such as sprue or sprue. The tensile strength of the sand mold is not enough, and it falls down due to external force.

Inconsistent pouring or slow pouring speed causes the gravel in the cavity to not be fully suspended on the gate, and stay in the area with lower temperature.

A layer of oxide skin caused on the outer surface of stainless steel sheet castings, also known as the black skin. It can be removed by sandblasting, of course, it can also be removed by mechanical processing and manufacturing methods. Inconvenient and quick areas can be removed by phosphating. After this layer of oxide skin, because this layer of oxide skin may fall down, the appearance will become more and more unsightly, it is not easy to choose anti-corrosion measures such as paint and electroplating. It should be said that there is not much money on the back.