Casting Surface Roughness

In this paper, the influence of grain size of base sand . AFS grain fineness number -. molding process*, coating, melting metal flowing process and blast-cleaning to found surface are summarized, the character of abrasive are analysed. There are a lot of experiment and analysis about abrasive granularity, speed, blasting quantity to surface roughness and efficiency. The relation of surface roughness and coating are tested and analysed too. It indicates that the bigger of abrasive granularity and the higher of projection speed , the higher of roughness. The more of the abrasive, the higher of the efficiency. Gradation abrasive has a higher efficiency than the same size abrasive and has lower roughness of surface.In this paper, the influence factor about foundry surface roughness are summarized such as molding process, grain size of base sand, AFS grain fineness number, coating, melting metal flowing process and abrasive blast-cleaning at casting. The character of steel abrasive is detailed analysed. The connection about abrasive blast-cleaning' technics parameter and roughness is found by experimentation and analysed. The intention is looking for the throw speed, steel abrasive's granularity and the best abrasive for production.Although there are many infection factor about foundry roughness, the abrasive blasting-cleaning is the most important to foundry roughness. Abrasive blasting-cleaning can transform the originality roughness of foundry. By choiceing a kind steel abrasive granularity, throwing speed and cleaning technics, it can get hold of a good roughness but lower cost.In laboratory, we study the character of abrasive such as size, rigidity, density, microstructure and life at first. And studied the chemistry component by using chemistry' analytical method, the size by using disparting, the density by using replacement of alcohol, the life by using Irving examination equipment, the rigidity and microstructure. The result indicates that the abrasive making by centrifugal pouring is better than the abrasive making by atomization pour in shell, but too much in air hole and crack in it. The life of centrifugal pouring abrasive is about 2200-2400 revolutions per 100g expend and 2700 revolutions per lOOg to atomization pour abrasive which has density 7. 4g/cm3.In Shanghai Murga Steel Abrasive Co.,Ltd, we studied the influence about size, speed and throwing quantity to roughness and efficiency by using USF Wheelabrator Allevardcoming from USA. The size include S390 S460, S550 and S550 gradation abrasive to the speed include 50m/s 60m/s 70m/s. 80m/s are all studied. It indicates that the bigger of the size, the higher of the roughness, and the higher of the speed ,the higher of the roughness, and the much throwing grain, the higher clearing efficiency. It can gained higher clearing efficiency and better surface by using gradation abrasive than singleness size abrasive.It also studied the connection of surface roughness to coating by using some equipments. The result indicates that surface roughness has importance influence to coating. For example, the casting which has Ra=9.8um roughness can be able to bear cauterization for 44 hour, and the casting which has Ra=11.2um roughness can be able to bear cauterization for 22 hour only. If there are higher surface roughness there are no infection to coating accrete face almost.Bases on the experiment result, we choose a kind of abrasive for production which has higher quality. The S460 gradation abrasive can produce lower roughness casting such as Citroen and 491 engine cylinder using +GF+ rat-cage wheelabrator. In order to obtain proper surface roughness and higher clearing efficiency, we analysed and studied the equipment and technics parameter. In production the infection factor to clearing efficiency are abrasive size, throwing hotspot, throwing quantity, adding mode, throwing speed and separator adjusting, etc. The matter of casting clearing is dividing dust from casting and come out originality surface. Although it can change surface roughness by long time clearing,...