The slag inclusion defect refers to the defect that dry sand, paint and other inclusions form as the molten iron enters the casting during the casting process. On the surface of the processed casting, white or black-gray inclusion spots can be seen, single or in a sheet distribution, and white is quartz sand particles. Black gray is the residue and other inclusions after hydrolytic slag, paint, foam model. This defect is commonly referred to as "sanding" or "slag inclusion", which is a very common defect in lost foam casting production. Plants that use almost lost foam casting are ubiquitous and difficult to eradicate. Only by taking various measures and carefully operating in each process can the "slag inclusion" be minimized and a satisfactory result can be obtained.
Before the lost foam castings are cooled and punched, the surface of the castings and the gating system can be judged according to the surface condition of the castings and the casting system. If the sprue cup, sprue, sprue, gate and gate surfaces or joints, and the surface of the casting are heavily sanded or cracked, there is a certain slag inclusion and sanding defects in the casting.砸 Short sprue bar or sprue lacing, you can see white spots on the fracture, and when the fracture is serious, the white spots will be formed in the fracture. Such castings are not plate-shaped, and the processed surface will have white after the pie-shaped casting machine is machined. . Black and gray spots are defective. If the process operation procedures are not strictly controlled. The castings produced have seriously affected the quality of the castings and the progress of the order completion.
Causes of slag inclusions and sand defects
After long-term observation in production practice, from the pouring cup, sprue, sprue, sprue to casting, all parts may cause sand, not the combination of casting system and casting, in the whole production During the process, the paint on the surface of the casting system is detached and cracked, the coating of the white mold joint is detached and cracked, the coating of the foam white mold is detached and cracked, and the sprue is not tightly closed, etc. main reason.
Secondly, the selection of process parameters, such as the net head size of the casting system, the casting temperature, the negative pressure, the dry sand particle size and other factors, as well as the model transportation process and the packing operation, are all very bad for the casting slag and sanding defects. Great impact. Only by adopting systematic measures and careful operation in these links can the slag inclusion defects of castings be reduced and basically eliminated, and high-quality castings can be obtained.
The above is the analysis of the reasons for the loss of mold casting slag by Qingdao Henglin Industrial Group Co., Ltd.