After precision casting, alloy steel must undergo a series of treatments. After casting, the treatment is mainly used for the surface quality and overall shape treatment of the product. The most complex processes include shot blasting, sandblasting, acid biting, pickling, coarse grinding, and fine grinding. , Forming, welding repair, electrolytic polishing, grinding and other processes. In the processed process, the product has no fixed process, and the process is usually coordinated according to the product structure and on-site work schedule. For example, in the cleaning process, shot blasting, sand blasting and rough grinding are not coordinated according to site conditions.
For alloy steel precision casting surface quality requirements are relatively high. Perform sandblasting treatment. Blasting is powered by compressed air, and sand is sprayed onto the surface of the casting at a high speed through a spray gun to remove residual sand and scale remaining on the outer surface and inner hole of the casting. There are clear requirements for the type, thickness and burst pressure of the sand used in sandblasting. Because of pressure
If the force is too large, the surface of the product may be damaged. During the operation, care should be taken not to put the casting directly on the nozzle to prevent the casting from being sprayed. The surface of the product after sandblasting is finer than that after sandblasting.
Rough grinding is to grind the inner gate with emery cloth belt and grind it to a height less than 1mm from the surface of the casting. Then, it is finely ground. According to different surface quality requirements, fine sanding belts of different thicknesses are used for fine grinding. Care must be taken during the fine grinding process to prevent abrasion of the product surface. From the inspection workshop to the welding workshop, there are product surface defects.
Generally, the surface defects of products can be divided into two categories: convex and concave.
Prominent defects include: flashes, burrs, steel beans or more obvious mold lines.
Defects of depression are: pores, shrink pits, cuts, abrasion, etc. Grinding and repairing are the repair methods for the two main defects on the surface.
The main purpose of grinding is to use grinding tools such as pneumatic air guns and grinders, and to install different types and types of grinding heads. Flatten and smooth the prominent defects on the product surface. When repairing prominent defects on the large surface of the product, choose a sanding head, which is faster. However, steel grinding heads are used where the holes, grooves, grooves, etc. are not repaired by the grinding head. Because the steel grinding head is relatively thin, it is more convenient to repair those smaller places. Welding repair is a method of repairing dent defects, such as: air holes, shrinkage pits, cuts and wear.
The purpose of forming and welding repair of alloy steel precision casting is the same. It repairs different types of defects in different ways to make unqualified products qualified. It is mainly used to correct shape distortion products. Generally, they are easily deformed by products with simple shapes and thin walls. For those products with thick walls and complex structures, they are not easy to deform. For some foreseeable deformation, measures such as cooling tools and reasonable placement are usually used in the waxing process to prevent the deformation rate and repair rate.