How to avoid carburizing of hydraulic castings?


Release time:

2023-02-22

The basic components of hydraulic casting coating include refractory material, carrier, binder, suspending agent, surfactant, defoaming agent, etc. Refractory material is the skeleton of coating, and its heat resistance, strength and air permeability are recognized, thus avoiding defects such as sand sticking and burrs and obtaining smooth appearance. Refractory material is generally ceramic powder, and the selection of type depends on the type of pouring metal, pouring temperature, part thickness, sand performance, etc, in order to achieve good results, you can mix different particle sizes of the same refractory powder, or mix several different particle shapes and sizes of ceramic powder, hydraulic castings in the production process, due

How to avoid carburizing of hydraulic castings?

Today, Xiaobian and we talk about how to avoid hydraulic casting carburizing.

The basic components of hydraulic casting coating include refractory material, carrier, binder, suspending agent, surfactant, defoaming agent, etc. Refractory material is the skeleton of coating, and its heat resistance, strength and air permeability are recognized, thus avoiding defects such as sand sticking and burrs and obtaining smooth appearance. Refractory material is generally ceramic powder, and the selection of type depends on the type of pouring metal, pouring temperature, part thickness, sand performance, etc, in order to achieve good results, powders of the same refractory materials with different particle sizes can be mixed, or ceramic powders with several different particle shapes and sizes can be mixed. During the production and processing of hydraulic castings, carburizing will occur due to its own or operational reasons. The appearance of carburizing will make the castings not tight enough and affect the use function, so we need to do preventive work in time, and then admit that the production process of hydraulic castings will not be affected.

液压铸件

Here we teach you how to avoid this phenomenon

1. Taking advantage of the characteristic that the farther away from the inner gate, the more serious the carburization is, the riser is set at the far end away from the inner gate or the high point of the casting, so that the molten steel with serious carburization pollution entering the casting enters the riser, and together with the riser, it also plays the role of collecting slag and gas. With this process, the total carbon content of the casting can be controlled within the process requirements. The function of the coating is as follows, identify the appearance quality of the casting; improve the strength of the foam so that it will not deform during handling; so that the gas generated during the pouring process is discharged and pumped through the coating.

2. Choosing foam materials with less carbon content is the key. At present, there are three main casting materials: EPS, STMMA and EPMA, whose carbon content decreases in turn. Among them, STMMA has the advantages of less gas generation and low carbon content, and is an important material for lost foam casting production.

3. The density of hydraulic castings is particularly important. As long as the appearance is bright and the density is low, carburizing can be reduced, gas generation is less, casting simplifies core making and sand treatment processes, the processing capacity between processes is small, labor intensity is significantly reduced, mechanization and automatic production are simple, because no core is required, the precision of castings is completed together, the workload of finishing is reduced, and the noise and dust in the workshop are also reduced accordingly.

Commonly used hydraulic castings include silica, alumina, zircon, chromite, aluminum silicate, etc. A carrier is needed to adjust the viscosity of the coating, and the refractory material is coated with a foam model of the corresponding thickness. Generally speaking, the coating of the casting is Water, rarely alcohol, other solvents that may react with the foam model cannot be used. The adhesive binds the components in the paint together, and admits that the paint is bonded to the outside of the foam model during painting, the adhesive is mostly one or several adhesives. The adhesive not only admits that the paint adheres to the surface of the foam model before drying, but also provides the corresponding strength after the paint is dried and poured. The main function of the suspending agent is to The carrier forms a colloid, and then suspends the refractory ceramic powder to identify the fluidity of the coating and avoid the mobilization and precipitation of solid particles.