Brief description of valve casting process
Today, let’s learn about the valve casting process with you,The casting of the valve body is an important part of the valve manufacturing process. The quality of the valve casting often directly determines the quality of the valve, and they are closely related.
Sand casting: Sand casting commonly used in the valve industry can also be divided into various types of sand such as wet sand, dry sand, and water glass sand according to the different binders.
(1) Green sand is a molding process method in which bentonite is used as the binder in the work. Its characteristics are: the sand mold does not need to be dried or undergoes special hardening treatment, the sand mold has a certain wet strength, and the sand core and shell have good concessions, which is convenient for casting cleaning and sand falling. The molding production efficiency is high, the production cycle is short, and the material cost is also low, which is convenient for organizing assembly line production. Its disadvantages are: castings are prone to defects such as pores, sand inclusion, and sticky sand, and the quality of castings, especially the internal quality, is far from enough.
(2) Dry molding sand is a modeling process with clay as a binder, and a little bentonite can improve its wet strength. Its characteristics are: the sand mold needs to be dried, it has good air permeability and air dispersion, and it is not easy to produce defects such as sand washing, sticking sand, and pores, and the inherent quality of the casting is also relatively good. Its disadvantages are: sand drying equipment is required, and the production cycle is relatively long.
(3) Water glass sand is a molding process method with water glass as a binder. Its characteristics are: water glass has the function of being able to harden automatically when it encounters CO2, and can have various advantages and disadvantages of gas hardening modeling and core making. However, there are disadvantages such as poor shell collapsibility, difficulty in sand cleaning for castings, and low recycling rate of used sand.
Resin self-hardening sand is preferably made by continuous sand mixer, which is formed by adding raw sand, resin, curing agent, etc. in turn, and mixing them quickly. It can be mixed and used at any time. The order of adding various raw materials when mixing resin sand is as follows: original sand + curing agent (p-toluenesulfonic acid aqueous solution) – (120-180S) – resin + silane – (60-90S) – sand (5) Typical sand type Casting production process: precision casting.
All of the above are shared with you todayBrief introduction of valve casting process, mainly to share with you that there are three different ways of sand casting according to the binder: wet sand, dry sand, water glass sand.