Our business started in 1998 with the foundation of an aluminum reprocessing (aluminium casting) plant. We have achieved great success in our business by providing aluminum to suppliers in Europe, America and Asia. In 2002, we decided to expand our business by investing considerable capital in equipment for aluminium casting under high pressure.
Since 2003 we have been a group of companies offering superb services to our clients related to aluminium casting (aluminium casting under pressure) and CNC machining of castings.
Today SI Castings continues to be a highly successful company supplying aluminium casting products and machining services to clients throughout the European markets. Our work experience in the aluminium casting industry ranges from small to very large projects, and working within delivery schedules from the shortest time possible (3-7 days) in case of urgent need by our clients, as well as our normal large project delivery within 7-8 months.
SI Castings invests on a continuous basis in new casting equipment, and provides for advanced personnel training to improve overall efficiency, service quality and expansion of its opportunities in working with Customers.
We are certified according to the standards of the ISO 9001:2008 quality system and are ready to meet purchasers’ demands worldwide.
To start lets define what is a metal casting. Metal casting is a getting casting products (castings) by pouring molten metal into the casting mold. The working part of the casting form is a cavity in which the material hardens upon cooling, becomes a desired configuration and size of the product.
All metals without exception is available for a casting. However, not all metals have similar casting properties, particularly fluidity – ability to fill a casting mold of any shape. Casting properties depend mainly on the chemical composition and structure of the metal. Importance is the melting point. Metals with a low melting point are easy to industrial casting. Among metallic alloys a steel has the highest melting point. Metals and theirs alloys are divided into ferrous and non-ferrous. Ferrous metal alloys are a steel, malleable iron and cast iron. Non-ferrous metal alloys are other alloys that do not contain significant quantities of iron. Alloys used for metal casting, in particular, are based on a copper, nickel, aluminum, magnesium, lead and a zinc.
An aluminium casting recently used increasingly due to the lightweight and strength of the castings. These alloys have quite a high corrosion resistance, good thermal and electrical conductivity.
The tensile strength of cast aluminum alloys is in the range of from 150 to 350 MPa.
The main methods of casting are: die casting, gravity casting, centrifugal casting and vacuum casting.
A gravity casting includes a sand casting, chill casting, investment casting, lost foam casting, shell molding.
A die casting includes a high pressure die casting at casting machines with a cold chamber die (mainly aluminium casting) and low pressure die casting at casting machines with hot chamber die (as a rule, this is a zinc casting).
Great article about the aluminium casting is available here.
Casting machines are used for die casting. It fills metal (steel) casting form (which is usually called the mold and may be multicavity) with molten metal under pressure from 7 to 700 MPa. The advantages of this method are the high performance, the high surface quality, the exact dimensions of the casting product and the minimum requirement for its machining. Typical metals for this method are zinc based alloys, aluminium, copper and tin-lead. Due to the low melting temperature of them these alloys are very technologically advanced and allow for small dimensional tolerances and superior performance castings.
The complexity of the configuration in the case of this is limited so that when detaching casting product from the casting form it may be damaged. In addition, the thickness of the product is somewhat limited; more preferred articles of thin cross section, wherein the melt is rapidly and uniformly solidifies.
Casting machines for die casting there are two types of hot chamber and cold chamber die. Casting machines with hot chamber die are mainly used for zinc-based alloys. Hot chamber is immersed in the molten metal. The liquid metal is displaced from the hot chamber die into the casting mold under slight pressure of air compressed by the piston. In casting machines with cold chamber die, molten aluminum (aluminium casting), magnesium or copper alloy fills the mold under a pressure of 35 to 700 MPa.
Castings produced by aluminium casting under pressure, are used in many household appliances (vacuum cleaners, washing machines, lamps, telephones) and very widely – in the automotive industry. Casting products may be a mass of several tens of grams to 50 kg and more.
Our company uses casting machines with cold chamber for aluminium casting.
Casting molds are divided into permanent molds, expendable molds, and other molds.
Permanent molds are made of metal, graphite or refractory ceramic.
This is the most common form of permanent molds. In most cases, the mold is made of iron and is used to obtain steel ingots initially producing forged or rolled steel. Molds are “open-ended”, since the metal fills them from above by gravity. Also used are “through” molds. They are opened on top and bottom and used for continuous casting.
The aluminium castings which are got from open-ended molds casting:
Die casting molds are used with casting machines. They are sophisticated device. Theirs metal dies represent large capital costs.
Our factory uses such molds for aluminium casting.
These forms consist of two or more parts which when combined form the required cavity. The form can be vertical, horizontal or inclined surface of the connector or a deal on the individual blocks; This facilitates removal of the casting. After removing the mold can be collected and used again.
Graphite forms allow hundreds of castings, ceramics – are just a few. Graphite molds can be fabricated by machining graphite and ceramic molded easily, so that they are significantly less expensive metal molds.
Refractory mold made of china clay (kaolin), and other refractory materials. Powdered or granular refractory clay kneaded with water, the resulting mixture was molded and sintered preform mold as well as bricks or utensils.
We don’t use such types for aluminium casting.
They are of two types of material with a low melting point (gypsum) and of a material with a high melting point (based on the silica fine powder). The gypsum shell mold is made by mixing water with a gypsum binder material (polymer of the fast) to fine texture and spreading a mixture of model casting. After the mold material has hardened, it is cut, treated, and dried, and then “mated” two mold halves and pour. This method is suitable only for casting non-ferrous metals (for example for aluminium casting)
Sand molds is much less imposed any restrictions than any other. They are suitable for producing castings of any size, any shape, any of an alloy; they are the least demanding of the product design. They are made of a plastic refractory material (typically silica sand) giving it the desired configuration to filled metal being solidifying retains this configuration and is able for separating from the mold. This method can be used for aluminium casting.
This method is used for casting of precious metals, steel and other alloys with a high melting point. First, a mold is made corresponding to the cast parts. It is usually made of low-melting metal or a (machined) from brass. Then, filling the mold with paraffin, plastic or mercury (then freezing), get a model for casting. Model coated with refractory material. The material of the shell mold is prepared from a fine powder of refractory material (e.g., silica powder) and a liquid binder. Once it has hardened, the mold is heated. Paraffin or plastic model is melted and the liquid flows out of the mold. The mold is then fired to remove the gas in a heated state and pour the liquid metal, which arrives by gravity, under pressure or compressed air by centrifugal force (a centrifugal casting machine).
We don’t use such casting method for aluminium casting at our casting manufacture.
These are closed metal molds with an internal cavity corresponding to the configuration of the article and the pouring system, which are performed by machining in the cast iron, bronze, aluminum or steel block. Chill mold consists of two or more parts, after which the compound is a small hole in the lid for pouring the molten metal. To form the internal cavities chill laid plaster, sand, glass, metal or ceramic “rods”. Castings of aluminum-based alloys, copper, zinc, magnesium, tin and lead are obtained by chill casting. Especially effective is the use of this for the aluminium casting. Chill casting is used only in cases when it is required to receive at least 1,000 castings. Resource chill reaches several hundred thousand casts.