2017-05-15 14:59:44

Sand Casting Foundry

Ruican Sand Casting is specialized in manufacturing Sand Casting, Investment Casting, Die Casting, Green Sand Casting,Sand Casting Part,Sand Mold Casting.

Foundry sand is used for making castings, and is primarily generated by the automotive industry and its part suppliers (these deliver approximately 95 of foundry sand). It consists of clean silica sand which is of high quality or lake sand which are bonded to make molds for ferrous (iron and steel) and non-ferrous (copper, aluminum, brass) metal castings. The following types of sands are used for making molds in the foundry industry: Green Sand, Resin Coated Sand, Molasses, Cold Box Sand, Hot Box Sand, and CO2 Sand.
Sand Casting Processes in the Foundry
The two commonly used casting processes in the foundry system are as follows:
* The Sand Cast Systems --- The sand used for making sand cast moulds for ferrous castings is largely green sand which comprises of silica sand of high quality, around 10 per cent bentonite clay (which acts as the binder), up to 5 per cent water and about 5 per cent sea coal (which is an additive for improving the casting finish). This green sand forms more than 90 per cent of the molding materials utilized in the process. Various types of metals can be cast and it is the type of the metal that determines the gradation of the sand and the additives that are used in these systems.
* Chemically Bonded Sand Cast Systems --- These systems are used for 'cores' for producing cavities, which cannot be easily produced through usual molding procedures and also for molds for nonferrous castings. Here one or more organic binders are utilized along with catalysts and various setting techniques. Foundry sand constitutes around 97 per cent of this mixture.

Composition of Foundry Sand
While before being used, foundry sand is uniformly graded, the spent sand often contains
* Remnants of metal from the casting process as well as mold and core material with the binder in a partially degraded form;
* Leachable contaminants such as heavy metals and phenols which are absorbed by the sand in the course of the molding procedures (these phenols are produced by the thermal decomposition, at high temperatures, of the organic binders during the process of pouring the metal);
* And, more specifically, high concentrations of elements such as cadmium, lead, nickel, zinc and copper in brass and bronze foundries.

The green sand moulding process requires sand, clay and water to be mixed together to form a mould material that can be compacted around a pattern to produce a mould. Water develops the bonding characteristics of the clay, which binds the sand together, when used in its moist condition it is referred to as green.

When rammed and compacted around a pattern a mould of sufficient strength is produced to allow metal to be poured into it to produce a casting.

The green sand process can be used to produce castings in both aluminium and copper based metals. The process allows 90% to 95% reclamation of material and so provides a low cost form of production.

In essence we will always find the most suitable and cost effective method to casting whatever your requirement whether it be for individual light castings or multiple heavy castings.


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