You are here: Home / Products / Coated sand

  • Coated Sand

    products banner

Resin Coated Ceramic Foundry Sand

Resin Coated Ceramic Foundry Sand is a commonly used foundry material and a method in foundry practices, it produces castings of high precise dimensions, smooth surface, free of blow holes and devoid of casting defects. It is one of the best moulding sands for cars, tractors and hydraulic parts. This method is now popularly used in core-making and moulding processes in foundry, especially as the well-known “shell method”.

Resin Coated Ceramic Foundry Sand is a dry, pre-coated sand mix that is cured by heat. Sand is coated with a phenolic novolac resin along with a hexamethylene tetramine (hexa) cross-linker and other additives specific to the core or mold making process.

The Shell Method or “Croning process” was invented by Dr. Johannes Croning in Hamburg, Germany in 1944. This process is the oldest core and mold making technology that utilizes synthetic resins. Although many additional sand core and molding making technologies have since been introduced, the Shell Sand process using resin coated sand is still a very effective core and molding process today.

Ceramic Foundry Sand was firstly introduced into foundry industry in 1999. Ceramic Foundry sand, technically as fused ceramic sand for foundry, is made from calcined bauxite which main content is aluminum oxide, processed by melting, blowing, sieving and blending. Ceramic Foundry Sand has excellent properties, including spherical shape, high refractoriness, good crush resistance, inert chemical characteristics, high reclamation yields, etc. Ceramic Foundry Sand has distinguished performance in foundry in compare with silica sand and other popularly used special sands.

Shell method molds and castings

Water jacket sand core of cylinder head made by ceramic sand RCS

Water jacket sand core of cylinder head made by Ceramic Foundry Sand RCS

Single core piece for shell method(ceramic sand RCS)

Single core piece for shell method(Ceramic Foundry Sand RCS)

Castings clutch with gating system made by shell method

Castings clutch with gating system made by shell method

The RCS using ceramic sand has more excellent advantages:

  • Higher refractoriness—-to cast metals with high pouring temperature (cast steel, alloyed cast steel, stainless steel, etc.)
  • High strength and toughness—–to produce more complicated cores with thin sections.
  • Lower thermal expansion—–to avoid expansion defects
  • Higher reclamation yields—-to reduce waste sand disposal, to decline costs.
  • Excellent flowability —–to make complicated cores.
  • Lower binder consumption—–lower gas evolution，lower manufacturing costs
  • Inert chemical characteristics—–can applied in any popular alloys，includes Manganese steel.
  • Longer storage period.

Taking advantages of Ceramic Foundry Sand, people can make high quality resin coated ceramic foundry sand, which has exceptional properties such as high refractoriness, low thermal expansion, easy to shakeout, high strength, and less gas evolution. For particularly complex cores, resin coated ceramic foundry sand has good flow-ability, which can solve the problem of being not fully formed.
The shell process of the ceramic foundry sand is of high production efficiency. The casting dimensional accuracy and the castings finish are exceptional. The used sand is easy to recycle, which greatly reduces the emission of solid wastes. The environmental benefits of this process are also remarkable.

Properties of RCS using Ceramic Foundry Sand(typical)

Resin addition,% Tensile strength,MPa Bending strength ,MPa Thermal bending strength,MPa Gas evolution, ml/g Softening point，℃ LOI,% GFN
1.9 2.8 6.3 2.5 11.3 92 1.8 AFS 58