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CategoriesGrey Iron Lost Foam Casting
BrandOBT casting part Manufacturer
MaterialGray Cast Iron, HT200, HT250, GG20, GG25
Manufacturing ProcessLost Foam Casting + CNC Machining
ApplicationGear Box Cover for Heavy Duty Trucks
Heat TreatmentAnnealing + Nomorlization
Update TimeMarch 23,2023
Detail Information

China OEM custom lost foam casting products of gray cast iron according to your drawings and requirements (chemical composition of the material, required mechanical properties, tolerances, heat treatment and surface treatment), used for heavy duty truck gear box cover. 

Lost Foam Casting, also called Lost Foam Casting (LFC) or Full Mold Casting, is a kind of Evaporative Pattern Casting (EPC) with dry sand casting process. The EPC is sometimes could be short for Expendable Pattern Casting because the lost foam patterns could be used only once. After the foam patterns are finished by special machined, then the foamed plastic patterns are coated with refractory coating to form a strong shell to withstand the molten metal. The foam patterns with shells are put into the sand box, and fill it with dry sand sand around them. During pouring, the high-temperature molten metal makes the foam pattern pyrolyzed and “disappears” and occupies the exit cavity of the patterns, and finally the finished desired castings are obtained.

Lost Foam Casting vs Vacuum Casting
ItemLost Foam CastingVacuum Casting
Suitable CastingsSmall and medium-sized castings with complex cavities, such as engine block, engine coverMedium and large castings with few or no cavities, such as cast iron counterweights, cast steel axle housings
Patterns and PlatesFoam patterns made by moldingsTemplate with suction box
Sand BoxBottom or five sides exhaustFour sides exhaust or with exhaust pipe
Plastic FilmThe top cover is sealed by plastic filmsAll sides of both halves of sand box are sealed by plastic films
Coating MaterialsWater-based paint with thick coatingAlcohol-based paint with thin coating
Molding SandCoarse dry sandFine dry sand
Vibration Molding3 D VibrationVertical or Horizontal Vibration
PouringNegative PouringNegative Pouring
Sand ProcessRelieve negative pressure, turn over the box to drop sand, and the sand is then reusedRelieve negative pressure, then the dry sand falls into the screen, and the sand is recycled

Cast iron is an iron-carbon cast alloy with other elements that is made by remelting pig iron, scrap, and other additions. For differentia- tion from steel and cast steel, cast iron is defined as a cast alloy with a carbon content (min 2.03%) that ensures the solidification of the final phase with a eutectic transformation. Depending on chemical specifications, cast irons can be non- alloyed or alloyed. The range of alloyed irons is much wider, and they contain either higher amounts of common components, such as silicon and manganese, or special additions, such as nickel, chromium, aluminum, molybdenum, tungsten, copper, vana- dium, titanium, plus others. Generally speaking, the cast iron could be divided into gray iron, ducitle iron (nodular iron), white cast iron, compacted graphite iron and malleable cast iron. 

lost foam casting process at RMC Foundry in China

The Steps of Lost Foam Casting:
1- Use foam molds to produce foam patterns and casting gating systems
2- Bond the patterns and runners to form a mold bundle module
3- Dip paint on the module
4- Dry the paint
5- Put the module into the sand box and fill it with dry sand
6- Vibrate molding in order to fill the cavity with dry sand and then compact the molding sand
7- Pouring molten metal to vaporize the foam and then forming the desired castings
8- After the castings have cooled, clean the castings. The dry sand can be recycled

Advantages of Lost Foam Casting:
✔ Greater design freedom for complex structural castings
✔ No draft angle is needed to save lots of cost.
✔ Function integrated foam patterns could be assembled from several pieces of foam patterns.
✔ Lost foam castings are near-net-shape process
✔ High flexibility through short set-up times
✔ Longer EPS mould service lives, hence lower proportionate tool costs
✔ Assembly and treatment costs are reduced by the omission of the treatment process, installation parts, screw connections, etc.
✔ Expansion of the scope of applications

Metals and Alloys Could Cast by Lost Foam Casting Process
• Gray Cast Iron, Ductile Cast Iron
• Carbon Steel: Low carbon, medium carbon and high carbon steel
• Cast Steel Alloys: Low alloy steel, high alloy steel, special alloy steel
• Aluminium and their alloys
• Brass & Copper.

Industries The Lost Foam Castings Used For:
Just as mentioned above, the lost foam casting is specially suitable to produce the large and thick-wall castings. They are serving mostly the trucks, railroad trains, construction machineries and other heavy machineries with the requirements of complex structure of the desired castings.

Casting Tolerances Reached by Lost Foam Casting Process:
Generally speaking, the casting tolerances of lost foam castings are better than sand casting, but worse than shell mold casting and no-bake casting processes. For our foundry, we basically could achieve the following casting grades. But we would like to talk with you the specific castings and then decide what numbers we can provide for you.
✔ DCT Grade by Lost Foam Casting: CTG9 ~ CTG13
✔ GCT Grade by Lost Foam Casting: CTG5 ~ CTG8

Production ProcessAnnual Capacity / TonsMain MaterialsCasting Weights
Sand Casting6000Gray Iron, Ductile Iron, Aluminium, Brass0.3 kg to 200 kg 
0.66 lbs to 440 lbs
Lost Foam Casting4000Gray Iron, Ductile Iron, Steel Alloys10 kg to 300 kg
 22 lbs to 660 lbs
Investment Casting (Lost Wax Casting)Water Glass Casting3000Carbon Steel, Steel Alloys, Stainless Steel, Brass0.1 kg to 50 kg 
0.22 lbs to 110 lbs
Silica Sol Casting1000Carbon Steel, Steel Alloys, Stainless Steel, Brass0.05 kg to 50 kg
0.11 lbs to 110 lbs
lost foam patterns for casting

Foam Patterns for Casting

lost foam casting patterns-gear box housing

Lost Foam Casting Pattern

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