Investment Casting Foundry | Sand Casting

Stainless Steel Castings, Grey Iron Castings, Ductile Iron Castings

Grey Cast Iron Investment Casting Product

Short Description:

Cast Steel: Grey Cast Iron

Casting Process: Lost Wax Investment Casting

Unit Weight of Casting: 11.60 kg

Available Surface Treatment: Painting, Anodizing, Passivation, Electroplating, Zinc-plating, Hot-Zinc-Plating, Polishing, Electro-Polishing, Nickel-Plating, Blackening, Geomet, Zintek

Heat Treatment: Quenching, Tempering, Normalizing, Carburization, Nitriding


China OEM custom gray cast iron castings produced by lost wax investment casting with CNC machining and surface treatment services. Available inspection methods: dimension testing by CMM, non-destructive testing, chemical composition, mechanical properties, hardness testing, static balancing, dynamic balancing, air pressure and water pressure. 

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OEM custom grey iron castings produced by precision lost wax investment casting and CNC machining. 

Thanks to its ease of machining, high compressive strength, better thermal conductivity and excellent vibration absorption, the gray cast iron is one of the most widely used casting metal for a very long time, even in current industry production. Carbon content is by far the most important element for gray iron (usually 2% to 4%) to create tensile strength and machinability. When molten cast iron solidifies some of the carbon precipitates as graphite, forming tiny, irregular flakes within the crystal structure of the metal which enhances the desirable properties of cast iron, the flakes disrupt the crystal structure leading to cast iron's characteristic brittleness.

The development of gray cast iron is mainly driven by high strength. In the past, the main way to improve the performance of gray cast iron was inoculation. In recent years, the main approach now is to focus on alloying, and in order to improve casting performance, many gray iron foundries use cast iron with a higher carbon equivalent. This is particularly important for low alloy cast iron. Therefore, the gray cast iron is suitable material to produce iron casting parts of engine block, machinery housing, machine base, counter weights, stove parts, boiler parts, pump shells and so on.

Mechanical Properties of Cast Gray Iron
Tensile Strength of Separately Cast Samples of Gray Cast Irons
Material Designation GG-10, EN-GJL-100 GG-15, EN-GJL-150 GG-20, EN-GJL-200 GG-25, EN-GJL-250 GG-30, EN-GJL-300 GG-35, EN-GJL-350
Tensile Strength (MPa) ≥100 ≥150 ≥200 ≥250 ≥300 ≥350
Tensile Strength of Cast-on Samples of Gray Cast Irons
Material Designation Wall Thickness of Casting (mm) Tensile Strength (MPa) ≥
Sample Bar Dia. (mm) Sample Block (mm) Castings (Reference)
φ30 φ50 R15 R25
HT150, GG-15, EN-GJL-150 20-40 130 / 120 / 120
40-80 115 115 110 / 105
80-150 / 105 / 100 90
150-300 / 100 / 90 80
HT200, GG-20, EN-GJL-200 20-40 180 / 170 / 165
40-80 160 155 150 / 145
80-150 / 145 / 140 130
150-300 / 135 / 130 120
HT250, GG-25, EN-GJL-250 20-40 220 / 210 / 205
40-80 200 190 190 / 180
80-150 / 180 / 170 165
150-300 / 165 / 160 150
HT300, GG-30, EN-GJL-300 20-40 260 / 250 / 245
40-80 235 230 225 / 215
80-150 / 210 / 200 195
150-300 / 195 / 185 180
HT350, GG-35, EN-GJL-350 20-40 300 / 290 / 285
40-80 270 265 260 / 255
80-150 / 240 / 230 225
150-300 / 215 / 210 205
Tensile Strength of Gray Iron Casting in Different Wall Thickness
Cast Wall Thickness (mm) Material Designation
GG-10, EN-GJL-100 GG-15, EN-GJL-150 GG-20, EN-GJL-200 GG-25, EN-GJL-250 GG-30, EN-GJL-300 GG-35, EN-GJL-350
Tensile Strength (MPa) ≥
2.5-4.0 130 175 220 / / /
4.0-10 270
10-20 100 145 195 240 290 340
20-30 90 130 170 220 250 290
30-50 80 120 160 200 230 260

Cast iron, mainly including the gray cast iron and ductile (nodular) cast iron are mainly used for casting by processes of sand casting, shell moulding casting, coated sand casting or lost foam casting. However, for some special situation, the lost wax investment casting process is also used due to their fine surface and higher accuracy. At RMC, we also have tha ability of casting gray iron and ductile with precision lost wax investment casting using silica sol and water glass for shell building. 

When cast iron is slowly cooled, the cementite decomposes into iron and carbon in the form of graphite which is called graphitization. Cast irons where a large percentage of cementite is decomposed by graphitization are called grey cast irons. Cast iron in which graphitization has not taken place, i. e, all the carbon is in the combined form, is called white cast iron. The graphitization process requires time and therefore, when liquid cast iron is cooled rapidly, white cast iron would result. White cast iron is comparable in properties to that of high carbon steels. However, it is highly brittle and as such is not used for structural parts. It is useful for parts where abrasive wear is present. Tensile strength varies between 170 to 345 MPa and is usually about 240 MPa. The hardness ranges from 350 to 500 BHN. In view of the very high hardness, the machinability is poor and is commonly finished by grinding.

Gray Iron Comparison Casting Thickness/mm Chemical Composition(%)
China(GB/T 9439-1988) ISO 185:1988 USA ASTM A48/A48M-03(2008) Europe(EN 1561:1997) C Si Mn P        ≦ S        ≦
HT100 (HT10-26) 100 No.20 F11401 GJL-100 JL-1010 - 3.4-3.9 2.1-2.6 0.5-0.8 0.3 0.15
HT150 (HT15-33) 150 No.25A F11701 GJL-150 JL-1020 <30     30-50     >50 3.3-3.5 3.2-3.5 3.2-3.5 2.0-2.4 1.9-2.3 1.8-2.2 0.5-0.8 0.5-0.8 0.6-0.9 0.2 0.12
HT200 (HT20-40) 200 No.30A F12101 GJL-200 JL-1030 <30     30-50     >51 3.2-3.5 3.1-3.4 3.0-3.3 1.6-2.0 1.5-1.8 1.4-1.6 0.7-0.9 0.8-1.0 0.8-1.0 0.15 0.12
HT250 (HT25-47) 250 No.35A F12401 No.40A F12801 GJL-250 JL-1040 <30     30-50     >52 3.0-3.3 2.9-3.2 2.8-3.1 1.4-1.7 1.3-1.6 1.2-1.5 0.8-1.0 0.9-1.1 1.0-1.2 0.15 0.12
HT300   (HT30-54) 300 No.45A F13301 GJL-300 JL-1050 <30     30-50     >53 2.9-3.2 2.9-3.2 2.8-3.1 1.4-1.7 1.2-1.5 1.1-1.4 0.8-1.0 0.9-1.1 1.0-1.2 0.15 0.12
HT350   (HT35-61) 350 No.50A F13501 GJL-350 JL-1060 <30     30-50     >54 2.8-3.1 2.8-3.1 2.7-3.0 1.3-1.6 1.2-1.5 1.1-1.4 1.0-1.3 1.0-1.3 1.1-1.4 0.1 0.1

Investment casting (or lost wax casting) refers to the formation of ceramic around the wax patterns to create a multi or single part mold to receive molten metal. This process utilizes an expendable injection molded wax pattern process to achieve complex forms with exceptional surface qualities. Precision investment castings can achieve exceptional accuracy for both small and large casting parts in a wide range of materials.

To create a mold, a wax pattern, or cluster of patterns, is dipped into ceramic material several times to build a thick shell. De-wax process is then followed by the shell dry process. The wax-less ceramic shell is then produced. Molten metal is then poured into the ceramic shell cavities or cluster, and once solid and cooled, the ceramic shell is broken off to reveal the final cast metal object.

Investment Casting Technical Data at RMC
R&D Software: Solidworks, CAD, Procast, Pro-e
Lead Time for Development and Samples: 25 to 35 days
Molten Metal Ferritic Stainless Steel, Martensitic Stainless Steel, Austenitic stainless steel, Precipitation Hardening Stainless Steel, Duplex Stainless Steel
Carbon Steel, Alloy Steel, Tool Steel, Heat Resistant Steel, 
Nickle-base Alloy, Aluminium Alloy, Copper-base Alloy, Cobalt-base Alloy
Metal Standard ISO, GB, ASTM, SAE, GOST EN, DIN, JIS, BS
Material for Shell Building Silica Sol (Precipitated Silica )
Water Glass (Sodium Silicate)
Mixtures of Silica Sol and Water Glass
Technical Parameter Piece Weight: 2 gram to 200 kilo gram
Max Dimension: 1,000 mm for Diameter or Length
Min Wall Thickness: 1.5mm
Casting Roughness: Ra 3.2-6.4, Machining Roughness: Ra 1.6
Tolerance of Casting: VDG P690, D1/CT5-7
Tolerance of Machining: ISO 2768-mk/IT6
Inner Core: Ceramic Core, Urea Core, Water Soluble Wax Core
Heat Treatment Normalizing, Tempering, Quenching, Annealing, Solution, Carburization.
Surface Treatment Polishing, Sand / Shot Blasting, Zinc Plating, Nickel Plating, Oxidation Treatment, Phosphating, Powder Painting, Geormet, Anodizing
Dimension Testing CMM, Vernier Caliper, Inside Caliper. Depth Gage, Height Gage, Go/No go Gage, Special Fixtures
Chemical Inspection Chemical Compostion Analysis (20 chemical elements), Cleanliness Inspection, X-ray Radiographic Inspection, Carbon-Sulfur Analyser
Physical Inspection Dynamic Balancing, Static Blancing, Mechanical Properties (Hardness, Yield Strength, Tensile Strength), Elongation
Production Capacity More than 250 tons per month, more than 3,000 tons annually.
custom sand casting products

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