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Investment Casting

NGR offers top-notch custom ferrous and non-ferrous investment casting parts and components for diverse industries. Investment casting proves to be an exceedingly adaptable method, suitable for both uncomplicated and intricate, as well as low and high-volume production requirements. Our expertise lies in crafting investment castings from a variety of materials, including stainless steel, duplex stainless steel, titanium, carbon steel, tool steel, and aluminum alloys, among others. Our capabilities span from producing parts weighing just a few grams to those approaching nearly one metric ton. Additionally, we extend a comprehensive range of secondary services, encompassing machining, surface finishing, and more.

What Is Investment Casting?

Investment casting involves the creation of a ceramic shell around a wax pattern, serving as a mold for pouring molten metal. After crafting wax patterns, they are melted away within the gating system, surrounded by a combination of slurry and sand to construct a layered shell. Subsequently, the molten metal, such as stainless steel, aluminum, or similar materials, is introduced to fill the void left by the melted wax patterns.

What does the Investment Casting process entail?

Investment casting entails the fabrication of an initial wax model, gradually constructing layers of plaster and other materials to form a robust shell enveloping the model. Following the wax's removal, molten gold or bronze is poured into the mold, resulting in a flawless reproduction of the original wax pattern. Investment casting offers cost-effective solutions for intricate undercuts, precise detailing, and a refined surface finish compared to machining methods. In many instances, investment casting stands as the sole economically viable means of producing the part.

Tolerance of Investment Casting

Typical linear tolerances in investment casting typically follow these general guidelines: For dimensions up to 1 inch, allow a tolerance of +/- 0.010 inch. For each additional inch up to ten inches, apply a tolerance of +/- 0.003 inch per inch. When dealing with dimensions greater than ten inches, a tolerance of +/- 0.005 inch per inch is acceptable. Keep in mind that secondary processes like straightening and sizing can yield even tighter dimensional tolerances.

Dimensions
Normal Tolerance of Investment Casting
Up to 2”
+/- .013”
Up to 3”
+/- .016”
Up to 4”
+/- .019”
Up to 5”
+/- .022”
Up to 6”
+/- .025”
Up to 7”
+/- .028”
Up to 8”
+/- .031”
Up to 9”
+/- .034”
Up to 10”
+/- .037”
> 10”
allow +/- .005” per inch
Up to 1”
+/- .010”

Advantages of Investment Casting

  • A mold surface with minimal roughness and a material possessing significant refractory strength and chemical inertness can result in surface castings of excellent quality.

  • When there is minimal metal machining and a decreased generation of metal shavings, the mass accuracy factor for the castings can achieve a noteworthy range between 0.85 and 0.95.

  • In investment casting, materials are employed that do not require the mold to be disassembled during removal. These mold materials possess excellent flame-retardant properties and can facilitate better metal fill-ins when preheated to high temperatures before the pouring process.

  • The metal content in the investment casting process typically ranges from 90% to 95%, which is a proportion similar to that found in injection molding.

  • Reduced environmental risks associated with the foundry procedure.

  • Available sizes ranging from 0.1 inches to over 3 feet.

  • Weight options encompassing a spectrum from a few grams to one metric ton.

  • Attainment of an exceptionally smooth surface finish.

  • Strict adherence to tight tolerance standards.

  • Dependable process controls ensuring consistency and repeatability.

  • Versatility in both design and casting options.

  • Streamlined and effective production processes.

  • Cost-effective tooling solutions.

  • A wide array of material choices.

Material
Grade
Common Application
Stainless Steel
304

SS 304 serves as the industry standard for cleanliness and corrosion resistance in medical, plumbing, irrigation, mining, and petrochemical sectors.

316

SS316 excels in automotive, food, dairy, and petrochemical applications due to its outstanding corrosion resistance, making it the ideal material for components like housings, gears, and plates.

304L / 316L

Like other 300 series steels, low carbon content enhances both malleability and corrosion resistance. Key industries include food & dairy, medical, and petrochemical.

410 / 416

Housings, bushings, handles, brackets: 400 series steels offer high strength and excellent machinability. They are prone to breaking rather than bending under extreme pressure. These steels find ideal applications in industries such as automotive, food & dairy, and various machine tools.

17-4

Highly robust, suitable for military and diverse machine tool applications.

Duplex Stainless Steel
2205

Duplex stainless steel 2205 exhibits a unique two-phase microstructure, comprising both ferritic and austenitic stainless steel phases. Notably, it contains a higher nitrogen content compared to other duplex stainless steel grades.


Super Duplex Stainless Steel
2507

Desalination, marine, pulp & paper, chemical processing, pressure vessels, heat exchangers, piping, and both onshore and offshore oil and gas industries.

Zeron 100

Desalination, flue-gas desulfurization, oil and gas, pollution control, chemical, pharmaceutical, mining, pulp and paper, power generation, and marine industries.

Titanium
Grade 2

Chemical process, marine etc.

Grade 5

Aerospace, medical, marine, chemical processing, and oil field services industries.

Carbon Steels
1000 series

Among common carbon steels, this one is the softest and tends to bend rather than break under extreme pressure. It's often employed in crafting cranks, handles, and braces.

4100 series

A high-strength material employed when avoiding deformation is crucial. It's commonly used in casting firearm components and ratchets.

8600 series

The 8600 series is stronger than the 1000 series but exhibits bending rather than breaking. It's a common choice for casting firearm components, housings, and nozzles.

Tool Steels
A2, S7, D2

Utilized for applications with higher heat requirements to minimize distortion, but lacks the corrosion resistance of stainless steel.

Aluminum Alloys
A356

Housings, covers, plates: Aluminum combines lightweight properties with exceptional corrosion resistance, akin to stainless steel.

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