OEM Custom Stainless Steel Water Glass Investment Casting from China Stainless Steel Foundry

In the investment casting process, the water glass binder and coating have stable performance, low price, short shell-making cycle and convenient application. The water glass shell making process is suitable for the production of investment castings such as carbon steel, low-alloy steel, cast iron, copper and aluminum alloys that require less surface quality.

Water glass, also known as Sodium Silicate, is a kind of soluble alkali metal silicate, which is glassy in solid state and forms a water glass solution when dissolved in water. According to the difference of the alkali metals contained, there are two types of potassium water glass and soda water glass. The latter is easily soluble in water, contains less impurities, and has stable performance. Therefore, the water glass for investment casting is sodium water glass, namely Na20·mSiO2, A transparent or translucent colloidal aqueous solution formed after hydrolysis. The main chemical components of water glass are silicon oxide and sodium oxide. In addition, it also contains a small amount of impurities. Water glass is not a single compound, but a mixture of multiple compounds.

Stainless steel has a minimum chromium content of 10.5%, making it more resistant to corrosive liquid environments and to oxidation. It is highly corrosion resistant and wear resistant, provides excellent machinability, and is well-known for its aesthetic appearance. Stainless steel investment castings are "corrosion-resistant" when used in liquid environments and vapors below 1200°F (650°C) and "heat-resistant" when used above this temperature.

The base alloy elements of any nickel-base or stainless steel investment casting are chromium, nickel, and molybdenum (or "moly"). These three components will determine the casting's grain structure and mechanical properties and will be instrumental in the casting's ability to combat heat, wear, and corrosion.

Our foundry can manufacture custom stainless steel investment castings that match your exact design specifications. For parts ranging from tens of grams to tens of kilograms or more, we provide tight tolerances and consistent part to part repeatability.

Commonly, the stainless steel should be cast by the investment precision casting process with the silica sol as the bond. The stainless steel silica sol castings have a very high grade of precision surface and performance.

Due to its unique physical properties, stainless steel castings are popular in a wide range of applications, especially those in harsh environments. Common markets for stainless steel investment castings include oil and gas, fluid power, transportation, hydraulic systems, food industry, hardware and locks, agriculture...etc.

Investment (lost wax) casting is a method of precision casting complex near-net-shape details using replication of wax patterns. Investment casting or lost wax is a metal forming process that typically uses a wax pattern surrounded by a ceramic shell to make a ceramic mold. When the shell dries, the wax is melted away, leaving only the mold. Then the casting component is formed by pouring molten metal into the ceramic mold.

The process is suitable for repeatable production of net shape components from a variety of different metals and high performance alloys. Although generally used for small castings, this process has been used to produce complete aircraft door frames, with steel castings of up to 500 kgs and aluminium castings of up to 50 kgs. Compared to other casting processes such as die casting or sand casting, it can be an expensive process. However, the components that can be produced using investment casting can incorporate intricate contours, and in most cases the components are cast near net shape, so require little or no rework once cast.

Silica sol casting process is the main steel investment casting process of RMC investment casting foundry. We have been developing new technology of adhesive material to achieve much more economical and effective adhesive material to build the slurry shell. It is a overwhelming trend that Silica sol casting process replaces the rough inferior water glass process, especially for stainless steel casting and alloy steel casting. Besides the innovated molding material, the silica sol casting process has also being innovated to much steadier and less heat expanding.

▶ Ferrous and Non-ferrous Materials for Investment Casting, Lost Wax Casting Process:
• Gray Iron:  HT150, HT200, HT250, HT300, HT350; GJL-100, GJL-150, GJL-200, GJL-250, GJL-300, GJL-350; GG10~GG40.
• Ductile Iron or Nodular Iron: GGG40, GGG50, GGG60, GGG70, GGG80; GJS-400-18, GJS-40-15, GJS-450-10, GJS-500-7, GJS-600-3, GJS-700-2, GJS-800-2; QT400-18, QT450-10, QT500-7, QT600-3, QT700-2, QT800-2;
• Carbon Steel:  AISI 1020  - AISI 1060,
• Steel Alloys: ZG20SiMn, ZG30SiMn, ZG30CrMo, ZG35CrMo, ZG35SiMn, ZG35CrMnSi, ZG40Mn, ZG40Cr, ZG42Cr, ZG42CrMo...etc on request.
• Stainless Steel: AISI 304, AISI 304L, AISI 316, AISI 316L, 1.4404, 1.4301 and other stainless steel grade.
• Brass, Red Copper, Bronze or other Copper-based alloy metals
• Other Materials as per your unique requirements or according to ASTM, SAE, AISI, ACI, DIN, EN, ISO, and GB standards

▶ Capabilities of Investment Casting Foundry
• Max Size: 1,000 mm × 800 mm × 500 mm
• Weight Range: 0.5 kg - 100 kg
• Annual Capacity: 2,000 tons
• Bond Materials for Shell Building: Silica Sol, Water Glass and their mixtures.
• Tolerances: On Request.

▶ Main Production Procedure
• Patterns & Tooling Design → Metal Die Making → Wax Injection → Slurry Assembly → Shell Building → De-Waxing  → Chemical Composition Analysis → Melting & Pouring → Cleaning, Grinding & Shot Blasting → Post Processing or Packing for Shipment

▶ Inspecting Lost Wax Castings
• Spectrographic and manual quantitative analysis
• Metallographic analysis
• Brinell, Rockwell and Vickers hardness inspection
• Mechanical property analysis
• Low and normal temperature impact testing
• Cleanliness inspection
• UT, MT and RT inspection

▶ Post-Casting Process
• Deburring & Cleaning
• Shot Blasting / Sand Peening
• Heat Treatment: Normalization, Quench, Tempering, Carburization, Nitriding
• Surface Treatment: Passivation, Anodizing, Electroplating, Hot Zinc Plating, Zinc Plating, Nickel Plating, Polishing, Electro-Polishing, Painting, GeoMet, Zintec.
• Machining: Turning, Milling, Lathing, Drilling, Honing, Grinding.

▶ Advantages of Investment Casting Components:
• Excellent and smooth surface finish
• Tight dimensional tolerances.
• Complex and intricate shapes with design flexibility
• Capability to cast thin walls therefore a lighter casting component
• Wide selection of cast metals and alloys (ferrous and non-ferrous)
• Draft is not required in the molds design.
• Reduce the need for secondary machining.
• Low material waste.

▶ Why You Choose RMC for Custom Lost Wax Casting Parts?
• Full solution from one single supplier ranging customized pattern design to finished castings and secondary process including CNC machining, heat treatment and surface treatment.
• Costdown proposals from our professional engineers based on your unique requirement.
• Short leadtime for prototype, trial casting and any possible technical improvement.
• Bonded Materials: Silica Col, Water Glass and their mixtures.
• Manufacturing flexibility for small orders to mass orders.
• Strong outsourcing manufacturing capabilities.

To know better about our capabilities of lost wax casting process, please click the following picture to turn to our page of Investment Casting Capabilities: