Centrifugal pump open impeller of stainless steel by investment casting, CNC machining and dynamic balancing.
The Steps of Investment Casting Process:
During the investment casting process, a wax pattern is coated with a ceramic material, which, when hardened, adopts the internal geometry of the desired casting. In most cases, multiple parts are cast together for high efficiency by attaching individual wax patterns to a central wax stick called a sprue. The wax is melted out of the pattern – which is why it is also known as the lost wax process – and molten metal is poured into the cavity. When the metal solidifies, the ceramic mold is shaken off, leaving the near net shape of the desired casting, followed by finishing, testing and packaging.
Stainless steel is often divided into martensitic stainless steel, ferritic stainless steel, austenitic stainless steel, austenitic-ferritic (duplex) stainless steel and precipitation hardening stainless steel according to the state of microstructure. In addition, according to the chemical compositions, it can be divided into chromium stainless steel, chromium nickel stainless steel and chromium manganese nitrogen stainless steel, etc.
| 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. |
Casting Tolerance Could Reached by Investment Casting:
According to the different binder materials used for making the shell, the investment casting could be divided into silica sol casting and water glass casting. The silica sol investment casting process have better Dimensional Casting Tolerances (DCT) and Geometrical Casting Tolerances (GCT) than water glass process. However, even by same casting process, the Tolerance Grade will be different from each cast alloy due to their various castability. Our foundry would like to talk with you if you have special request on the required tolerances. Here in the following are the general tolerances grade we could reach both by silica sol casting and water glass casting processes separately:
- ✔ DCT Grade by Silica Sol Lost Wax Casting: DCTG4 ~ DCTG6
- ✔ DCT Grade by Water Glass Lost Wax Casting: DCTG5 ~ DCTG9
- ✔ GCT Grade by Silica Sol Lost Wax Casting: GCTG3 ~ GCTG5
- ✔ GCT Grade by Water Glass Lost Wax Casting: GCTG3 ~ GCTG5
General Commerial Terms
- • Main workflow: Inquiry & Quotation → Confirming Details / Cost Reduction Proposals → Tooling Development → Trial Casting → Samples Approval → Trial Order → Mass Production → Continuous Order Proceeding
- • Leadtime: Estimatedly 15-25 days for tooling development and estimatedly 20 days for mass production.
- • Payment Terms: To be negotiated.
- • Payment methods: T/T, L/C, West Union, Paypal.
