Investment Casting in China — Complete Buyer's Guide
Investment casting (lost-wax casting) produces complex metal parts with near-net shape accuracy requiring minimal secondary machining. China's investment casting industry serves aerospace, medical, automotive, and industrial buyers worldwide.
Key Advantages
- Surface finish: Ra 1.6-6.3um
- Tolerances: CT5-CT7 per ISO 8062
- Complex geometry: Internal passages, undercuts, thin walls (0.5mm+)
- Wide material range: Carbon/alloy steels, stainless, aluminum, nickel alloys
The 8-Step Process
- Wax injection into metal die
- Assembly onto wax tree (sprue)
- Ceramic shell building (5-8 coats)
- Flash dewaxing (wax recycled)
- Shell firing at 900-1100 C
- Molten metal pouring into preheated shell
- Shell removal (vibration or water blast)
- Cut-off, grinding, heat treatment, inspection
Material Options
| Category | Grades | Applications |
|---|
| Carbon Steel | WCB, WCC, 20# | Valve bodies, pump parts |
| Stainless Steel | 304, 316L, 17-4PH, CF8M | Food, marine, chemical, medical |
| Nickel Alloys | Inconel 625/718, Hastelloy | Aerospace, oil and gas |
| Aluminum | A356, 6061 | Aerospace brackets |
| Bronze | C84400, C95800 | Marine hardware, bushings |
Chinese IC Hubs
- Dongying / Weifang (Shandong): China's largest IC cluster. Valve and pump castings for global oil and gas.
- Wenzhou (Zhejiang): Precision stainless steel, food-grade and sanitary.
- Suzhou / Kunshan (Jiangsu): Aerospace and medical (AS9100, ISO 13485).
- Guangzhou (Guangdong): Hardware and decorative castings.
Typical Tolerances
| Dimension | Linear Tolerance |
|---|
| Up to 25mm | +/- 0.13mm |
| 25-50mm | +/- 0.18mm |
| 50-100mm | +/- 0.25mm |
| 100-200mm | +/- 0.38mm |
Certifications
- ISO 9001, PED 2014/68/EU
- AS9100D (aerospace)
- ISO 13485 (medical)
- NORSOK M-650 (oil and gas)
- Lloyd's / DNV / ABS (marine)
Sourcing Checklist
- Water-based vs alcohol-based shell system
- NDT in-house: X-ray, dye penetrant, mag particle
- Heat treatment furnace capacity for your part size
- Spectrometer report with each heat
- Typical MOQ: 200-500 pieces per part number