Custom Investment Casting Centrifugal Pump Housing

Advantages of Custom Investment Casting for Pump Housings

• Net-Shape Production: Minimizes material waste and post-machining

• Tight Tolerances: Achievable dimensional accuracy within ±0.1 mm

• Superior Surface Finish: Ra ≤ 6.3 μm reduces flow resistance

• Complex Geometry Capability: Integrate ribs, contours, and ports without welding

• Material Versatility: Suitable for Inconel, Hastelloy, stainless steels, and cobalt alloys

• Cost-Efficiency: Reduces lead time for low to medium-volume production

Common Applications

• Chemical Transfer Pumps Used in corrosive environments handling acids, solvents, or caustic fluids.

• Seawater Circulation Pumps Require marine-grade corrosion resistance and erosion-resistant geometry.

• Steam Condensate Pumps Demand temperature resistance and high mechanical integrity under pressure.

• Slurry Pumps and Tailings Handling Require reinforced designs to combat abrasion from suspended solids.

Manufacturing Process for Investment Cast Pump Housings

1. Wax Pattern Design Custom wax molds are built from 3D CAD models, incorporating internal channels, flanges, and support ribs.

2. Shell Mold Building Ceramic slurries and refractory stucco are applied to wax assemblies in layers to build a 6–8 mm mold wall.

3. Dewaxing and Shell Firing Wax is removed in an autoclave at ~150°C, followed by shell firing at ~1000°C to strengthen the mold.

4. Alloy Melting and Pouring Metals such as Inconel 625, stainless steel 316, or Hastelloy C-22 are vacuum or air melted and poured into preheated molds.

5. Shell Removal and Cleaning Shells are broken off by vibration and blasting, followed by acid pickling to remove any surface residue.

6. Heat Treatment Solution annealing and aging improve mechanical properties and corrosion resistance.

7. Machining and Finishing Critical faces, threads, and sealing surfaces are completed with CNC machining and EDM.

8. Quality Control CMM, X-ray, pressure testing, and material certification per ASTM and ASME standards.

Materials Commonly Used

• Inconel 625 / 718 – For high-pressure and temperature chemical systems

• Stainless Steel 316 / 316L / 2205 Duplex – For general-purpose and corrosion-resistant applications

• Hastelloy C-276 / C-22 – For severe corrosive media

• Stellite Alloys – For wear-resistant pump surfaces

• Carbon Steels – For cost-sensitive utility water systems

Case Study: Custom Inconel 625 Pump Housing for Seawater Injection

Project Background

Neway AeroTech supplied custom-cast Inconel 625 pump housings for a seawater injection system on an offshore platform. The component required high strength, excellent corrosion resistance in chloride-rich media, and integrated inlet/outlet flanges to minimize welds. The project achieved ±0.03 mm flatness and passed 100% NDT and hydrostatic pressure tests.

Key Performance Benefits

• Corrosion Resistance: Long-term stability in acidic, alkaline, or saltwater environments

• Dimensional Stability: Reduced warping and tolerance stack-up compared to fabrication

• Mechanical Integrity: High-pressure capacity and fatigue resistance

• Design Flexibility: Internal vanes, flow guides, and mounting bosses integrated into the casting

FAQs

1. What alloys are best suited for investment cast pump housings?

2. What tolerances can be achieved with investment casting?

3. Can investment cast pump housings be pressure-tested and certified?

4. What are the benefits of casting vs. fabricated housings?

5. Can you supply low-volume or prototype quantities for custom pump designs?