Product: Centrifugal-pump volute / pump casing
Application: Fluid-handling equipment for ambient-temperature clean water and mildly corrosive service
Material: CF8 cast stainless steel under ASTM A351
Process: Investment casting (lost-wax casting), followed by project-specific machining and inspection
CF8 pump volute and project requirements
This CF8 stainless steel volute forms the casing of a centrifugal pump. The project drawing called for controlled flange interfaces, a formed internal passage and consistent machining allowance on the sealing and mounting features. The specified service involved ambient-temperature clean water and mildly corrosive conditions.
Internal-cavity and casting-soundness work
The curved cavity and changes in wall thickness made core position and shrinkage control important. During sampling, a local wall-thickness deviation led to changes in the wax tooling and water-soluble core location. Radiographic review found isolated shrinkage near a volute corner, and two samples showed minor leakage during hydrostatic testing. The project team revised the gating and feeding arrangement before repeat production.
Verification and outcome
The inspection route included heat-level material checks, first-article dimensional measurement, penetrant testing and hydrostatic testing of every production casing. The specified hydrostatic test was 1.65 MPa for 10 minutes; accepted parts showed no visible leakage. The first-article dimensional report was submitted for review, and the project progressed from sample confirmation through a small production run into repeat supply. For general process considerations, see our pump and valve investment-casting guide.
