Investment Casting Glossary

Process & Workflow

• Investment Casting

• Definition: A precision casting process using expendable wax patterns to create ceramic shells for near-net-shape metal parts.

• Notes/Applications: High dimensional accuracy, smooth surface finish, complex thin-walled geometries.

• Lost Wax Casting

• Definition: Core method of investment casting where wax patterns are removed (dewaxed) from the ceramic shell before pouring.

• Notes/Applications: Ideal for stainless, alloy steel, nickel-based alloys, bronze.

• Precision Casting

• Definition: Casting methods delivering tight tolerances and fine surfaces; investment casting is the primary form.

• Notes/Applications: Reduces machining allowance and lead time.

• Silica Sol Process

• Definition: Shell-making route using silica sol binders for ceramic shells.

• Notes/Applications: Superior surface finish and dimensional stability, widely used for stainless steel parts.

• Shell Making

• Definition: Repeated dipping and stuccoing of wax patterns to form a ceramic shell.

• Notes/Applications: Shell strength and permeability drive filling quality and surface integrity.

• Dewaxing

• Definition: Heating to remove wax from the shell cavity (e.g., steam autoclave).

• Notes/Applications: Prevent shell cracking and distortion.

• Pouring (Casting)

• Definition: Introducing molten metal into the shell and allowing it to solidify.

• Notes/Applications: Pour temperature, speed, and gating design control defects and soundness.

• Gating/Riser System

• Definition: Channels and reservoirs that guide melt flow and provide feed metal during solidification.

• Notes/Applications: Controls turbulence, inclusions, and shrinkage porosity.

• Fettling/Grinding

• Definition: Removal of gates/risers and cleaning up as-cast surfaces.

• Notes/Applications: Avoid excessive grinding that affects tolerance and flatness.

• Shot Blasting/Sand Blasting

• Definition: Projectile media cleaning to remove scale and adhered ceramic.

• Notes/Applications: Influences surface roughness and residual stress.

• Deburring

• Definition: Removal of sharp edges and burrs.

• Notes/Applications: Improves assembly, safety, and sealing.

• Heat Treatment

• Definition: Thermal processes (e.g., solution anneal, aging) to refine microstructure and properties.

• Notes/Applications: Duplex steels require phase balance control.

• Machining (CNC)

• Definition: Post-casting operations (turning, milling, drilling) to final dimensions.

• Notes/Applications: Stable fixturing and distortion control are essential.

• Surface Finishing/Polishing/Passivation

• Definition: Finishes that improve roughness and corrosion resistance.

• Notes/Applications: Food equipment often requires mirror polish and passivated surfaces.

• Non-Destructive Testing (NDT)

• Definition: Inspection methods that do not damage parts.

• Notes/Applications: PT, MT, UT according to class/standard requirements.

• Dimensional Inspection / First Article Inspection (FAI)

• Definition: Verification of dimensions using gauges and CMM; full first-piece validation.

• Notes/Applications: Compliant with drawing GD&T requirements.

• Tooling/Fixtures/Die/Wax Pattern

• Definition: Production tooling and wax models that define final geometry.

• Notes/Applications: Drives repeatability and dimensional chain control.

Materials & Grades

• Stainless Steel

• Definition: Corrosion-resistant steels with Cr ≥ 10.5%.

• Notes/Applications: Pump/valve bodies, food equipment; common cast grades CF8, CF8M, CF3M, 1.4408, 1.4409, SCS13, SCS14.

• Duplex Stainless Steel

• Definition: Dual-phase (austenite + ferrite) stainless steels with high strength and pitting/crevice resistance.

• Notes/Applications: Typical grades 2205, 2507, 1.4517, 1.4469.

• Carbon Steel / Alloy Steel

• Definition: Ferrous alloys with tailored strength/toughness via heat treatment.

• Notes/Applications: Structural parts, automotive, valve bodies.

• Nickel-Based Alloy

• Definition: Alloys designed for high-temperature and highly corrosive environments.

• Notes/Applications: Requires precise pouring control due to high superheat and crack sensitivity.

• Copper/Bronze

• Definition: Nonferrous alloys with good corrosion resistance and thermal conductivity.

• Notes/Applications: Marine and valve components; vigilance on porosity and dezincification (for brasses).

Products & Components

• Pump Body/Casing/Housing

• Definition: Pressure-retaining flow passage of a pump.

• Notes/Applications: Sealing faces and flow channels require consistent wall thickness.

• Pump Cover

• Definition: Cover component closing the pump chamber or providing access.

• Notes/Applications: Flatness and gasket surface quality are critical.

• Impeller

• Definition: Rotating energy-transfer element in pumps.

• Notes/Applications: Dynamic balance, blade thickness, and surface roughness.

• Double Suction Impeller

• Definition: Impeller with dual inlets for reduced axial force and higher flow.

• Notes/Applications: Symmetry and coaxiality control.

• Volute Casing

• Definition: Spiral-shaped pump casing that collects flow to the discharge.

• Notes/Applications: Smooth geometry for hydraulic efficiency.

• Liquid Ring Vacuum Pump Casing

• Definition: Casing for liquid ring vacuum pumps.

• Notes/Applications: Corrosion resistance, concentricity, and leak tightness.

• Rotary Lobe Pump Rotor

• Definition: Positive-displacement rotor set, often for sanitary services.

• Notes/Applications: Smooth surfaces and tight clearances; stainless/duplex preferred.

• Plunger Pump Casting

• Definition: High-pressure pump components.

• Notes/Applications: Shrinkage control, inclusions prevention, and consistent heat treatment.

• Valve Body

• Definition: Pressure-containing body of a valve.

• Notes/Applications: Pressure class, cavity geometry, and NDT class.

• Ball Valve Body

• Definition: Body casting for ball valves.

• Notes/Applications: Seat pocket accuracy and sealing surfaces.

• Knife Gate Valve Body

• Definition: Body for knife gate valves.

• Notes/Applications: Flatness and gate path straightness.

• Valve Plug (for Plug Valves)

• Definition: Tapered or cylindrical control element.

• Notes/Applications: Roundness, taper tolerance, and surface finish.

• Turbo/Turbine Housing (Turbocharger)

• Definition: Hot-side housing that directs exhaust flow to the turbine wheel.

• Notes/Applications: Heat-resistant alloys, thermal fatigue, and uniform wall thickness.

• Burner Components / Flare Component

• Definition: Flow-directing and mixing parts in burners.

• Notes/Applications: High-temperature oxidation resistance and thermal shock durability.

• Food Equipment Body & Cover (e.g., Meat Grinder Body/Cover)

• Definition: Structural casings for food machinery.

• Notes/Applications: Hygienic surface finish (mirror polish), passivation, easy-clean design.

• Automotive Turbine Housing

• Definition: Turbocharger housing for automotive applications.

• Notes/Applications: IATF 16949 compliance, heat resistance, dimensional stability.

Capabilities & Parameters

• Unit Weight Range

• Definition: Weight of individual castings producible.

• Notes/Applications: Typically 0.1–120 kg (some lines 2–130 kg); impacts gating and handling.

• Annual Capacity

• Definition: Plant's yearly output in tonnage.

• Notes/Applications: About 2,000 tons; supports stable lead times.

Certifications & Quality Systems

• ISO 9001

• Definition: Quality management system standard.

• Notes/Applications: Process control and continuous improvement.

• ISO 14001

• Definition: Environmental management system.

• Notes/Applications: Emissions control and compliance.

• ISO 45001

• Definition: Occupational health and safety management.

• Notes/Applications: Risk assessment and safety training.

• IATF 16949

• Definition: Automotive quality management system.

• Notes/Applications: APQP, PPAP, MSA, SPC requirements.

• TUV / PED / AD W2000

• Definition: European pressure equipment directive and related approvals.

• Notes/Applications: Market access for pressure-containing components.

• Lloyd's Register (LR)

• Definition: Classification and certification for marine applications.

• Notes/Applications: Material and inspection requirements for shipbuilding.

Inspection & Quality Terms

• Surface Roughness (Ra, Rz)

• Definition: Numeric indicators of surface finish.

• Notes/Applications: Affects hydraulic efficiency and cleanability.

• Dimensional/Geometric Accuracy (GD&T)

• Definition: Size tolerances and form/position controls.

• Notes/Applications: CMM verification for critical features.

• Metallographic Examination

• Definition: Microscopic evaluation of microstructure.

• Notes/Applications: Duplex austenite/ferrite phase balance.

• Chemical/Spectral Analysis

• Definition: Composition verification via OES or wet chemistry.

• Notes/Applications: Material grade compliance.

• Mechanical Properties Testing

• Definition: Tensile, yield, elongation, impact tests.

• Notes/Applications: Correlates to heat treatment and solidification.

• Dye Penetrant Testing (PT)

• Definition: Surface-breaking defect detection using penetrants.

• Notes/Applications: Suited for non-magnetic materials and finish-critical surfaces.

• Magnetic Particle Testing (MT)

• Definition: Near-surface defect detection for ferromagnetic materials.

• Notes/Applications: Not applicable to austenitic stainless.

• Ultrasonic Testing (UT)

• Definition: Volumetric inspection using sound waves.

• Notes/Applications: Sensitive to geometry and coupling quality.

• Pressure/Leak Testing

• Definition: Proof and leak integrity tests (hydrostatic, pneumatic, helium).

• Notes/Applications: Critical for pump/valve bodies and housings.

• Design for Manufacturability (DFM)

• Definition: Design evaluation for casting feasibility and cost.

• Notes/Applications: Wall thickness, draft angles, generous radii.

• Traceability / Lot Control

• Definition: End-to-end tracking from raw material to finished goods.

• Notes/Applications: Heat/lot numbers linked to test reports.

Delivery & Collaboration

• OEM / Customization

• Definition: Built-to-print or built-to-spec manufacturing.

• Notes/Applications: NDAs, dedicated tooling.

• Sampling / Prototyping

• Definition: Low-volume builds to validate design and process.

• Notes/Applications: FAI, capability checks.

• Low- to Mass-Production

• Definition: Ramp-up to stable serial production.

• Notes/Applications: Process capability (Cpk) and yield targets.

• Cost Optimization

• Definition: Reducing total cost via DFM, alloy selection, and process integration.

• Notes/Applications: Minimize machining, consolidate features.

• Subcontract Machining / Supply Chain

• Definition: Outsourced machining or finishing operations.

• Notes/Applications: Incoming inspection and consistency control.