Increase your foundry's pie with via casting conversions.

Foundries can increase their current markets and expand to new ones by converting metal fabrications, forgings and weldments to cast metal components.

Casting prices continue to decrease. End-users want their components faster and at reduced prices, and they are searching the global marketplace to find suppliers to accommodate them. For foundries to maintain or increase their market share in this era of heightened cost competition, they can either slash prices and become entrenched in a price bidding war (one they may not win or "win" only at a marginal benefit), or they can seek to broaden the markets for their casting capabilities.

One road to increasing market share that some foundries have begun to travel regularly is the conversion of metal fabrications, forgings and weldments to cast metal components. When possible, these conversions result in consolidated parts, reduced weight, lower cost, and, most importantly, a new market for metal castings (not just stolen business from another foundry).

But what metal components can be converted to castings? According to Michael Gwyn, Pelton Casteel, Milwaukee, there is a qualification process for converting fabrications, weldments and forgings to castings (as discussed in the CMI course "Cost-Effective Casting Design"). A foundry first must determine the potential volume (tons, sales and margin) a component could provide to its operation if it was converted to casting, and then whether it is worth the engineering and advance quality planning effort needed to secure the job. Then, a foundry must determine the applicability of a component to its operation, including the size, weight and surface area-to-weight ratio, and if existing molding and coremaking processes will provide the required sand-to-metal ratios, cosmetic appearance and dimensional requirements. Last, a foundry must establish design boundaries for the component, including: part function; load types, magnitudes and locations; shape constraints, such as functional surfaces and free surfaces; material constraints; ramp-up time; and a quality system.

Following are some examples of casting conversions that have appeared in the Castings in Action department of Engineered Casting Solutions, the magazine published by AFS for design engineers and purchasers of metal castings. Spanning various processes and alloys, these conversions demonstrate the success of some foundries in broadening the markets they serve and expanding the total customer base for castings.

Cast Component:. An oil cooler for an Iveco truck engine.

Material: 319 aluminum alloy.

Process: Lost foam casting.

Casting Supplier: Cagiva Group, Dongo, Como, Italy.

* The component was redesigned for lost foam casting and achieved a 15% weight reduction by casting-in seven bolt holes, two side holes and open holes without draft, as well as by reducing wall thickness to 4 mm.

* The component was redesigned to provide a 45% reduction in machining time by eliminating five plugs, tapping engine mold holes directly, and creating the internal oil and water passage as-cast, instead of the previous machining approach.

* Casting design modifications netted a 28% cost reduction as well as the elimination of potential leak problems by removal of the plugs.

Cast Component: A cellular phone keypad and display enclosures for NTT DoCoMo.

Material: AZ-91D magnesium alloy.

Process: Thixotropic molding.

Casting Supplier: Colcoat Co., Ltd., Tokyo, Japan.

* This component was cast by injecting semi-solid state magnesium into a closed die in a similar manner to plastic injection molding.

* The component's walls are between 0.8 and 1.0 mm thick, with a total casting weight of 105 grams.

* Previously designed as a plastic part, the redesign to magnesium improved the component's rigidity and impact resistance, while providing electro-magnetic interference shielding without external coatings or plating.

Cast Component: A fan frame hub for the GE CF-6-80C engine for Boeing's 747, 767 and MD-11 aircraft.

Material: Titanium.

Process: Investment casting.

Casting Supplier: Precision Castparts Corp. (PCC), Portland, Oregon

* This single 52-in. titanium investment casting replaced 88 stainless steel parts (from five vendors) that were previously machined and welded together.

* The casting, which supports the front fan section of the engine and ties it to the compressor section, provides improved strength and dimensional control in addition to a 55% weight reduction.

* Conversion to a metal casting allowed GE to include several unique details including bosses, flanges and a 2-in. larger overall diameter.

Cast Component:. An axle housing for a construction skid-steer loader.

Material: 80-55-06 grade ductile iron.

Process: Green sand casting.

Casting Supplier: The Dotson Co., Mankato, Minnesota.

* This 65-lb component was redesigned to a one-piece ductile iron casting from a seven-piece steel weldment.

* The casting design provided a cost savings of $15/part with an annual cost savings to the customer of $120,000.

Cast Component: A laser chassis (housing) for an Israel Aircraft Industries night targeting system.

Material: A357 aluminum alloy.

Process: Investment casting.

Casting Supplier: Howmet Corp., Greenwich, Connecticut.

* Previously machined from A6061 aluminum wrought alloy, the component was redesigned for investment casting at a cost savings of $25,000/part.

* The casting achieves mechanical properties of 41 ksi tensile strength, 31 ksi yield strength and 3% elongation in areas up to 2.5 mm thick, and 38 ksi tensile strength, 28 ksi yield strength and 5% elongation in areas over 2.5 mm thick.

Cast Component:. An automotive wheel spindle knuckle.

Material: Austempered ductile iron (ADI).

Process: Green sand casting.

Austempering Facility: Applied Process, Inc., Livonia, Michigan.

* The one-piece ADI component provided a 40% cost reduction over an aluminum knuckle with a pressed steel spindle and a 10% cost reduction over a forged steel knuckle.

* This one-piece safety critical component was specified to ADI for the material's relative cost per unit of yield strength, improved fatigue strength, enhanced wear resistance and superior noise dampening characteristics in comparison to aluminum.

Cast Component: A brake pedal for the C7 Corvette.

Material: B356 aluminum alloy.

Process: Low-pressure permanent mold casting.

Casting Supplier: Eck Industries, Inc., Manitowac, Wisconsin.

* Converted from a steel fabrication, this structural, safety critical casting achieves 0.5 in. deflection before fracture, ASTM E-155 Frame 2 requirements for shrinkage in critical areas, and exceptional appearance and feature definition, which is mandatory because the pedal face is visible.

* To solve structural and mechanical property concerns, tightly controlled modified alloy chemistries and a modified heat treatment cycle were used with low-pressure permanent mold casting to achieve the mechanical properties of 35 ksi tensile strength, 25 ksi yield strength and 7% elongation.

Cast Component: A yoke for the material handling industry.

Material: C95500 nickel aluminum bronze.

Process: Permanent mold casting.

Casting Supplier: Piad Precision Casting Corp., Greensburg, Pennsylvania.

* Previously machined from cold-rolled steel in four separate pieces and subsequently assembled, welded and painted, this component was redesigned to a single-piece bronze permanent mold casting that doesn't require post-casting processing (with the exception of threading four holes).

* Permanent mold casting allowed the component to achieve high yield strength (75 ksi), and the nickel aluminum bronze alloy promotes good corrosion resistance, which is required in the casting's chlorine gas environment.

Foundries interested in showcasing their castings in the Castings in Action and Casting Innovations departments of Engineered Casting Solutions, please contact Associate Editor Alfred Spada for submission information at 847/824-0181 or email him at [e-mail].