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PRODUCT INNOVATIONS


Quality Castings Improves Melt Quality With SPAL Argon Shielding When Richard Adams became


general manager of Quality Castings, Waukesha, Wis., in 2007, he real- ized the investment casting facility was sending too much metal out for scrap recycling. He installed a device designed to dispense argon on top of the melt to prevent oxidation and avoid the introduction of moisture. While the in-house-fabricated system helped improve quality, crucible life and rework, after Adams and Randy Harrington purchased Quality Cast- ings in 2010, they believed more material, time and energy savings could be achieved by processing even cleaner molten metal through its melting and casting operation. When Adams first began introduc-


ing argon to the induction melting process at Quality Castings in 2008 with the in-house system, he helped his company double crucible life, reduce welding rework by 50%, and re-use revert three times, thus saving his company $0.65/lb. for alloy refin- ing. Still, Air Liquide noticed Quality Castings was losing 50% of its argon through an inconsistent delivery system. Plus, the in-house designed system occupied floor space that obstructed lean manufacturing flow. Quality Castings, which pours cast-


ings from fractions of an ounce to 60 lbs., invited Air Liquide, Houston, Texas, to implement its SPAL argon shielding technology on one of its 300-


Quality Castings receives a supply of argon from a permanently installed bulk tank (right) by means of a vacuum jacketed pipe system.


lb. capacity induction melting furnaces for 316 and 15-5 stainless steel alloys. An Air Liquide application specialist evaluated the induction furnace and determined the optimum cryogenic liquid argon flow rate. He also pro- vided safety talks prior to the initial test, onsite training, engineering and troubleshooting. The mechanics of the SPAL process


at the investment casting facility include a supply of argon from a permanently installed bulk tank. The cryogenic argon is conducted from the bulk tank to the induction furnace area by a vacuum jacketed pipe system. The SPAL process was designed to


Table 1. Effect of Clean Molten Metal Processing on Total Operational Cost Item


Melting alloy yield increase/cycle Fused silica crucible life increase Silicon-titanium de-oxidation additions


Scrap reduction due to porosity and inclusions Rework reduction (welding)


Melt temperature decrease (304 stainless steel) Tap-to-tap time (304 stainless steel) Revert re-use (alloy fade and purity)


Cut-off saws and grinding belts life increases VGL/dewar vs. bulk delivery of argon savings Machinability/tool life


MODERN CASTING / January 2011


With In-House System 2%


100% 9 oz. 5%


50% n/a n/a


3 times 20%


$8,000/month n/a


reduce the interaction between molten metal and atmospheric gases, such as oxygen and hydrogen, during air melting operations. The liquid argon evaporates on or near the surface of the molten metal, expands 840 times in volume and displaces the air, thus purging the furnace atmosphere. After four months in operation, the


With SPAL 4%


160%


4 oz. (55%) 10% 75% 150F 10%


100% 40%


$3,000/month 10 times


SPAL process at Quality Castings further improved crucible life by another 30%, reduced silicon-titanium deoxidation material by 55% and led to a 25% reduc- tion in welding rework due to improved surface finish. The company performing machining for Quality Castings reported tool life increased 10 times. Further comparison of the impact of


processing clean molten metal on total operational cost at Quality Castings is shown in Table 1. The investment casting facility calculates the improved delivery system from Air Liquide led to $5,000 per month in argon savings. MC Visit www.us.airliquide.com for more information.


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