Special Steel Castings

Brian MitchellChris Guth

Trevor SeaseAndrew MacMillan

Whiskey Tango Foxtrot

Firearms Investment CastingComponents of firearms are cast using the investment casting process.2

Investment casting is done using disposable shells made of sand and a fine ceramic liquid slurry.1

Molds are made around a wax pattern which can be made and remade to precise specifications provided by the engineer.1

Molten steel is cast into the ceramic shells and then heat treated to improve physical properties of the steel.1

Properties of steel components are then tested using non-destructive procedures.2

Properties must fit MIL DOD standards.2

1. "Investment Casting." YouTube. Web. 28 Nov 2010. <http://www.youtube.com/watch?v=DKLna0J6YTU&feature=related>.

2. "Firearms." Milwaukee Precision Casting - Military & Commercial Firearms Components. Web. 28 Nov 2010. <http://www.milwaukeeprec.com/military-and-firearms.htm>.

Stainless Steel Investment Casting• Corrosion and abrasion resistant• No plating necessary• One of the most popular investment

casting materials• Fills sand mold very well leaving

minimal voids.• Produces very little waste reducing

cost• Mechanical properties similar to steel

are attainable

http://www.cypressindustrial.com/stainless_steel_investment_castings.html

http://www.conexmetals.com/stainless_steel_lost_wax_investment_casting_castings/stainless_steel_lost_wax_investment_casting_castings/stainless_steel_lost_wax_investment_casting_castings.htm

High Pressure Die Casting• Molten metal is injected into a steel mold

under high pressure• Provides a more accurately dimensioned,

uniform part• Secondary machining can sometimes be

avoided, making the process cheaper than conventional casting

• Products formed from die casting are 100% recyclable

• Complex shapes can be achieved easier than with other mass production techniques

• Two processes used for high pressure die casting– Hot Chamber shot system– Cold Chamber shot system

http://strohdiecasting.com/manufacturing/high-pressure-die-casting/

Permanent Mold Casting• Permanent mold casting is metal casting process that

employs reusable molds• Molds for the casting process consist of two halves.• Casting molds are formed from gray cast iron because

of its thermal fatigue resistance• Process begins with preheating the mold, then spraying

mold with mold wash • Molten metal is then poured in mold, then removed

after solidification • Four different types permanent mold casting that

include: Vacuum, low pressure, gravity, and slush • Advantages include: reusable mold, good surface finish,

and good dimensional accuracy• Disadvantages include: high tooling cost, limited to low-

melting-point metals, and short mold lifehttp://www.custompartnet.com/wu/permanent-mold-castingDegarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003), Materials and Processes in Kalpakjian, Serope; Schmid, Steven (2006), Manufacturing Engineering and Technology (5th ed.), Pearsonanufacturing (9th ed.), Wiley,

GO COCKS.