Metal casting

• US 3,863,706 A
• Filed: 12/04/1972
• Issued: 02/04/1975
• Est. Priority Date: 12/04/1972
• Status: Expired due to Term

• Current Assignee: George D. Chandley, John N. Lamb
• Original Assignee: George D. Chandley, John N. Lamb
• Inventors: Chandley, George D., Lamb, John N.
• Primary Examiner(s): Husar, Francis S.
• Assistant Examiner(s): Rising, V. K.
• Application Number:
  US05/312,138
• Time in Patent Office: 792 Days
• Field of Search: 164/306,309,61,62,257,262,77,63,65,119,63,361,129,363,257,256,337,135,136,253
• US Class Current: 164/255
• CPC Class Codes: B22D 18/06 Vacuum casting, i.e. making use of vacuum to fill the mould

Abstract

Apparatus, methods and molds for casting metal in an evacuatedinert gas atmosphere. The apparatus comprises a sealable melting and mold pouring chamber having a sealable loading compartment mounted thereon with a conduit having a valve communicating therebetween and a sealable mold container having a bottom opening for sealing around the lower open end of a gas permeable refractory shell mold sealingly supported therewithin and extending downwardly therebeyond. Power means supports the container from above for movement between the chamber and compartment through the conduit to a melting crucible within the chamber directly beneath the container. The mold is loaded and unloaded with the container in raised position within the compartment while maintaining the chamber in evacuated condition by closure of the valve. A movable drip guard is mounted within the loading compartment between the valve and the container in its raised position. The refractory, gas permeable, shell mold preferred has a lower open end with a central vertical riser passage and may have a plurality of overlapping mold cavities clustered thereabout connected to the riser passage by gate passages. The cross section area dimension of the riser passage is at least one inch and five times as great as the cross section area dimension of a gate passage, so that molten metal can be drained from the riser passage to provide discrete unconnected cast parts from a single mold after the mold is separated from them.

Claims

1. In casting apparatus having a sealable melting and mold pouring chamber, a sealable loading compartment mounted on said chamber and valve and conduit means communicating between said chamber and said compartment that improvement comprising:

a sealable mold container having a bottom opening for sealing around the lower open end of a gas permeable mold supported therewithin and extending downwardly therebeyond said mold container including upper and lower cup elements movable into sealed relationship with one another a crucible in said chamber having surrounding induction coils for holding and stirring molten metal to cause outward surface movement thereof along its surface to carry impurities away from the central area of said crucible power means including piston means independently supporting said cup elements from above for relative movement into said sealed relationship and for movement between said compartment and said chamber through said valve and conduit means to said central area of said crucible and means for selectively varying the pressure of said chamber, compartment and container to fill said mold after lowering said container with the lower open of said mold beneath the surface of molten metal in said central area of said crucible and permit loading and unloading said mold from said container in raised position by relative movement of said cup elements within said compartment while maintaining the chamber pressure by closure of said valve and conduit means.

2. Casting apparatus as claimed in claim 1 further comprising a movable drip guard mounted within said loading compartment between said valve and conduit means and said cup elements in raised and separated position.

3. In casting apparatus having a sealable melting and mold pouring chamber, a sealable loading compartment mounted on said chamber and valve and conduit means communicating between said chamber and said compartment that improvement comprising:

a sealable mold container having a bottom opening for sealing around the lower open end of a gas permeable mold supported therewithin and extending downwardly therebeyond said mold container including upper and lower cup elements movable into sealed relationship with one another power means for supporting said elements for relative movement into said sealed relationship and for moving said container between said chamber and said compartment through said valve and conduit means a melting crucible for holding molten metal mounted within said chamber beneath said container and means for selectively varying the pressure of said chamber, compartment and container to fill said mold after lowering said container with the lower open end of said mold beneath the surface of molten metal in said crucible and to permit loading and unloading said mold from said container in raised position within said compartment while maintaining the chamber pressure by closure of said valve and conduit means.

4. Casting apparatus as claimed in claim 3 further comprising a movable drip guard mounted within said loading compartment between said valve and conduit means and said container in raised position.

5. Casting apparatus as claimed in claim 3 wherein said power means are fluid piston means independently supporting said cup elements.

6. Casting apparatus comprising a melting crucible having surrounding induction coils for holding molten metal a sealable mold container having a bottom opening for sealing around the lower open end of a gas permeable mold supported therewithin and extending downwardly therebeyond, said mold container including upper and lower cup elements movable into sealed relaTionship with one another power means including piston means independently supporting said cup elements from above for relative movement into said sealed relationship and for movement towards said crucible to lower the open end of said mold beneath the surface of molten metal in said crucible and means for relatively varying the pressure within said container to fill said mold after lowering said container with the lower open of said mold beneath the surface of molten metal in said central area of said crucible and permit loading and unloading said mold from said container in raised position by relative movement of said cup elements.