Advantages & process of Investment casting

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Features of Investment Casting Process For Valve
Components
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• There are many types of valves such as butterfly
  valves, gate valves, check valves, ball valves,
  control valves and many more which are used in
  industrial and domestic piping applications. The
  components of valves such as body, bonnet, flange
  and disc are manufactured using casting process.
  Almost all metals can be casted into valve
  components. Stainless steel, carbon steel and
  other carbon alloys are also widely casted into
  valve components. There are many types of casting
  process. Here we will discuss about Lost Wax or
  investments castings for valves. Investment
  casting produces intricate valve components
  accurately. The valve components produced by
  investment casting have precise dimensions and
  are very sturdy. Energy expended and material
  waste generated by investment casting process are
  also low. These are the reasons why foundries are
  mainly using investment casting for valve
  components.

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Process of Investment Casting

• In the very first step, patterns are created
  using a metal injection die. The design of the
  patterns created are same as the patterns
  required on the final component. However, thermal
  shrinkage is also taken into account when
  creating patterns. The patterns are made of
  molten wax injected into the metal die. Complex
  patterns can be created by joining multiple wax
  patterns using adhesive.
• The wax patterns are assembled together to form a
  gate and runner metal delivery system called
  tree. Many wax patterns can make up a single tree
  depending upon the size and configuration of the
  valve component being casted.

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• In order to create the mould shell, the wax
  pattern is dipped in a ceramic slurry. The slurry
  coats the wax. Thereafter, it is covered with a
  sand stucco and left to dry. The process of
  dipping in slurry and drying using sand stucco is
  repeated multiple times till the mould shell
  acquires the required thickness and strength as
  per the dimensions of the final component to be
  casted.
• The ceramic coated shell or tree is then put in
  an autoclave and heated up to 200 degrees to melt
  the wax. When the wax has melted away completely,
  the temperature is increased to 900 degrees to
  impart strength to the mould. The mould is in the
  shape of the component and has a cavity.

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• Molten metal is poured in the mould which is
  preheated. The molten metal must be at the
  correct temperature for proper solidification.
  The velocity of the pour must also be accurate to
  prevent pattern damage and formation of gas
  bubbles. There are software tools available to
  ensure that the pouring and cooling process takes
  place in complete accordance with the various
  required parameters as per the specific metal or
  alloy used.
• Once the molten metal solidifies and cools to
  form a cast, the mould is broken in a process
  called knockout. The cast is then subjected to
  machining, grinding and sandblasting. Dimensional
  and other inspections are done before packing.

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Advantages of Investment Casting

• Investments castings for valves produces
  components in a plethora of sizes and weights.
  Multiple components can be turned into a single
  component using investment casting because highly
  intricate designs and shapes are possible using
  this process. The components have highly smooth
  surfaces. Thus, investment casting is an
  manufacturing procedure developed on the lost-wax
  casting, one of the firstborn method called as
  metal-forming procedures. The products of
  Investment Castings are useful for various
  industrial usages like water, oil, gas, steam,
  nitric acid, and acetic acid. A few clients
  expect to give projecting, yet in addition expect
  us to offer handled or surface treatment. The
  parts offered not just address the client's
  issues simultaneously, yet in addition the
  quality is profoundly trusted by the clients.
  Subsequently, the extent of completed items is
  expanding.

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