Stainless Steel Casting of Valve Components

Stainless steel valve components refers to valves parts made of stainless steel. Stainless steel valves are widely used in chemical, petrochemical, petroleum, paper, mining, power, liquefied gas, food, pharmaceutical, water supply and drainage, municipal, mechanical equipment supporting, electronic industry, urban construction and other fields. The valve is the control part in the pipeline fluid conveying system, it is used to change the path section and the flow direction of the medium, has the function of diversion, cut-off, adjustment, throttling, check, shunt or overflow pressure relief. Valves for fluid control range from the simplest globe valves to the most complex automation systems. Stainless steel valve can be used to control the flow of water, steam, oil, gas, mud, all kinds of corrosive media, liquid metal and radioactive fluid and other types of fluid, valve working pressure can be from 0.0013MPa to 1000MPa of ultra-high pressure, operating temperature from -269℃ ultra-low temperature to 1430℃ high temperature.

Stainless steel has characteristics of corrosion-resisting, toughness and weldability. The valve components that makes with stainless steel will be strong sturdiness and not easy rusting. Besides, the price of stainless steel is affordable, so main valve components are mainly produced by stainless steel investment casting.

Stainless Steel Types for Valve Casting Components

  • 304 stainless steel: 18% chromium and 8% nickel, commonly known as 18-8 stainless steel. This type of stainless steel contains Nickel element, which can creat valve components with good corrosion resistance
  • 410 stainless steel: Contain 13% chromium, less than 0.15% carbon and a small amount of other elements. But do not contain nickel, corrosion resistance is relatively poor.
  • 430 stainless steel: Contain 16%~18% chromium, low carbon content and do not contain nickel element, so the price is low.
  • Hardened stainless steel: In addition to chromium and nickel, it also contains hardened elements such as copper, aluminum and titanium, which can harden the material and increase the strength of valve components.
  • Duplex stainless steel: Typical grade is 2205, namely contain 22% chromium and 5% nickel.

Main Valve Components By Stainless Steel Casting

  • Valve body: The main valve component that is connected directly to piping and controlls media flow.
  • Valve disc: A critical part in butterfly valve.
  • Valve bonnet: The valve component connected to the valve body and forming the pressure chamber with the valve body.
  • Valve Handwheel: The common valve component used to override the control system and to operate the valve manually.

Stainless Steel Casting Process for Valve Components

  • Pattern creation – The wax patterns are typically injection molded into an aluminum die and are formed as one piece. Ceramic cores may be used to form any internal features on the pattern. Several of these patterns are attached to a central wax gating system (sprue, runners, and risers) to form a tree-like assembly. The gating system forms the channels through which the molten metal will flow to the mold cavity.
  • Mold creation – This “pattern tree” is dipped into a slurry of fine-fused, silica, ceramic particles, coated with more coarse particles, and then dried to form a ceramic shell around the patterns and gating system. This process is repeated until the shell is thick enough to withstand the molten metal it will encounter. The shell is then placed into an autoclave and the wax is melted out leaving a hollow ceramic shell that acts as a one-piece mold, hence the name “lost wax” casting.
  • Pouring – The mold is preheated in a furnace to approximately 1800°F – 2000°F and the molten metal is poured from a ladle into the gating system of the mold, filling the mold cavity. Pouring is typically achieved manually under the force of gravity, but other methods such as vacuum or pressure are sometimes used.
  • Cooling – After the mold has been filled, the molten metal is allowed to cool and solidify into the shape of the final casting. Cooling time depends on the thickness of the part, thickness of the mold, and the material used.
  • Casting removal – After the molten metal has cooled, the mold can be broken and the casting removed. The ceramic mold is typically removed using pneumatic vibration water jets, but several other methods also exist. Once removed, the parts are separated from the gating system by either sawing or cold breaking (using liquid nitrogen) in some cases.
  • Finishing – Often times, finishing operations such as grinding or sandblasting are used to smooth the part at the gates. Heat treatment is also sometimes used to harden the final part.

CFS Stainless Steel Foundry can customize valve components in different stainless steel grades. With value added services like heat treatment, machining, etc, we are able to supply finished valve components for our customers. Currently, we main export cast stainless steel components to companies from USA, UK, Canada, Australia, South Africa, etc. Any inquiry on stainless steel casting of valve components, pls feel free to send us the drawing or sample for quoting!