Wuxi Dongao Nonferrous Casting Co., Ltd.
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Casting Process Design Of High Temperature And High Pressure Valve Castings
- Jul 03, 2017 -

(1) Determination of casting shrinkage. The castings used in the CF8C material is austenitic stainless steel, in the case of contraction shrinkage, combined with the shape of the casting structure, casting outer cavity scale with 2.0%, 1.5% of the inner scale.

(2) sub-surface selection. The valve requires the center line of the pipeline in the same plane, the annular pipe filling more difficult, so the center of the three nozzles for the sub-surface, the casting is divided into upper and lower halves.

The choice of sub-surface through the valve castings the center of the nozzle, so that the plane of the plane is the largest section of the valve castings to ensure that the valve castings pipe axial center line in the same plane to reduce the use of casting sand core, Reducing the deviation of the assembly of the core under the box, to avoid the formation of puff after pouring, improve the valve parts of the relative size of the dimensional accuracy and surface quality, shape more convenient and simple.

Valve castings process structure diagram

(3) pouring system design. The valve castings system uses a bottom pouring system. The pour point system is basically submerged in the submerged state, filling the smooth, can avoid the molten metal sparks, oxidation and the resulting casting defects; no matter how much the gate ratio, the basic work of the runner In the full state, favorable slag, the cavity of the gas easily discharged in order.

CF8C material alloying element Cr content is higher. Cr high melting point, so that the liquid steel liquidus temperature rise, reduce the flow of molten steel, pouring process prone to cold, surface wrinkles and so on. Cr is easily oxidized in the molten steel to form a chromium oxide film, which is prone to oxidative inclusions when it is filled. Pouring system settings should take full account of the above factors to ensure that filling fast and smooth.