Method of pouring and cleaning of castings

  • Commonly used pouring methods in investment casting are:
    1) There are the following types of thermal gravity casting methods.
    This is the most widely used form of casting, that is, after the shell is removed from the roaster, it is cast at high temperature. At this time, the metal cools slowly in the mold shell, and the mold can be filled with high fluidity, so the casting can well replicate the shape of the cavity and improve the accuracy of the casting. However, the slow cooling of the casting in the hot mold will cause coarse grains, which reduces the mechanical properties of the casting. When casting carbon steel castings, the surface of the casting that cools more slowly is also prone to oxidation and decarburization, which reduces the surface hardness, finish and dimensional accuracy of the casting.invest-casting.com Precision Investment Castings China prototype company service include : High Quality Investment Casting Parts Custom,Lost Wax Investment Casting, Sand Casting,Lost Foam Casting,Gravity Casting,Die Casting,Graphite Casting ,Casting Moldsmanufacturers.
    2) Vacuum suction casting
    Put the mold shell in the vacuum casting box, and suck the gas in the mold cavity through the tiny pores in the mold shell, so that the liquid metal can better fill the mold cavity, copy the shape of the mold cavity, improve the casting accuracy, prevent pores, pouring Insufficient defects. This law has been applied abroad.
    3) Crystallization under pressure
    Put the shell in the pressure tank for pouring. After the end, the pressure tank is closed immediately, and high-pressure air or inert gas is introduced into the tank to solidify the casting under pressure to increase the density of the casting. The maximum pressure abroad has reached 150atm.
    4) Directional crystallization (directional solidification)
    Some investment castings such as turbine blades, magnetic steel, etc., if their crystalline structure is columnar crystals arranged in a certain direction, their working performance can be greatly improved, so the directional crystallization technology of investment casting is rapidly developed.
    Casting cleaning
    The main contents of investment casting cleaning are as follows:
    (1) Remove the mold shell from the casting;
    (2) Remove the casting from the pouring system;
    (3) Remove the shell refractory adhering to the casting;
    (4) Cleaning after heat treatment of castings, such as descaling, edge and cutting gate residues, etc.invest-casting.com Metal Casting Material include : Stainless Steel CastingAluminum CastingIron CastingBrass CastingTitanium CastingSteel Casting

    The task of investment casting process design is
    (1) Analyze the manufacturability of the casting structure;
    (2) Select a reasonable process plan, determine the relevant casting process parameters, and draw the casting diagram on the basis of the above;
    (3) Design the pouring system and determine the module structure.
    It should be noted here that when considering the above three aspects, the main basis is still the basic principles of the general casting process, especially when determining the process plan and process parameters (such as casting fillet, machining allowance, process ribs, etc.) , except that the specific data is slightly different due to the technological characteristics of investment casting, the design principle is exactly the same as that of sand casting.
    The task and importance of investment casting process design
    Investment casting is a casting process with less or no cutting. It was also called lost wax casting in the past. Because the castings produced by the investment casting process are better than other casting methods in terms of dimensional accuracy and surface quality In addition, the investment casting method can complete the production of some complex and difficult to process castings, so it is deeply loved by enterprises.
    Regarding the investment casting process, the investment casting process design is one of the most important links in the entire investment casting process. This link has a large technical difficulty factor and plays a very important role in the entire investment casting process. This link is mostly due to some professional and technical people.
    Like other casting process designs, the design tasks of the investment casting process are: a. According to specific requirements, analyze the craftsmanship of the casting structure; b. Plan a reasonable process plan, determine the relevant casting process parameters, and draw the casting diagram on this basis. ;c. Design the pouring system and determine the module structure. Except for the specific data due to the slightly different process characteristics of investment casting, the design principle is exactly the same as that of sand casting.
    Since the investment casting process design link is of great significance to the entire casting process, and this link has very high requirements on the quality of the designers themselves, enterprises should pay considerable attention to this link.

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