Application of coatings in epc castings
Effect of epc casting coating on epc forging
The effect of the die coating is to support and protect the foam mold, avoid liquid metal penetration sand and sticky sand, receive differentiated products and allow differentiated gas to pass through the coating, connect the foam mold volatilized formed cavity complete, and connect the liquid metal heat will not be soon spread.Therefore, the use of die casting coating can reduce the general roughness of die casting, ensure casting accuracy, reduce or avoid casting sand, sand hole, hole, metal infiltration, cold insulation, pouring, carbon deposition and other shortcomings.In order to die die coating should have enough fire resistance, inevitable machine strength, appropriate heat preservation and thermal conductivity function, suitable air permeability and receive liquid differentiation product ability, greasy general situation, adequate brush function, not with foam mold produced chemical reaction.
Die forging coating function analysis
Making coating die forging is avoid casting machine adhering sand and thermal chemical adhering sand, foam mold stiffness, deformation, avoid buried type to facilitate die shape of agile exclude functions such as hot gases differentiation, then why die die forging coating convergence of how the function of Ruth, we will from six aspects to analyze the above.
Die forging coating has these six characteristics (1) high strength and stiffness, to avoid appearance deformation and dry sand damage;(2) high refractoriness, avoid the general situation of casting sticky sand;(3) excellent air permeability, able to quickly export gasified products;(4) strong additional effort, to avoid the production process coating cracking and even off;(5) excellent coating, can be used to facilitate the coating of a certain thickness;(6) excellent sintering and peeling, that is, after casting, the formation of active peeling coating shell, so as to obtain a general situation of bright casting.Five refractory materials commonly used in die forging coatings
With the die forging increasingly growing, people to die forging coatings are increasingly facing.It is reported that refractory materials are dying mold coating aggregate components, refractory materials of many kinds, usually choose the following five:
A.The main components of zirconium powder are ZrO2, SiO2, namely zirconium orthosilicate.It has high fire resistance and is the best anti - clay material for die forging.Casting steel and large cast iron when the use of this kind of refractory materials, can reduce the amount of casting liquidation, the general situation of the bright casting.
B.The primary ingredient of quartz powder is SiO2.Because quartz powder in the premise of different temperature has different crystal shape change, so that its volume changes, and thus reduce its use cost.It is commonly used to cast cast iron, aluminum, copper and other nonferrous metals.Because die forging is primarily used for small and medium pieces, quartz powder is widely used.
C.Alumina alumina is corundum powder, the primary ingredient is Al2O3.It is also a well-functioning refractory material used for pouring steel castings and large castings.
D.Graphite powder graphite powder is one of the commonly affected refractory materials in the production of cast iron.Its thermal shrinkage coefficient is very low, usually within 50×10-7.
E：.Bluestone bluestone has a fire resistance of more than 1800 ° c, and the bluestone is gradually transformed into mullite at 1100-1450 ° c at high temperature. Mullite remains unchanged at 1800 ° c, and it is differentiated into corundum at 1810 ° c.Bluestone price is relatively expensive, is to replace the ideal jade material mineral.