Lost foam casting is abbreviated as LCP. This process is known as “new casting technology representing the 21st century” and “green engineering of casting” for its three characteristics of accurate forming, clean production and providing sufficient freedom for casting structure design. Lost foam casting obtains the foam model similar to the size and shape of the casting through numerical control processing or molding. After bonding and assembling the riser system, it is brushed with fire-resistant coating and dried to make it have sufficient strength. The molding is completed by combining sand dropping and vibration. The original foam pattern is gasified when encountering high-temperature liquid metal under vacuum and negative pressure, Its volume is occupied by liquid metal, and the casting is formed after solidification and cooling.
According to the actual production situation and relevant discussion of domestic wear-resistant parts manufacturing enterprises, resin sand or sodium silicate sand casting method is generally used for castings with high strength and wear resistance requirements. There are many disputes in the industry that lost foam casting technology is used to produce wear-resistant parts. It is considered that the thermal conductivity of lost foam casting dry sand mold is small, Slow heat dissipation will lead to coarse grains, which will reduce the mechanical properties and service life of wear-resistant castings. However, compared with the traditional casting method, the lost foam casting process is very suitable for mass production due to its simple modeling and easy automation. At present, ZHY casting adopts the lost foam casting method to produce wear-resistant castings and achieves good results:
ZHY casting produces wear-resistant alloy cast steel spiral stirring blade, squirrel cage crusher rotor and arc-shaped wear-resistant shoe plate, high chromium cast iron wear-resistant spiral blade, blast furnace wall lining plate and wear-resistant grinding plate, wear-resistant alloy pear thorn plate, chromium town alloy brick making machine high chromium reamer and wear-resistant and heat-resistant composite conical grid plate, and lost foam casting company produces bulldozer teeth and gear sleeve Production of extra large shovel teeth for excavators, crawler shoes for mining down the hole drills, and crawler shoes for tanks.
At present, there are few reports on the research of bimetallic liquid lost foam casting composite casting process. Yuewenjia et al. Applied the lost foam composite casting process to the manufacturing of dual material automobile stamping dies. The punch and die seat structure of stamping dies were poured separately by using the dual pouring system. The the first mock examination two material automobile stamping die products were obtained, in which the punch part was made of nodular cast iron and the die seat part was made of gray cast iron. This process solves the problems of material cost waste caused by the use of ductile iron in all molds, and the mold design problems that need to be processed and assembled in the later stage of the separate manufacturing of punch and die base. Observe the appearance quality of the castings after cleaning. The joint surface of nodular cast iron and gray cast iron is smooth and flat, and the joint surface is firm, which meets the use requirements. The properties of the attached cast test bar of the two parts of the casting are tested, and its microstructure meets the requirements. The processing verification of the test product shows that its processing performance is good, and there is no macro separation layer on the joint surface of the two materials after secondary processing. Wufuyou’s invention patent adopts the method of lost foam casting the hammer head of bimetallic double solution composite crusher. Compared with the original vertical pouring process of blowing carbon dioxide and resin sand with hard sand mold sodium silicate sand, this invention has the advantages of simple process, stable quality, double production efficiency, and the basic structure of the joint part of the two materials is the natural transition of metal, The high wear-resistant and high chromium cast iron required by the working part of the workpiece and the high toughness cast steel required by the non working part are cast into one, which saves precious metal materials and improves the service life. The Bimetal Hammer produced by the dual liquid lost foam casting process is tested on 10kg-100kg products respectively, After repeated use, there is no fracture from the composite part.