Lost foam casting process of bimetal wear-resistant castings

Lost foam casting 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 the structural design of wear-resistant castings. After lost foam casting, the foam model similar to the size and shape of the wear-resistant castings is obtained through NC machining or molding. After bonding and combining the riser system, the refractory coating is brushed and dried to make it have enough strength. The sand and vibration are combined to form the shape, and the injection is carried out under the suction air pressure. The original foam pattern is gasified by high temperature molten metal, and its volume is occupied by liquid metal, and then it is solidified and cooled to form wear-resistant castings.

According to the actual production situation of domestic wear-resistant parts manufacturing enterprises and relevant literature discussion, resin sand or sodium silicate sand casting method is generally used for wear-resistant 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 because of its simple shape and easy automation. At present, many enterprises in China use the lost foam casting method to produce wear-resistant castings, Good results have been achieved: Wuhan Hengchang special steel casting plant produces wear-resistant alloy cast steel spiral stirring blades, squirrel cage crusher rotors and arc-shaped wear-resistant shoe plates, and Wuxi Yongjin Solid Casting Co., Ltd. produces high complex cast iron wear-resistant spiral blades, blast furnace wall lining plates and wear-resistant grinding plates, Inner Mongolia Chifeng Fuzi Technology Service Co., Ltd. produces wear-resistant alloy pear thorn plate, Wuxi zhidefu lost foam casting Studio produces chromium town alloy brick making machine high chromium reamer and wear-resistant and heat-resistant composite conical grid plate, and Beijing tianzhe lost foam casting company produces bulldozer teeth and gear sleeve Sichuan Panzhihua mining company produces extra large shovel teeth of excavators and crawler shoes of mining down the hole drill, and Xiangtan Jianglu machinery factory produces tank crawler shoes.

At present, there are few reports on the research of bimetallic liquid lost foam casting composite casting process. Yue Wenjia and the first mock exam were applied to the manufacture of double material automotive stamping dies. The double winding system was used to separate the punch die from the die base structure. The die part was made of ductile iron, and the mould part was gray cast iron material with a two material steam car stamping die product. This process solves the problems of material cost waste caused by the use of nodular cast iron in all molds and the design of molds that need to be processed and assembled in the later stage of split manufacturing of punch and die base. Observe the appearance quality of wear-resistant 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 wear-resistant casting were tested, and its microstructure met 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. Wu Fuyou’s invention patent adopts the method of lost foam casting the hammer head of bimetallic double solution composite crusher. Compared with the original hard sand sodium silicate sand blowing carbon dioxide and resin sand flat vertical winding process, the invention has the advantages of simple process, stable quality and doubled production efficiency, The basic structure of the joint part of the two materials is the natural transition of metal, which makes the high wear-resistant and high chromium cast iron required by the working part of the workpiece and the high bremsstrahlung cast steel required by the non working part cast into one, saving precious metal materials and improving the service life at the same time, The bimetallic hammer produced by double liquid lost foam casting process was tested on heavy products respectively. After repeated use, there was no fracture from the composite part.

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