The Study Of Lost Foam Composite Casting Process For Bimetal Bend Pipes

Boom conveying bend pipes are the main wear parts in the boom system of Concretepump trucks. Concrete materials with great speed have large centrifugal force whenpassing the bend pipes, and exaggerate the wear and corrosion of the bend pipes, makingthem the weakest parts in the boom system. However, the traditional casting processcannot meet customers’ increasingly high requirements in service life, so it is important todevelop new technology and improve the quality of casting in practice. And it makes greatsense to the development of construction and concrete pump truck business in china.Based on the LFC and liquid-solid composite casting process, bimetal mechanicalriveting process is used in the trial production of bimetal bend pipes. It’s expected toreduce the bimetal shrinkage distance and improve the service life through improvingbend pipes’ structure such as increasing its inner thickness and arranging the riveted holesreasonably. The sections of bend pipes with different riveted holes are observed and theirbonding areas are compared.Also, LFC” Pouring after Burning and preheating outside” composite process isattempted to alleviate the problems in the bimetal mechanical riveting process such aspoor bonding condition and multiple operation. The structure of the mould and the gatingsystem are improved and the outside of the low-carbon steel pipe is fully preheated byflame in this composite process. The feasibility of LFC” Pouring after Burning andpreheating outside” is explored.In order to reduce the energy loss of flame and high-temperature liquid metal heatdispersion, LFC” Pouring after Burning and preheating inside” composite process is usedin the trial production of bimetal bend pipes. The inside of the low-carbon steel pipe isfully preheated by the flame. The impact of vacuum degree on the bimetallic bondinginterface is explored, and the mechanical properties and microstructure of the bend pipeswith good bimetallic interface made in no vacuum are tested and compared.The actual process conditions are simplified and the approximate simulation methodis used to simulate the above different LFC composite processes to observe their changes in the flow field, temperature field and stress field. Deep analysis is done to explore thereasons for the bimetallic bonding according to the different changes in the fields oftemperature and stress.