Research On The Precise Blank Forming Worm Wheel Of The High Aluminium Zinc Based Za27 Alloy By The Liquid Forging And Semi-solid Forging Technology

In this thesis, ZA27 alloy was elected,and the precise blank forming of ZA27 wheel worm by Liquid forging and semi-solid forging technology was studied. Mechanical property of semi-solid slurry prepared by electromagnetism stirring under different processing parameter is stated, and optimizing preparation parameter of semi-solid slurry and discussing nonarborescent crystal organization influence under different processing parameter and its formative mechanics; Forming parameter of forging wheel worm by semi-solid slurry is studied,comparing different processing parameter influence on microstructure and forming property and discussing deforming mechanics of forming wheel worm under different forming parameter;Frictional wear of test sample of ZA27 alloy wheel worm prepared by different technology is analysed respectively, and studing the relations of wear property, wear mechanics and forming technology. The result indicate:when semi-solid slurry was prepared by electromagnetism stirring,with the stirring current enlarging,slurry microstructure grain was smaller and more compact and mechanical property was excellent. Stirring time is commonly 10 minute or so, which is not enough to form circinal crystal organization, if the stirring time is too short or too long. The forming property and quality of parts made by liquid forging and semi-solid forging technology have something to do with these factors as following: die preheating temperature,die lubrication, up-down die gap, pressure, given time, dwell time and so on. Part external appearance qulity and microstrure feature as well as mechanical property are bound up with semi-solid slurry preparation. Through comparison experiment of mechanical property and frictional wear of testing sample of blank wheel worm formed by different forging technology,The result indicadted: The hardness of ZA27 alloy wheel worm adopted by sand casting is the lowest, and normal metal casting is second,which is 103.67HB.The hardness of part formed by direct casting after electromagnetic stirring is 18.6% higher than part formed by normal metal casting,and the hardness of part formed by liquid forging technology is 9.5% higher than the hardness of part formed by direct casting after electromagnetic stirring, and the hardness of ZA27 alloy wheel worm formed by semi-solid forging technology is the highest, which is 27.67% higher than the part formed by normal metal casting.Through the wear experiments, the conclusions are as following: 1) The load is bigger and the wearing capacity is bigger; 2) Under low load, the wearing capacity of ZA27 alloy raise gently; 3) When the load is increased,the wearing capacity of different samples raise sharply, and the wear weight loss of ZA27 alloy formed by semi-solid forging is generally lower. These indicate: the ZA27 allloy parts formed by semi-solid forging technology have predominant wear property.