Mi Guofa et al. of Henan University of Technology simulated flow field, temperature field and stress field of valve body duringby numerical simulation method, predicted possible defects and analyzed the cause of defects.They pointed out that double casting system is very easy to produce casting defects such as air entrainment and cold insulation; when changing the core to hollow, it can increase the concessionality of the core, make the casting shrink freely during solidification, reduce the stress generated by the spherical part of the casting and eliminate casting cracks.
Xiong Chao and others from Institute of Metal Research, Chinese Academy of Sciences studied the casting process of exhaust valve for automotive engine, calculated the temperature field during filling and solidification process by simulation software, predicted and analyzed the causes of defects.Ma Yingchu et al. studied the casting characteristics of vertical centrifugal cast exhaust valve by combining isothermal quenching with metallographic observation in order to solve the casting defects such as cold insulation and insufficient pouring caused by the large exhaust valve in casting, revealed the influence of superheat on the formability and oxygen content of exhaust valve, and thus determined the optimum casting parameters for this valve by this method.Number provides reliable basis for industrialized production.
JonesP.E. et al. studied the metal mold casting of exhaust valve for automobile. They analyzed the life of the casting, the interaction between the casting and the liquid metal, and the formation and control of shrinkage holes. The casting was treated by heat treatment and hot isostatic pressure to eliminate the small voids (pinholes, voids) inside the casting, improve the mechanical properties of the casting, and analyzed the micro-structure and pull-out of the treated casting.Extension, creep and fatigue properties.
Valentan Bogdan et al. studied the application of additive manufacturing technology in grey cast iron valves and put forward how to apply additive manufacturing technology to traditionalprocess. Sand molds are manufactured by selective laser sintering and sand cores are manufactured directly by additives.
Rasador Andr_et al. compared the conventional sand casting process with the vertical centrifugal casting process for alloy steelassemblies in order to prove the possible evolution of material properties and properties, analyzed the micro-structure of the material, performed tensile and hardness tests, and evaluated the integrity of the valve body using ultrasound and radiography.