Numerical Simulation And Experimental Study On Centrifugal Casting Process Of 40Cr/Q345 Bimetallic Ring

The direct rolling of bimetallic centrifugal ring casting billet to form bimetal ring parts is a short process and brand-new process technology and concept.It saves energy,reduces material waste,improves production efficiency,and is beneficial to environmental protection.This process has high requirements for the quality of the ring blank,and its performance is directly related to the quality of the subsequent rolling part forming.In this paper,the bimetallic ring with the outer layer of 40 Cr and the inner layer of Q345 is the research object.Flow-3D is used to simulate the centrifugal casting process of the bimetallic ring.According to the influence of different process parameters on the forming of the ring blank,the process parameters are optimized.Then the obtained parameters are used for actual casting,and the sampling experiments are carried out to verify the results.The main research content and achievements of this subject are as follows:The filling process of outer metal is simulated,and it is found that the faster the speed,the smaller the pitch and the smaller the eccentricity.The faster the pouring speed,the greater the patterning rate,the more uniform and smooth the surface of casting.When the ratio of the distance between the gate and one end of the tube to the length of the entire tube is 0.4,the molten metal flows in almost two directions at the same time,which speeds up the patterning rate.Increasing the pouring temperature has no obvious effect on the patterning rate of the short tube.The final optimized process parameters for pouring the outer metal layer are:speed 800r/min,pouring speed 5770g/s,pouring temperature 1560?,preheating temperature 250?,and the ratio of the distance between the gate and the end of the tube to the length of the entire tube is 0.4.The filling process simulation of the inner layer of metal found that the cooling temperature of the outer layer of metal and the pouring temperature of the inner layer of molten metal have a great influence on the bonding interface of the bimetallic ring.If the temperature is too low,metallurgical bonding of the interface can not be achieved,resulting in poor bonding effect.If the temperature is too high,a mixed flow phenomenon will occur at the interface,which will lead to dilution of the inner layer material and thinning of the outer layer material,which will affect the quality of the casting.Finally,when the outer layer cooling temperature is 1350°C,the inner layer metal is poured at 1580°C.At this time,the temperature melting zone at the pour point is 6.5mm,and the temperature melting zone at the end point is 4mm.The casting billet is sampled for tensile test,hardness test and microstructure observation.Founding that the hardness of the bonding layer is between 40 Cr and Q345.Observation of the metallographic structure reveal that there is a clear physical boundary between the outer layer of metal and the inner layer of metal,there is no mixed flow phenomenon,and no cracks and pores appear in the transition layer.The tensile experiment found that the final fracture was not in the middle bonding layer,but on the Q345 side,indicating that the bonding layer was well bonded,and that the parameters obtained by the simulation were able to cast a good quality ring blank.Through research,high-quality 40Cr/Q345 bimetal ring blanks were obtained,which laid a good foundation for subsequent direct rolling and forming of 40Cr/Q345 bimetal ring parts.