A Study Of The Combination Forming Technology Of Die Casting And Forging Of A356Aluminum

Combination process of die casting and forging is a integrated forming method. This method production owns a high efficiency and a low cost. The parts made by this method have good mechanical properties comparable to forging parts. A356aluminum is selected as the search object. This paper mainly focus on the influence of process parameters on the morphology, the structure and the mechanical properties of the sample parts, on the basis of which the automobile brake bracket is simulated with the FLOW-3D simulation software. According to the simulation results, the influences of filling speed, the up forging time, the forging pressure and the T6treatment on the structure and properties of automobile brake bracket are studied in detail. Results show that:1) According to the samples findings, the melt filling with too fast speed or too low could not make samples parts have a good morphology and structure. When the melt filling speed is66mm/s, the sample parts could have a good morphology and structure. According to the regularities of influence of process parameters on the samples, the automobile brake bracket is simulated with the FLOW-3D simulation software. It is discovered that the automobile brake bracket own a good feature for castings when the melt filling speed is66mm/s, which is consistent with simulation results.2) It is found that no matter whether the sample parts and the automobile brake bracket (casting and forging parts) could have a strengthening effect both on the surface and the center. Due to a large degree of super-cooling and rapid solidification for the surface of casting and forging parts, the grains are so small that the surface owns a fine grain strengthening. In the center mental of casting and forging parts, the temperature is high, and the deformation recitation is smaller so that the plastic deformation reaches the purpose of strain strengthening.3) As soon as up forging time too is short, the casting and forging parts could not reach the purpose of feeding. As soon as up forging time is too long, the forging pressure make the casting and forging parts easy to appear forging crack. When the forging pressure is too low with a relatively small deformation, the strengthening effect is not obviously, in contrast, when the forging pressure is too high, the parts are easy to appear forging crack.4) When the melt filling temperature is725℃, the filling speed is66mm/s, the up forging time is6s, the forging pressure is90MPa, the sample parts could have a good morphology, structure and comprehensive mechanical property. After T6treatment, vickers hardness, tensile strength and elongation of sample parts are98HV,340MPa,16.7%respectively. When the melt filling temperature is725℃, the filling speed is66mm/s, the up forging time is3s, the forging pressure is270MPa, the automobile brake bracket could have a good morphology, structure and good comprehensive mechanical property. After T6treatment, rockwell hardness, tensile strength and elongation of the automobile brake bracket are58HRB,335MPa,18.4%respectively.50figures,11tables,89references.