The paper describes an innovative technological solution for producing balls from scrap rail heads. The proposed method consists in performing the following operations: the side pressing of a rail head to increase shape compactness, a process for forming a cylindrical rod by cross-wedge rolling (CWR), a CWR process for producing balls that have a diameter which is by 35% larger than that of the billet, quenching of the produced balls. Tools for the above manufacturing operations are designed, and numerical simulations are performed to verify whether the assumptions of the proposed technique are correct. A flat-wedge reversing mill is designed and constructed that enables performing the two abovementioned rolling operations without idle running, which makes the design innovative on a global scale. The implementation of the proposed method would enable producing balls for grinding media used in ball mills.

In this paper, simulation of the casting and heat treatment processes of front spindle of a rigid dump truck are presented. The objectives are to present how the different operations can be simulated in order to predict the local phases in the different areas of the part. To reach these objectives, two software packages are used in sequenced. The first one, Thercast, is used to simulate the casting operation. The second one, Forge, is applied to the water-quenching simulation. The general formulations used are shortly presented in this paper. The aim of casting simulation is to compute the metal behavior from the liquid state at the pouring stage to the solid state during cooling into the mold. Filling and cooling phases simulations, taking into account the air gap, ensure that no internal defects like shrinkage, porosity, micro porosity or hot tearing are taking place into the part. Forge software allows the water quenching stage simulation. A model is used to deduct the IT diagram (Isothermal Transformation diagram) from the material composition. The initial grain size influences the transformation kinetics. Another main phenomenon is the efficiency of the cooling bath. The results of the simulation (phase distribution, distortion, residual stresses) strongly depend on these input conditions. Thus, the effect of input data variations on final results must be studied. The modeling approach is validated by comparisons with micrographic observations. Another solution to determine the reliability of the models is to observe the local properties in the quenched part. The prediction of the local micro hardness can be used to evaluate the accuracy of the quenching models.

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