The result of the carburizing has been used as an input for the quenching simulation with heat transfer coefficients (HTC) corresponding to the typical oil quenching used for this type of bevel gear. As shown in Figure 4, for a 10-second cooling, a low-carbon steel (0.2%C) produces ferrite, then pearlite and Bainite, while a high-carbon steel (0.7%C) produces martensite only. Figure 4 shows the quenchability difference between a 0.2% carbon steel and a 0.7% carbon steel content. The increase in carbon content has a positive effect on the quenchability of the part. Typical temperature cycle is shown in Figure 3, as well as carbon distribution at the end of the process. The input data used for the simulation setup are the furnace temperature and carbon content. In Equation 1, C is the carbon content and D is the diffusivity, which varies as a function of the temperature. The FORGE software’s unique capability to deal with large mesh with short computational time is key for this type of simulation.Īt each time step, the carbon content is updated based upon the solution of a diffusion-type equation. The challenge for the simulation, apart from having the proper models to describe the diffusion of the carbon element into the part, is the software’s ability to refine the mesh in the areas where the diffusion occurs.
#Jmatpro vs thermocalc software#
An elasto-visco-plastic material model was used, and flow curves come from JMatPro ® simulation software (Sente Software). Simulations have been performed with Transvalor’s FORGE ® simulation package. In the presented example, the forging is a two-stage warm forging followed by the piercing of the central hole (see Figure 2). Net shape or near net shape is the forging of choice for such a part, which implies the use of a cold or warm forging process. After several hours, the carbon content increases on the surface area of the part, providing the expected properties. A low-carbon steel is maintained in a container filled with high-temperature carbon monoxide. This can be achieved through the carburizing process (see Figure 1B ). A possible solution to this dilemma is to use different carbon content on a different area of the part. On the other hand, low carbon could manage fatigue but marks would soon show on the surface. Figure 1a Figure 1bĪlthough high-carbon steel would bring the requested surface toughness, fatigue properties would likely not be acceptable. To avoid both damage of the surface and fatigue cracks, hardness on the surface and ductility in the core of the material are required. This component will have to sustain continuous loading and unloading cycles generated by the contact with another moving metallic (hard) part (see Figure 1A). The bevel gear is a typical mechanical part produced in large quantities. This article presents two examples to illustrate the carburizing and nitriding heat treatment processes. The simulation of this process is helpful for the engineer to optimize the process. The nitriding process uses the same concept but with nitrogen instead of carbon. While the carbon content (%C) is fairly known at the locations where the carbon has diffused, it is harder to anticipate how far the carbon has diffused. By adjusting the parameters such as temperature and time, the carbon will diffuse into the part to a certain thickness. Carburizing is a process where the part is placed in a confined environment regulated by its carbon content. (Photo courtesy of Advanced Heat Treat Corp.)Ĭarburizing and nitriding treatments have the same goal: increase hardness on the surface while keeping the core ductility.
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